Tsunami Glossary - Version 12

Intergovernmental OceanographicCommission of UNESCO

International Tsunami Information Centre

UNESCO 2006

GLOSSARY

IOC/INF-1221Hawaii, January 2006

Original: English

The designations employed and the presentation of the material in this publication do not implythe expression of any opinion whatsoever on the part of the Secretariat of UNESCO concerningthe legal status of any country or territory, or its authorities, or concerning the delimitation of thefrontiers of any country or territory.

UNESCO-IOC. IOC Information document No. 1221

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For bibliographic purpose, this document should be cited as follows:

Tsunami Glossary. . Paris, UNESCO, 2006.

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TSUNAMI CLASSIFICATION11CHARACTERISTICS OF THE

TSUNAMI PHENOMENA

1

A tsunami travels outward from the source region

as a series of waves. Its speed depends upon the

depth of the water, and consequently the waves

undergo accelerations or decelerations in

passing respectively over an ocean bottom of

increasing or decreasing depth. By this process

the direction of wave propagation also changes,

and the wave energy can become focused or

defocused. In the deep ocean, tsunami waves

can travel at speeds of 500 to 1,000 kilometers

(km) per hour. Near the shore, however, a

tsunami slows down to just a few tens of

kilometers per hour. The height of a tsunami also

depends upon the water depth. A tsunami that is

just a meter in height in the deep ocean can grow

to tens of meters at the shoreline. Unlike familiar

wind-driven ocean waves that are only a

disturbance of the sea surface, the tsunami wave

energy extends to the ocean bottom. Near the

shore, this energy is concentrated in the vertical

direction by the reduction in water depth, and in

the horizontal direction by a shortening of the

wavelength due to the wave slowing down.

Tsunamis have periods (the time for a single

wave cycle) that may range from just a few

minutes to as much as an hour or exceptionally

more. At the shore, a tsunami can have a wide

variety of expressions depending on the size and

period of the waves, the near-shore bathymetry

and shape of the coastline, the state of the tide,

and other factors. In some cases a tsunami may

only induce a relatively benign flooding of low-

lying coastal areas, coming onshore similar to a

rapidly rising tide. In other cases it can come

onshore as a bore - a vertical wall of turbulent

water full of debris that can be very destructive. In

most cases there is also a drawdown of sea level

preceding crests of the tsunami waves that

results in a receding of the waterline, sometimes

by a kilometer or more. Strong and unusual

ocean currents may also accompany even small

tsunamis.

Damage and destruction from tsunamis is the

direct result of three factors: inundation, wave

impact on structures, and erosion. Deaths occur

by drowning and physical impact or other trauma

when people are caught in the turbulent, debris-

laden tsunami waves. Strong tsunami-induced

Photo courtesy of Bishop MuseumArchives.

MAREMOTO

Spanish term for tsunami.

currents have led to the erosion of foundations

and the collapse of bridges and seawalls.

Floatation and drag forces have moved houses

and overturned railroad cars. Tsunami associated

wave forces have demolished frame buildings

and other structures. Considerable damage also

is caused by floating debris, including boats, cars,

and trees that become dangerous projectiles that

may crash into buildings, piers, and other

vehicles. Ships and port facilities have been

damaged by surge action caused by even weak

tsunamis. Fires resulting from oil spills or

combustion from damaged ships in port, or from

ruptured coastal oil storage and refinery facilities,

can cause damage greater than that inflicted

directly by the tsunami. Other secondary damage

can result from sewage and chemical pollution

following the destruction. Damage of intake,

discharge, and storage facilities also can present

dangerous problems. Of increasing concern is

the potential effect of tsunami drawdown, when

receding waters uncover cooling water intakes

associated with nuclear plants.

Synonym for atmospheric tsunami.

Tsunami-like waves generated by a rapidlymoving atmospheric pressure front moving over ashallow sea at about the same speed as thewaves, allowing them to couple.

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IR-COUPLED TSUNAMI

TMOSPHERIC TSUNAMI

ISTORICAL TSUNAMI

OCAL TSUNAMI

A tsunami documented to occur througheyewitness or instrumental observation within thehistorical record.

A tsunami from a nearby source for which itsdestructive effects are confined to coasts within100 km of the source. A local tsunami is usuallygenerated by an earthquake, but can also becaused by a landslide or a pyroclastic flow from avolcanic eruption.

Damage caused by the 22 May 1960 Chilean tsunami.

Photo courtesy of Ilustre Municipalidad de Maullin, USGS

Circular 1187.

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ICROTSUNAMI

CEAN-WIDE TSUNAMI

A tsunami of such small amplitude that it mustbe observed instrumentally and is not easilydetected visually.

A tsunami capable of widespread destruction, notonly in the immediate region of its generation butacross an entire ocean. All ocean-wide tsunamishave been generated by major earthquakes.Synonym for teletsunami or distant tsunami.

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PALEOTSUNAMI

Tsunami occurring prior to the historical record orfor which there are no written observations.

Numerical modelling snapshots of the water surface 10

minutes after a pyroclastic flow on the southeastern part of

Monserrat Island led to a submarine landslide and the

generation of a tsunami.

Paleotsunami research is based primarily on theidentification, mapping, and dating of tsunamideposits found in coastal areas, and theircorrelation with similar sediments foundelsewhere locally, regionally, or across oceanbasins. In one instance, the research has led to anew concern for the possible future occurrence ofgreat earthquakes and tsunamis along thenorthwest coast of North America. In anotherinstance, the record of tsunamis in the Kuril-Kamchatka region is being extended muchfurther back in time.As work in this field continuesit may provide a significant amount of newinformation about past tsunamis to aid in theassessment of the tsunami hazard.

A tsunami capable of destruction in a particulargeographic region, generally within about 1,000km of its source. Regional tsunamis alsooccasionally have very limited and localizedeffects outside the region.

Most destructive tsunami can be classified aslocal or regional, meaning their destructiveeffects are confined to coasts within 100 km, or upto 1,000 km, respectively, of the source -- usuallyan earthquake. It follows many tsunami relatedcasualties and considerable property damagealso comes from these tsunamis. Between 1975and 2005 there were 22 local or regionaltsunamis in the Pacific and adjacent seas thatresulted in deaths and property damage.

For example, a regional tsunami in 1983 in theSea of Japan or East Sea, severely damagedcoastal areas of Japan, Korea, and Russia,causing more than $800 million in damage, andmore than 100 deaths. Then, after nine yearswithout an event, 11 locally destructive tsunamisoccurred in just a seven-year period from 1992 to1998, resulting in over 4,200 deaths andhundreds of millions of dollars in propertydamage. In most of these cases, tsunamimitigation efforts in place at the time were unableto prevent significant damage and loss of life.However, losses from future local or regionaltsunamis can be reduced if a denser network ofwarning centers, seismic and water-level

REGIONAL TSUNAMI

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warning centres, seismic and water-levelreporting stations, and better communicationsare established to provide a timely warning, and ifbetter programmes of tsunami preparedness andeducation can be put in place.

Earthquakes generating tsunamis in the Caribbean and

adjacent seas. Source: ITDB, 2005.

Earthquakes generating tsunamis in the Mediterranean

and connected seas. Source: ITDB, 2005.

Earthquakes generating tsunamis in the Southwest Pacific.

Source: ITDB, 2005. Red circles show tsunamis causing

greatest damage according to the Imamura-Soloviev

tsunami intensity scale. Grey circles are non-tsunamigenic

earthquakes. The size of the circle is scaled to the

magnitude of the earthquake.

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More than 80% of the world's tsunamis are observed in thePacific where large earthquakes occur as tectonic platesare subducted along the Pacific Ring of Fire. Top:Epicentre of all tsunamigenic earthquakes. Middle:Epicentre of tsunamis causing damage or casualties. TheSouthwest Pacific is a source area of local and sub-regional destructive tsunamis. Bottom: Epicentre oftsunamis causing damage or casualties more than 1,000km away. These are the tsunami hazard zones fordestructive Pacific-wide tsunamis based on historicalrecords. Source: Pacific Tsunami Warning Center.

TELETSUNAMI OR DISTANT TSUNAMI

A tsunami originating from a far away source,generally more than 1,000 km away.

ess frequent, but more hazardousare or tsunamis.

Usually starting as a local tsunami that causesextensive destruction near the source, thesewaves continue to travel across entire oceanbasin with sufficient energy to cause additionalcasualties and destruction on shores more than

from the source. In the last

L than regionaltsunamis, ocean-wide distant

an

1,000 kilometres 200

years, there have been at least destructive-wide tsunamis.

The most destructive Pacific-wide tsunami ofrecent history was generated by a massiveearthquake off the coast of Chile on 22 May1960. All Chilean coastal towns between the36th and 44th parallels were either destroyed orheavily damaged by the action of the tsunamiand the quake. The combined tsunami andearthquake toll included 2,000 killed, 3,000injured, two million homeless, and $550 milliondamage. Off the coast of Corral, Chile, the waveswere estimated to be 20 metres (67 feet) high.The tsunami caused 61 deaths in Hawaii, 20 inthe Philippines, and 138 in Japan. Estimateddamages were US $50 million in Japan, US $24million in Hawaii and several millions of dollarsalong the west coast of the United States andCanada. Distant wave heights varied from slightoscillations in some areas to 12 metres(40 feet) at Pitcairn Island, 11 metres at Hilo,Hawaii, and six metres at some places in Japan.

21ocean

immediate response by the world's leaders andled to the development of the Indian Oceantsunami warning and mitigation system in 2005.The event also raised awareness of tsunamihazards globally, and new systems wereestablished in the Caribbean, the Mediterraneanand Atlantic.

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The tsunami of 26 December 2004 destroyed the nearby

city of Banda Aceh leaving only a few structures standing.

Photo courtesy of Yuichi Nishimura, Hokkaido University.

The worst tsunami catastrophe in historyoccurred in the Indian Ocean on 26 December2004, when a M9.3 earthquake off of thenorthwest coast of Sumatra, Indonesiaproduced a ocean-wide tsunami that hit Thailandand Malaysia to the east, and Sri Lanka, India,the Maldives, and Africa to the west as ittraversed across the Indian Ocean. Nearly250,000 people lost their lives and more than amillion people were displaced, losing theirhomes, property, and their livelihoods. Themagnitude of death and destructiveness caused

Sediment layers deposited from successive waves of 26

December 2004 Indian Ocean tsunami, as observed in

Banda Aceh, Indonesia. Photo courtesy of Yuichi

Nishimura, Hokkaido University.

TSUNAMI

Japanese term meaning wave (“nami”) in aharbour (“tsu”). A series of traveling waves ofextremely long length and period, usuallygenerated by disturbances associated withearthquakes occurring below or near the oceanfloor. (Also called seismic sea wave and,incorrectly, tidal wave). Volcanic eruptions,submarine landslides, and coastal rockfalls canalso generate tsunamis, as can a large meteoriteimpacting the ocean. These waves may reachenormous dimensions and travel across entireocean basins with little loss of energy. Theyproceed as ordinary gravity waves with a typicalperiod between 10 and 60 minutes. Tsunamissteepen and increase in height on approachingshallow water, inundating low-lying areas, andwhere local submarine topography causes thewaves to steepen, they may break and causegreat damage. Tsunamis have no connectionwith tides; the popular name, tidal wave, isentirely misleading.

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SUNAMI EARTHQUAKE

SUNAMI SEDIMENTS

An earthquake that produces an unusually largetsunami relative to the earthquake magnitude(Kanamori,1972). Tsunami earthquakes arecharacterized by a very shallow focus, faultdislocations greater than several metres, andfault surfaces smaller than those for normalearthquakes. They are also slow earthquakes,with slippage along their faults occurring moreslowly than would occur in normal earthquakes.The last events of this type were in 1992(Nicaragua) and 1996 (Chimbote, Peru).

Sediments deposited by a tsunami. The findingof tsunami sediment deposits within thestratigraphic soil layers provides information onthe occurrence of historical and paleotsunamis.The discovery of similarly-dated deposits atdifferent locations, sometimes across oceanbasins and far from the tsunami source, can beused to map and infer the distribution of tsunamiinundation and impact.

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Tsunami generated by 26 May 1983, Japan Sea

earthquake approaching Okushiri Island, Japan. Photo

courtesy of Tokai University.

Destruction along the waterfront of Hilo, Hawaii from thePacific-wide tsunami generated off the coast of UnimakIsland,Aleutian Island, USAon 1April 1946.

GENERAL TSUNAMITERMSGENERAL TSUNAMITERMS

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This section contains general terms used in

tsunami mitigation and in tsunami generation and

modelling.

B

B

REAKER

REAKWATER

A sea-surface wave that has become so steep(wave steepness of 1/7) that the crest outracesthe body of the wave and it collapses into aturbulent mass on shore or over a reef. Breakingusually occurs when the water depth is less than1.28 times the wave height. Roughly, three kindsof breakers can be distinguished, dependingprimarily on the gradient of the bottom: a) spillingbreakers (over nearly flat bottoms) which form afoamy patch at the crest and break gradually overa considerable distance; b) plunging breakers(over fairly steep bottom gradients) which peakup, curl over with a tremendous overhangingmass and then break with a crash; c) surgingbreakers (over very steep bottom gradients)which do not spill or plunge but surge up thebeach face. Waves also break in deep water ifthey build too high while being generated by thewind, but these are usually short-crested and aretermed whitecaps.

An offshore or onshore structure, such as a wall,water gate, or other in-water wave-dissipatingobject that is used to protect a harbour or beachfrom the force of waves.

Sea wall with stairway evacuation route used to protect acoastal town against tsunami inundation in Japan. Photocourtesy of River Bureau, Ministry of Land, Infrastructureand Transport, Japan.

EDDY

By analogy with a molecule, a “glob” of fluid withinthe fluid mass that has a certain integrity and lifehistory of its own; the activities of the bulk fluidbeing the net result of the motion of the eddies.

Eddies generated by the interactions of tsunami waves asthey hit the coast of Sri Lanka, 26 December 2004. Photocourtesy of Digital Globe.

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Water gate used to protect against tsunami waves on

Okushiri Island, Japan. The gate begins to automatically

close within seconds after earthquake shaking triggers its

seismic sensors. Photo courtesy of ITIC.

E

E

STIMATED TIME OF ARRIVAL (ETA)

VACUATION MAP

Time of tsunami arrival at some fixed location, asestimated from modelling the speed and refractionof the tsunami waves as they travel from thesource. ETA is estimated with very good precisionif the bathymetry and source are well known (lessthan a couple of minutes).

A drawing or representation that outlines dangerzones and designates limits beyond whichpeople must be evacuated to avoid harm fromtsunami waves. Evacuation routes aresometimes designated to ensure the efficientmovement of people out of the evacuation zoneto evacuation shelters.

Elevated platform used for tsunami evacuation that alsoserves as a high-elevation scenic vista point for tourist.Okushiri Island, Japan. Photo courtesy of ITIC.

Emergency shelter building that also acts as communitycent e and Museum for Disaster Prevention. Kisei, MiePrefecture, Japan. The building is 22-m high, has five floorscovering 320 m , and holds 500 persons. Info courtesy ofhttp://www.webmie.or.jp.

r

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ISTORICAL TSUNAMI DATA

RAVEL TIME

RAVEL TIME MAP

EICHE

EISMIC SEA WAVE

Historical data are available in many forms and atmany locations. These forms include publishedand unpubl ished catalogs of tsunamioccurrences, personal narratives, marigraphs,tsunami amplitude, runup and inundation zonemeasurements, field investigation reports,newspaper accounts, film, or video records.

A seiche may be initiated by a standing waveoscillating in a partially or fully enclosed body ofwater. It may be initiated by long period seismicwaves (an earthquake), wind and water waves, ora tsunami.

Tsunamis are sometimes referred to as seismicsea waves because they are most oftengenerated by earthquakes.

Time required for the first tsunami wave topropagate from its source to a given point on acoastline.

Map showing isochrons or lines of equal tsunamitravel time calculated from the source outwardstoward terminal points on distant coastlines.

8

Inundation and Evacuation Map created for the coastal

town of Pucusana, Peru.

TSUNAMI DAMAGE

Loss or harm caused by a destructive tsunami.More specifically, the damage caused directlyby tsunamis can be summarized into thefollowing: 1) deaths and injuries; 2) housesdestroyed, partially destroyed, inundated,flooded, or burned; 3) other property damage andloss; 4) boats washed away, damaged ordestroyed; 5) lumber washed away; 6) marineinstallations destroyed, and; 7) damage to public

utilities such as railroads, roads, electric powerplants, water supply installations, etc. Indirectsecondary tsunami damage can be: 1) Damageby fire of houses, boats, oil tanks, gas stations,and other facilities; 2) environmental pollutioncaused by drifting materials, oil, or othersubstances; 3) outbreak of disease of epidemicproportions, which could be serious in denselypopulated areas.

TSUNAMI BORE

A steep, turbulent, rapidly moving tsunami wavefront, typically occurring in a river mouth orestuary.

Banda Aceh, Sumatra, Indonesia. The tsunami of 26

December 2004 completely razed coastal towns and

villages, leaving behind only sand, mud, and water where

once there had been thriving communities of homes,

offices, and green space. Photo courtesy of DigitalGlobe.

9

Tsunami bore entering Wailua River, Hawaii during the

1946 Aleutian Island tsunami. Photo courtesy of Pacific

Tsunami Museum.

Massive destruction in the town of Aonae on Okushiri

Island, Japan caused by the regional tsunami of 12 July

1993. Photo courtesy of Dr. Eddie Bernard, NOAAPMEL

Travel times (in hours) for the 22 May 1960 Chile tsunamicrossing the Pacific basin. This tsunami was extremelydestructive along the nearby coast of Chile, and thetsunami also caused significant destruction and casualtiesas far away as Hawaii and Japan. The awareness andconcern raised by this Pacific-wide tsunami ultimately led tothe formation of the PTWS.

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SUNAMI DISPERSION

SUNAMI EDGE WAVE

SUNAMI FORERUNNER

SUNAMI GENERATION

Redistribution of tsunami energy, particularly as afunction of its period, as it travels across a body ofwater.

Wave generated by a tsunami that travels alongthe coast.

A series of oscillations of the water levelpreceding the arrival of the main tsunami waves,mainly due to the resonance in bays and shelvesthat could occur before the arrival of the maintsunami.

Tsunamis are most frequently caused byearthquakes, but can also result from landslides,volcanic eruptions, and very infrequently bymeteorites or other impacts upon the oceansurface. Tsunamis are generated primarily bytectonic dislocations under the sea whichare caused by shallow focus earthquakes alongareas of subduction. The upthrusted anddownthrusted crustal blocks impart potentialenergy into the overlying water mass with drasticchanges in the sea level over the affected region.The energy imparted into the water mass resultsin tsunami generation, i.e. energy radiating awayfrom the source region in the form of long periodwaves.

Tsunamis can be generated by submarine landslides, or bysubaerial landslides that enter the water. Courtesy of LDG-France.

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Tsunamis are most often generated by shallowearthquakes.

SEA SURFACE

SEA SURFACE

SEA SURFACE

SEA SURFACE

SEA FLOOR

SEA FLOOR

SEA FLOOR

SEA FLOOR

FAULT

FOCUS

Most tsunamis are generated by large, shallow, thrust

earthquakes that occur as a tectonic plate is subducted.

Shallow earthquakes also occur along spreading ridges,

but these are not large enough to cause tsunamis. Large,

shallow earthquakes also occur along transform faults, but

there is only minor vertical motion during the faulting so no

tsunamis are generated.

MOST TSUNAMI

GENERATED HERESPREADINGRIDGE

SUBDUCTION

LITHOSPERE

TRANSFORMFAULT

LAND

MAGMAS

ASTHENOSPHERE

SHALLOWINTERMEDIATEDEEP

MAGMA

TRENCH

OCEAN

EARTHQUAKES

TSUNAMI GENERATION THEORY

The theoretical problem of generation of thegravity wave (tsunami) in the layer of elastic liquid(an ocean) occurring on the surface of elasticsolid half-space (the crust) in the gravity field canbe studied with methods developed in thedynamic theory of elasticity. The sourcerepresenting an earthquake focus is adiscontinuity in the tangent component of thedisplacement on some element of area within thecrust. For conditions representative of the Earth'soceans, the solution of the problem differs verylittle from the joint solution of two more simpleproblems: the problem of generation of thedisplacement field by the given source in the solidelastic half-space with the free boundary (thebottom) considered quasi-static and the problemof the propagation of gravity wave in the layer ofheavy incompressible liquid generated by theknown (from the solution of the previous problem)motion of the solid bottom. There is thetheoretical dependence of the gravity waveparameters on the source parameters (depth andorientation). One can roughly estimate thequantity of energy transferred to the gravity waveby the source. In general, it corresponds to theestimates obtained with empirical data. Also,tsunamis can be generated by other differentmechanisms such as volcanic or nuclearexplosions, landslides, rock falls, and submarineslumps.

TSUNAMI HAZARD

The probability that a tsunami of a particular sizewill strike a particular section of coast.

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SUNAMI HAZARD ASSESSMENT

SUNAMI IMPACT

Documentation of tsunami hazards for a coastalcommunity is needed to identify populations andassets at risk, and the level of that risk. Thisassessment requires knowledge of probabletsunami sources (such as earthquakes,landslides, and volcanic eruptions), theirlikelihood of occurrence, and the characteristicsof tsunamis from those sources at differentplaces along the coast. For those communities,data of earlier (historical and paleotsunamis)tsunamis may help quantify these factors. Formost communities, however, only very limited orno past data exist. For these coasts, numericalmodels of tsunami inundation can provideestimates of areas that will be flooded in the eventof a local or distant tsunamigenic earthquake or alocal landslide.

Although infrequent, tsunamis are among themost terrifying and complex physical phenomenaand have been responsible for great loss of lifeand extensive destruction to property. Becauseof their destructiveness, tsunamis have importantimpacts on the human, social, and economicsectors of societies. Historical records show thatenormous destruction of coastal communitiesthroughout the world has taken place and that thesocio-economic impact of tsunamis in the pasthas been enormous. In the Pacific Ocean where

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Tsunamis can be generated by pyroclastic flowsassociated with volcanic eruptions. Courtesy of LDG-France.

Global tsunami source zones. Tsunami hazards exist in alloceans and basins, but occur most frequently in the PacificOcean. Tsunamis can occur anywhere and at any timebecause earthquakes cannot be accurately predicted.

tsunami evacuation maps and procedures. Atpresent, such modelling has only been carriedout for a small fraction of the coastal areas at risk.Sufficiently accurate modelling techniques haveonly been available in recent years, and thesemodels require training to understand and usecorrectly, as well as input of detailed bathymetricand topographic data in the area being modeled.

Numerical models have been used in recentyears to simulate tsunami propagation andinteraction with land masses. Such modelsusually solve similar equations but often employdifferent numerical techniques and are applied todifferent segments of the total problem of tsunamipropagation from generation regions to distantareas of runup. For example, several numericalmodels have been used to simulate theinteraction of tsunamis with islands. Thesemodels have used finite difference, finiteelement, and boundary integral methods to solvethe linear long wave equations. These modelssolve these relatively simple equations andprovide reasonable simulations of tsunamis forengineering purposes.

Historical data are often very limited for mostcoastlines. Consequently, numerical modellingmay be the only way to estimate potential risk.Techniques now exist to carry out thisassessment. Computer software and the trainingnecessary to conduct this modelling are availablethrough programmes such as the IOC TsunamiInundation Modelling Exchange (TIME)Programme.

the majority of these waves have beengenerated, the historic record shows tremendousdestruction with extensive loss of life andproperty.

In Japan, which has one of the most populatedcoastal regions in the world and a long history ofearthquake activity, tsunamis have destroyedentire coastal populations. There is also a historyof severe tsunami destruction in Alaska, theHawaiian Islands, and South America, althoughrecords for these areas are not as extensive. Thelast major Pacific-wide tsunami occurred in 1960.Many other local and regional destructivetsunamis have occurred with more localizedeffects.

Estimated tsunami inundation at Iquique, Chile, based on

numerical model results.

TSUNAMI NUMERICAL MODELLING

Mathematical descriptions that seek to describethe observed tsunami and its effects.

Often the only way to determine the potentialrunups and inundation from a local or distanttsunami is to use numerical modelling, since datafrom past tsunamis is usually insufficient. Modelscan be initialized with potential worst casescenarios for the tsunami sources or for thewaves just offshore to determine correspondingworst case scenarios for runup and inundation.Models can also be initialized with smallersources to understand the severity of the hazardfor the less extreme but more frequent events.This information is then the basis for creating

Calculated maximum tsunami wave heights for a M9.0

Cascadia subduction zone earthquake. The model was

calculated after tsunami deposits found in Japan and

elsewhere suggested that a repeat of the 1700 Cascadia

great earthquake would generate a destructive

teletsunami. Courtesy of Kenji Satake, Geological Survey

of Japan.

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TSUNAMI OBSERVATION

Notice, observation or measurement of sea levelfluctuation at a particular point in time caused bythe incidence of a tsunami on a specific point.

Complex numerical model calculated to match the 1958

Lituya Bay, Alaska landslide-generated local tsunami

which caused the largest runup ever recorded (525 m).

The complex model matches very closely the detail of the

second order eddies and splash effects that laboratory

experiments showed. Courtesy of Galen Gisler, Los

Alamos National Laboratory.

TSUNAMI PREPAREDNESS

Readiness of plans, methods, procedures andactions taken by government officials and thegeneral public for the purpose of minimizingpotential risk and mitigating the effects of futuretsunamis. The appropriate preparedness for awarning of impending danger from a tsunamirequires knowledge of areas that could beflooded (tsunami inundation maps) andknowledge of the warning system to know whento evacuate and when it is safe to return.

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1946 Aleutian Islands tsunami rushing ashore in Hilo,

Hawaii. Photo courtesy of Pacific Tsunami Museum.

International tsunami hazard sign.

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SUNAMI RESONANCE

SUNAMI RISK

SUNAMI SIMULATION

The continued reflection and interference oftsunami waves from the edge of a harbour ornarrow bay which can cause amplification of thewave heights, and extend the duration of waveactivity from a tsunami.

The probability of a particular coastline beingstruck by a tsunami multiplied by the likelydestructive effects of the tsunami and by thenumber of potential victims. In general terms,risk is the hazard multiplied by the exposure.

Numerical model of tsunami generation,propagation, and inundation.

TSUNAMI PROPAGATION

Tsunamis travel outward in all directions from thegenerating area, with the direction of the mainenergy propagation generally being orthogonalto the direction of the earthquake fracture zone.Their speed depends on the depth of water, sothat the waves undergo accelerations anddecelerations in passing over an ocean bottom ofvarying depth. In the deep and open ocean, theytravel at speeds of 500 to 1,000 km per hour (300to 600 miles per hour). The distance betweensuccessive crests can be as much as 500 to 650km (300 to 400 miles). However, in the openocean, the height of the waves is generally lessthan a metre (three feet) even for the mostdestructive teletsunamis, and the waves passunnoticed. Variations in tsunami propagationresult when the propagation impulse is strongerin one direction than in others because of theorientation or dimensions of the generating areaand where regional bathymetric and topographicfeatures modify both the waveform and rate ofadvance. Specifically, tsunami waves undergo a

Model of tsunami propagation in the southeast Pacific, nine

hours after generation. Source: Antofagasta, Chile (30 July

1995). Courtesy of LDG-France.

Marquesas Is.

Tahiti

Galapagos Is.

Easter Is.

Epicentre

Juan Fernández Is.

process of wave refraction and reflectionthroughout their travel. Tsunamis are unique inthat the energy extends through the entire watercolumn from sea surface to the ocean bottom. Itis this characteristic that accounts for the greatamount of energy propagated by a tsunami.

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Evacuation Route sign used in Chile. Photo courtesy of

ITIC.

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TS

SUNAMI SOURCE

SUNAMI VELOCITY OR

HALLOW WATER VELOCITY

Point or area of tsunami origin, usually the site ofan earthquake, volcanic eruption, or landslidethat caused large-scale rapid displacement of thewater to initiate the tsunami waves.

The velocity of an ocean wave whose length issufficiently large compared to the water depth(i.e., 25 or more times the depth) can beapproximated by the following expression:

:

c: is the wave velocity

g: the acceleration of gravity

h: the water depth.

Thus, the velocity of shallow-water waves isindependent of wave length L. In water depthsbetween ½ L and 1/25 L it is necessary to use amore precise expression:

�

� � �

Where

c = (gh)

c = ( (gL/2 )[tanh(2 h/L)])

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SUNAMI ZONATION

(TSUNAMI ZONING)

SUNAMIC

SUNAMIGENIC

Designation of distinctive zones along coastalareas with varying degrees of tsunami risk andvulnerability for the purpose of disasterpreparedness, planning, construction codes, orpublic evacuation.

Having features analogous to those of a tsunamior descriptive of a tsunami.

Having generated a tsunami: a tsunamigenicearthquake, a tsunamigenic landslide.

15

Destruction of Hilo Harbor, Hawaii, 1 April 1946. The

tsunami generated off the coast of Unimak Island, Aleutian

Islands raced across the Pacific, coming ashore in Hawaii

less than five hours later. Photo courtesy of NOAA.

Wave height and water depth. In the open ocean, a

tsunami is often only a tens of centimeters high, but its wave

height grows rapidly in shallow water. Tsunami wave

energy extends from the surface to the bottom in the

deepest waters. As the tsunami attacks the coastline, the

wave energy is compressed into a much shorter distance

creating destructive, life threatening waves.

This section contains terms used to measure and

describe tsunami waves on mareographs and in

the field during a survey, and terms used to

describe the size of the tsunami.

A

D

E

I

I

RRIVAL TIME

ROP

LAPSED TIME

NITIAL RISE

NTENSITY

Time of the first maximum of the tsunami waves.

The length of a wave along its crest. Sometimescalled crest width.

The downward change or depression in sea levelassociated with a tsunami, a tide, or some longterm climatic effect.

Time between the maximum level arrival timeand the arrival time of the first wave.

Time of the first minimum of the tsunami waves.

Extreme strength, force, or energy.

CREST LENGTH

SURVEYS ANDMEASUREMENTSSURVEYS ANDMEASUREMENTS

33

16

INUNDATION

The horizontal distance inland that a tsunamipenetrates, generally measured perpendicularlyto the shoreline.

I

I

NUNDATION (MAXIMUM )

NUNDATION AREA

Maximum horizontal penetration of the tsunamifrom the shoreline. A maximum inundation ismeasured for each different coast or harbouraffected by the tsunami.

Area flooded with water by the tsunami.

Tsunami inundation generated by the earthquake of

May 1983, at Oga aquarium in Japan26 . Photo courtesy

of Takaaki Uda, Public Works Research Institute, Japan.

INUNDATION LINE

L

M

M

EADING WAVE

AGNITUDE

EAN HEIGHT

Inland limit of wetting, measured horizontallyfrom the mean sea level (MSL) line. The linebetween living and dead vegetation is sometimesused as a reference. In tsunami science, thelandward limit of tsunami runup.

First arriving wave of a tsunami. In some cases,the leading wave produces an initial depressionor drop in sea level, and in other cases, anelevation or rise in sea level. When a drop in sealevel occurs, sea level recession is observed.

A number assigned to a quantity by means ofwhich the quantity may be compared with otherquantities of the same class.

Average height of a tsunami measured from thetrough to the crest after removing the tidalvariation.

Aflowing over; inundation.

OVERFLOW

POST-TSUNAMI SURVEY

Tsunamis are relatively rare events and most oftheir evidence is perishable. Therefore, it is veryimportant that reconnaissance surveys beorganized and carried out quickly and thoroughly

after each tsunami occurs, to collect detailed datavaluable for hazard assessment, modelvalidation, and other aspects of tsunamimitigation.

17

After a major tsunami, physical oceanographers, socialscientists, and engineers conduct post-tsunami surveys tocollect information. These data, including runup andinundation, deformation, scour, building and structuralimpact, wave arrival descriptions, and social impact, areimportant for designing better mitigation to reduce theimpacts of tsunami on life and property. Photo courtesy ofPhilip Liu, Cornell University.

Post-tsunami survey measuring runup along a transect

inland from the coast. Courtesy of ICMAM, Chennai, DOD,

India.

In recent years, following each major destructivetsunami, a post-tsunami reconnaissance surveyhas been organized to make measurements ofrunups and inundation limits and to collectassociated data from eyewitnesses such as thenumber of waves, arrival time of waves, andwhich wave was the largest. The surveys havebeen organized primarily on an ad-hoc basis byinternational academic tsunami researchers. A

(http://ioc3.unesco.org/itic/contents.php?id=28)has been prepared by the PTWS to help withprepara t ions of surveys , to ident i fymeasurements and observations to be taken,

P o s t - Ts u n a m i S u r v e y F i e l d G u i d e

Dark area shows inundation area from the 1964 Alaska

tsunami. Photo courtesy of NGDC.

and to standardize data collections. The TsunamiBulletin Board e mail service has also been usedfor quickly organizing international surveys andfor sharing of the observations from impactedareas.

-

RECESSION

Drawdown of sea level prior to tsunami flooding.The shoreline moves seaward, sometimes by akilometre or more, exposing the sea bottom,rocks, and fish. The recession of the sea is anatural warning sign that a tsunami isapproaching.

R

S

M

UNUP DISTRIBUTION

IEBERG TSUNAMI INTENSITY SCALE

ODIFIED SIEBERG SEA-WAVE

INTENSITY SCALE

Set of tsunami runup values measured orobserved along a coastline.

A descriptive tsunami intensity scale, which waslater modified into the Sieberg-Ambraseystsunami intensity scale described below(Ambraseys 1962).

1) Very light. Wave so weak as to be perceptibleonly on tide-gauge records.

2) Light. Wave noticed by those living along theshore and familiar with the sea. On very flatshores generally noticed.

3) Rather strong. Generally noticed. Flooding ofgently sloping coasts. Light sailing vessels or

18

R

R

ISE

UNUP

The upward change or elevation in sea levelassociated with a tsunami, a tropical cyclone,storm surge, the tide, or other long term climaticeffect.

1) Difference between the elevation of maximumtsunami penetration (inundation line) and the sealevel at the time of the tsunami.

2) Elevation reached by seawater measuredrelative to some stated datum such as mean sealevel, mean low water, sea level at the time of thetsunami attack, etc., and measured ideally at apoint that is a local maximum of the horizontalinundation.

3) In practical terms, runup is only measuredwhere there is a clear evidence of the inundationlimit on the shore.

North Shore, Oahu, Hawaii. During the 9 March 1957Aleutian Island tsunami, people foolishly explored theexposed reef, unaware that tsunami waves would return inminutes to inundate the shoreline. Photo by A. Yamauchi,courtesy of Honolulu Star-Bulletin.

Tsunami stripped forested hills of vegetation leaving clear

marker of tsunami runup, Banda Aceh, 26 December 2004

Sumutra tsunami. Photo courtesy of Yuichi Nishimura,

Hokkaido University.

Runup can often be inferred from the vertical extent of dead

vegetation, from debris normally found at ground level that

are observed stuck on electric wires, in trees, or at other

heights, and from water line marks left on building walls. In

extreme cases, cars, boats, and other heavy objects have

been lifted and deposited atop buildings. Banda Aceh,

Indonesia, 26 December 2004. Photo courtesy of C.

Courtney, Tetra Tech EMI.

small boats carried away on shore. Slightdamage to light structures situated near thecoast. In estuaries reversal of the river flow somedistance upstream.

4) Strong. Flooding of the shore to some depth.Light scouring on man-made ground.Embankments and dikes damaged. Lightstructures near the coasts damaged. Solidstructures on the coast injured. Big sailingvessels and small ships carried inland or out tosea. Coasts littered with floating debris.

5) Very strong. General flooding of the shore tosome depth. Breakwater walls and solidstructures near the sea damaged. Lightstructures destroyed. Severe scouring ofcultivated land and littering of the coast withfloating items and sea animals. With theexception of big ships, all other type of vesselscarried inland or out to sea. Big bores in estuaryrivers. Harbour works damaged. Peopledrowned. Wave accompanied by strong roar.

6) Disastrous. Partial or complete destruction ofman-made structures for some distance from theshore. Flooding of coasts to great depths. Bigships severely damaged. Trees uprooted orbroken. Many casualties.

The average height of the one-third highestwaves of a given wave group. Note that thecomposition of the highest waves depends uponthe extent to which the lower waves areconsidered. In wave record analysis, the averageheight of the highest one-third of a selectednumber of waves, this number being determinedby dividing the time of record by the significantperiod.Also called characteristic wave height.

When referring to tsunami waves, it is thespreading of the wave energy over a widergeographical area as the waves propagate awayfrom the source region. The reason for thisgeographical spreading and reduction of waveenergy with distance traveled, is the sphericity ofthe earth. The tsunami energy will beginconverging again at a distance of 90 degreesfrom the source. Tsunami waves propagatingacross a large ocean undergo other changes in

S

S

IGNIFICANT WAVE HEIGHT

PREADING

The 26 December 2004 earthquake resulted in 1.2 m of landsubsidence in the Car Nicobar, Nicobar Islands, India leavinghouses that were once above sea level now permanentlysubmerged. Photo courtesy of ICMAM, Chennai, DOD, India.

configuration primarily due to refraction, butgeographical spreading is also very importantdepending upon the orientation, dimensions, andgeometry of the tsunami source.

The permanent movement of land down(subsidence) or up (uplift) due to geologicprocesses, such as during an earthquake.

SUBSIDENCE (UPLIFT)

19Mareogram (sea level) record of a tsunami.

TSUNAMI AMPLITUDE

Usually measured on a sea level record, it is:1) the absolute value of the difference between aparticular peak or trough of the tsunami and theundisturbed sea level at the time, 2) half thedifference between an adjacent peak and trough,corrected for the change of tide between thatpeak and trough. It is intended to represent thetrue amplitude of the tsunami wave at some pointin the ocean. However, it is often an amplitudemodified in some way by the tide gaugeresponse.

TSUNAMI INTENSITY

TSUNAMI MAGNITUDE

Size of a tsunami based on the macroscopicobservation of a tsunami's effect on humans,objects including various sizes of marine vessels,and buildings.

The original scale for tsunamis was published bySieberg (1923), and later modified byAmbraseys(1962) to create a six-category scale.Papadopoulus and Imamura (2001) proposed anew 12-grade intensity scale which isindependent of the need to measure physicalparameters like wave amplitude, sensitive to thesmall differences in tsunami effects, and detailedenough for each grade to cover the manypossible types of tsunami impact on the humanand natural environment. The scale has 12categories, similar to the Modified MercalliIntensity Scale used for macroseismicdescriptions of earthquake intensity.

Size of a tsunami based on the measurement ofthe tsunami wave on sea level gauges and otherinstruments.

The scale, originally descriptive and more similarto an intensity, quantifies the size by usingmeasurements of wave height or tsunami runup.Iida et al. (1972) described the magnitude (m) asdependent in logarithmic base 2 on the maximumwave height measured in the field, andcorresponding to a magnitude range from -1 to 4:

m = log H

Hatori (1979) subsequently extended this so-called Imamura-Iida scale for far-field tsunamisby including distance in the formulation.Soloviev (1970) suggested that the meantsunami height may be another good indicator oftsunami size, so that the mean tsunami height isequal to 1/square root (H ), and the maximum

intensity would be that measured nearest to thetsunami source. A variation on this is theImamura-Soloviev intensity scale I (Soloviev,1972). Shuto (1993) has suggested themeasurement of H as the height where specifictypes of impact or damage occur, thus proposinga scale which can be used as a predictivequantitative tool for macroscopic effects.

Tsunami magnitudes have also been proposed

2 max

max

that are similar in form to those used to calculateearthquake magnitudes. These include theoriginal formula proposed by Abe (1979) fortsunami magnitude, M

M = logH + B

where H is the maximum single crest or troughamplitude of the tsunami waves (in metres) and Bis a constant, and the far-field applicationproposed by Hatori (1986) which adds a distancefactor into the calculation.

Amount of time that a tsunami wave takes tocomplete a cycle. Tsunami periods typicallyrange from five minutes to two hours.

Difference between the arrival time of the highestpeak and the next one measured on a water levelrecord.

The horizontal distance between similar pointson two successive waves measuredperpendicular to the crest. The wave length andthe tsunami period give information on thetsunami source. For tsunamis generated byearthquakes, the typical wave length rangesfrom 20 to 300 km. For tsunamis generated bylandslides, the wave length is much shorter,ranging from hundreds of metres to tens ofkilometres.

Difference between the elevation of the highestlocal water mark and the elevation of the sealevel at the time of the tsunami. This is differentfrom maximum runup because the water mark isoften not observed at the inundation line, butmaybe halfway up the side of a building or on atree trunk.

1) The highest part of a wave.

2) That part of the wave above still water level.

t:

t

The lowest part of a wave.

T

T

T

W

W

SUNAMI PERIOD

SUNAMI PERIOD (DOMINANT)

SUNAMI WAVE LENGTH

ATER LEVEL (MAXIMUM)

AVE CREST

WAVE TROUGH

20

TIDE, MAREOGRAPH,SEA LEVELTIDE, MAREOGRAPH,SEA LEVEL

44

This section contains terms to describe sea level

and the instruments used to measure tsunamis.

C

D

OTIDAL

EEP-OCEAN ASSESSMENT ANDREPORTING OF TSUNAMIS (DART)

Indicating equality with the tides or a coincidencewith the time of high or low tide.

An instrument for the early detection,measurement, and real-time reporting of tsunamisin the open ocean. Developed by the US NOAAPacific Marine Environmental Laboratory, theDART system consists of a seafloor bottompressure recording system capable of detectingtsunamis as small as one cm, and a mooredsurface buoy for real-time communications. Anacoustic link is used to transmit data from theseafloor to the surface buoy. The data are thenrelayed via a satellite link to ground stations,which demodulate the signals for immediatedissemination to the NOAA tsunami warningscentres. The DART data, along with state-of-the-art numerical modeling technology, are part of atsunami forecasting system package that willprovide site-specific predictions of tsunami impacton the coast.

LOW WATER

The lowest water level reached during a tidecycle. The accepted popular term is low tide.

1) Record made by a mareograph.

2) Any graphic representation of the rise and fallof the sea level, with time as abscissa and heightas ordinate, usually used to measure tides, mayalso show tsunamis.

M MAREOGRAM OR ARIGRAM

17 FEBRUARY 1996 RIAN JAYA TSUNAMII

Mareograms of tsunami signals measured by anunderwater gauge located 50 km outside the entrance toTokyo Bay in about 50 m of water (upper trace), andanother gauge located at the shore (lower trace). Thetsunami is detected on the outside gauge about 40 minutesbefore it reaches shore (arrows). The offshore gauge wasdeveloped by Japan's Port and Harbours ResearchInstitute.

MAREOGRAPH

MEAN SEA LEVEL

A recording sea level gauge. Also known as amarigraph or tide gauge.

The average height of the sea surface, basedupon hourly observation of tide height on theopen coast or in adjacent waters which have free

21

access to the sea. These observations are tohave been made over a “considerable” period oftime. In the United States, mean sea level isdefined as the average height of the surface ofthe sea for all stages of the tide over a 19-yearperiod. Selected values of mean sea level serveas the sea level datum for all elevation surveys inthe United States. Along with mean high water,mean low water, and mean lower low water, meansea level is a type of t idal datum.

A hypothetical water level (exclusive of waverunup from normal wind-generated waves) thatmight result from the most severe combination ofhydrometeorological, geoseismic and othergeophysical factors that is consideredreasonably possible in the region involved, witheach of these factors considered as affecting thelocality in a maximum manner. This levelrepresents the physical response of a body ofwater to maximum applied phenomena such ashurricanes, moving squall lines, other cyclonicmeteorological events, tsunamis, andastronomical tide combined with maximumprobable ambient hydrological conditions suchas wave level with virtually no risk of beingexceeded.

The observed elevation differences betweengeodetic benchmarks are processed throughleast-squares adjustments to determineorthometric heights referred to a common verticalreference surface, which is the reference sealevel. In this way, height values of all benchmarksin the vertical control portion of a surveyingagency are made consistent and can becompared directly to determine differences ofelevation between benchmarks in a geodeticreference system that may not be directlyconnected by lines of geodetic leveling. Thevertical reference surface in use in the UnitedStates, as in most parts of the world,

P

R

ROBABLE MAXIMUM WATER LEVEL

EFERENCE SEA LEVEL

approximates the geoid. The geoid was assumedto be coincident with local mean sea level at 26tidal stations to obtain the Sea Level Datum of1929 (SLD 290). National Geodetic VerticalDatum of 1929 (NGVD 29) became a namechange only; the same vertical reference systemhas been in use in the United States since 1929.This important vertical geodetic control system ismade possible by a universally accepted,reference sea level.

The height of the sea at a given time measuredrelative to some datum, such as mean sea level.

Models using water depths, direction of wave,separation angle, and ray separation betweentwo adjacent rays as input, produce the path ofwave orthogonals, refraction coefficients, waveheights, and travel times.

A system consisting of a device such as a tidegauge for measuring the height of sea level, adata collection platform (DCP) for acquiring,digitizing, and archiving the sea level informationdigitally, and often a transmission system fordelivering the data from the field station to acentral data collection centre. The specificrequirements of data sampling and datatransmission are dependent on the application.The GLOSS programme maintains a corenetwork of sea level stations. For local tsunamimonitoring, one-second sampled data streamsavailable in real time are required. For distanttsunamis, warning centres may be able toprovide adequate warnings using data acquiredin near-real time (one-minute sampled datatransmitted every 15 minutes). Sea level stationsare also used for sea level rise and climatechange studies, where an important requirementis for the very accurate location of the station asacquired through surveying techniques.

R

S

EFRACTION DIAGRAMS

EA LEVEL STATION

SEA LEVEL

22

TIDE GAUGE

TSUNAMETER

A device for measuring the height (rise and fall) ofthe tide. Especially an instrument forautomatically making a continuous graphicrecord of tide height versus time.

An instrument for the early detection,measurement, and real-time reporting oftsunamis in the open ocean. Also known as atsunamimeter. The DART system is atsunameter.

TIDE STATION

A place where tide observations are obtained.

T

T

T

IDAL WAVE

IDE

IDE AMPLITUDE

1) The wave motion of the tides.

2) Often incorrectly used to describe a tsunami,storm surge, or other unusually high andtherefore destructive water levels along a shorethat are unrelated to the tides.

The rhythmic, alternate rise and fall of the surface(or water level) of the ocean, and of bodies ofwater connected with the ocean such as estuariesand gulfs, occurring twice a day over most of theEarth and resulting from the gravitationalattraction of the moon (and, in lesser degrees, ofthe sun) acting unequally on different parts of therotating Earth.

One-half of the difference in height betweenconsecutive high water and low water; hence, halfof the tidal range.

23

Rarotonga sea level station, Avarua Harbor, Cook Islands.

The fiberglass electronics package (a), antenna (b), solar

panel (c) were installed on a pier. Conduit (d) containing

cables connecting the sensor, located at a depth of five feet

below low-tide water level, to the data collection platform

containing the electronics above, was externally attached

to the tube containing the sensor (e).

GLOSS sea level stations employ a number of instruments

to measure sea level, including down-looking radars to

measure sea level. Port Louis, Mauritius. Photo courtesy

of University of Hawaii Sea Level Center.

ACRONYMS &ORGANIZATIONSACRONYMS &ORGANIZATIONS

55

The IOC Global Tsunami Warning and Mitigation

Systems work in partnership with a number of

organizations and utilize specific acronyms to

describe system governance, and the different

tsunami information products.

COMMUNICATIONS PLAN FOR THETSUNAMI WARNING SYSTEM

F

GLOSS

ORECAST POINT

The operations manual for the Tsunami WarningSystem in various regions. The Plan provides ageneral overview of the operational proceduresand of the nature of tsunamis. It lists theseismographic and sea level stationsparticipating in the warning system, the methodsof communication between the stations and theWarning Centre, the criteria for the reporting andissuing of tsunami information messages by theWarning Centre, the recipients of the information,and the methods by which the messages aresent. Official contact information for emergencycommunications is included.

The location where the Tsunami Warning Centremay provide estimates of tsunami arrival time orwave height.

Global Sea-Level Observing System. Acomponent of the Global Ocean ObservingSystem (GOOS). The UNESCO IOC establishedGLOSS in 1985 originally to improve the quality ofsea level data as input to studies of long-term sealevel change. It consists of a core network ofapproximately 300 stations distributed alongcontinental coastlines and throughout each of theworld's island groups. The GLOSS network alsosupports sea level monitoring for tsunamiwarning with minimum operational standards of15-minute data transmissions of one-minutesampled data.

GOOS

GTS

ICG

Global Ocean Observing System. GOOS is apermanent global system for observations,modelling, and analysis of marine and oceanvariables to support operational ocean servicesworldwide. The GOOS Project aims to provideaccurate descriptions of the present state of theoceans, including living resources; continuousforecasts of the future conditions of the sea for asfar ahead as possible; and the basis for forecastsof climate change. The GOOS Project Office,located at the IOC headquarters in Paris since1992, provides assistance in the implementationof GOOS.

Global Telecommunications System of the WorldMeteorological Organization (WMO) that directlyconnects nat ional meteorological andhydrological services worldwide. The GTS iswidely used for the near real-time transmission ofsea level data for tsunami monitoring. The GTSand other robust communications methods areused for the transmission of tsunami warnings.

Intergovernmental Coordination Group. Assubsidiary bodies of the UNESCO IOC, the ICGmeets to promote, organize, and coordinateregional tsunami mitigation activities, includingthe issuance of timely tsunami warnings. TheICG is composed of National Contacts fromMember States in the region. Currently, there areICGs for tsunami warning and mitigation systemsin the Pacific, Indian Ocean, Caribbean andadjacent regions, and the north-eastern Atlantic,the Mediterranean and connected seas.

24

ICG/CARIBE-EWS

ICG/IOTWS

ICG/ITSU

ICG/NEAMTWS

Intergovernmental Coordination Group forTsunami and other Coastal Hazards WarningSystem for the Caribbean and Adjacent Regionsestablished by Resolution XXIII-14 of the 23rdSession of the IOC General Assembly in 2005.The ICG is comprised principally of IOC MemberStates and regional organizations from the WiderCaribbean Region. Through the coordinatingefforts of the IOCARIBE Sub-commission startingin 1993, a Group of Experts formulated a proposalfor the building of the Intra-Americas TsunamiWarning System that was endorsed by the IOCGeneralAssembly in 2002.

Intergovernmental Coordination Group for theIndian Ocean Tsunami Warning and MitigationSystem established by Resolution XXIII-12 of the23rd Session of the IOC General Assembly in2005. The IOC Regional Programme Office inPerth, Australia serves a the IOTWSSecretariat. Presently, there are 27 MemberStates.

International Coordination Group for theInternational Tsunami Warning System in thePacific established by Resolution IV-6 of the 4thSession of the IOC General Assembly in 1965.The ICG/ITSU was renamed to the ICG/PTWS in2005.

Intergovernmental Coordination Group for theTsunami Early Warning and Mitigation System inthe North-easternAtlantic, the Mediterranean andConnected Seas established by Resolution XXIII-13 of the 23rd Session of the IOC GeneralAssembly in 2005. The ICG is comprisedprincipally of IOC Member States bordering thenorth-eastern Atlantic and those bordering orwithin the Mediterranean or connected seas.

(http://ioc3.unesco.org/cartws)

, s

(http://ioc.unesco.org/indotsunami)

(http://www.tsunamiwave.info)

(http://ioc3.unesco.org/neamtws)

ICG/PTWS

I

I

CG TSUNAMI WARNING FOCAL

POINT (TWFP)

CG TSUNAMI NATIONAL CONTACT

(TNC)

IOC

Intergovernmental Coordination Group for thePacific Tsunami Warning and Mitigation System,renamed by Resolution ITSU-XX.1 of the 20thSession of the ICG/ITSU in 2005. Presently,there are 28 Member States. The ICG/PTWSwas formerly the ICG/ITSU. The ITIC in Honoluluserves as the PTWS Secretariat.

7x24 contact person, or other official point ofcontact or address, designated by an ICGMember State government for rapidly receivingand issuing tsunami event information (such aswarnings). The Tsunami Warning Focal Pointhas the responsibility of notifying the emergencyauthority (civil defense or other designatedagency responsible for public safety) of the eventcharacteristics (earthquake and/or tsunami), inaccordance with the procedures of the TsunamiResponse Plan. The Tsunami Warning FocalPoint receives international tsunami warningsfrom the PTWC, NWPTAC, or other regionalwarning centres.

The person designated by an ICG Member Stategovernment to represent his/her country in thecoordination of international tsunami warningand mitigation activities. The person is part of themain stakeholders of the national tsunamiwarning and mitigation system programme. Theperson may be the Tsunami Warning FocalPoint, from the national disaster managementorganization, from a technical or scientificinstitution, or from another agency with tsunamiwarning and mitigation responsibilities.

(http://ioc3.unesco.org/ptws)

Intergovernmental Oceanographic Commissionof UNESCO. The IOC provides Member Statesof the United Nations with an essentialmechanism for global cooperation in the study ofthe ocean. The IOC assists governments to

25

address their individual and collective ocean andcoastal problems through the sharing ofknowledge, information, and technology andthrough the coordination of national program s.

International Tsunami Information Centre. ITICwas established in November 1965 by the IOC ofUNESCO. In 1968, the IOC first convened theICG/ITSU to coordinate tsunami warning andmitigation activities in the Pacific. The ITICserves as the PTWS Secretariat. Additionally,the ITIC provides technical and capacity buildingassistance to Member States for the globalestablishment of tsunami warning and mitigationsystems in the Indian and Atlantic Oceans, theCaribbean and Mediterranean Seas, and otheroceans and marginal seas. In the Pacific, the ITICspecif ically monitors and recommendsimprovements to the PTWS, coordinates tsunamitechnology transfer among Member Statesinterested in establishing regional and nationaltsunami warning systems, acts as aclearinghouse for risk assessment and mitigationactivities, and serves as a resource for thedevelopment, publication, and distribution oftsunami education and preparedness materials.

International Union of Geodesy and Geophysics.The IUGG is a non-governmental, scientificorganization established in 1919, dedicated topromoting and coordinating studies of the Earthand its environment in space. The IUGG TsunamiCommission, established in 1960, is aninternational group of scientists concerned withvarious aspects of tsunamis, including animproved understanding of the dynamics ofgeneration, propagation and coastal runup oftsunami , as well as their consequences tosociety.

,me

,s

Japan Meteorological Agency. JMA established atsunami warning service in 1952. JMA nowserves as a National Tsunami Warning Systemthat continuously monitors 24 hours-a-day all

(http://ioc.unesco.org/iocweb/index.php)

( )

(http://iugg.org)

http://www.tsunamiwave.info

ITIC

IUGG

JMA

seismic activity in Japan, and issues timelyinformation concerning earthquakes andtsunamis. In 2005, the JMA began operations ofthe Northwest Pacific Tsunami Advisory Center( N W P TA C ) . T h e N W P TA C p r o v i d e ssupplementary tsunami information for events inand around Japan and the northwest Pacific inclose coordination with the PTWC.

A warning issued to all participants after there isconfirmation of tsunami waves capable ofcausing destruction beyond the local area.Ocean-Wide Tsunami Warnings containestimated tsunami arrival times (ETAs) at allForecast Points. Ocean-Wide Tsunami WarningBulletins also normally carry information onselected wave heights and other wave reports.The Warning will be cancelled when it isdetermined that the tsunami threat is over. Aslocal conditions can cause wide variations intsunami wave action, the all-clear determinationshould be made by the local action agencies andnot the TWC. In general, after receipt of aTsunami Warning, action agencies can assumeall-clear status when their area is free fromdamaging waves for at least two hours, unlessadditional ETAs have been announced by theTWC (for example for a significant aftershock) orlocal conditions, that may include continuedseiching or particularly strong currents inchannels and harbours, warrant the continuationof the Tsunami Warning status.

(http://www.jma.go.jp/jma)

The principal long-term guide for improving theTWS. The Plan provides a summary of the basicelements which comprise the TWS, a descriptionof its existing components, and an outline of theactivities, data sets, methods, and proceduresthat need to be improved in order to reducetsunami risk. The first edition of the ICG/PTWSMaster Plan was released in 1989. The secondedition was released in 1999.(http://ioc3.unesco.org/itic/categories.php?categ

ory_no=64)

MASTER PLAN

OCEAN-WIDE TSUNAMI WARNING

SAMPLE: Pacific-Wide Tsunami Warning (initial)

TSUNAMI BULLETIN NUMBER 004

26

PACIFIC TSUNAMI WARNING CENTER/NOAA/NWSISSUED AT 2119Z 25 FEB 2005

THIS BULLETIN IS FOR ALL AREAS OF THE PACIFICBASIN EXCEPTALASKA - BRITISH COLUMBIA - WASHINGTON -OREGON - CALIFORNIA.

...APACIFIC-WIDE TSUNAMI WARNING IS IN EFFECT ...

THIS WARNING IS FOR ALL COASTAL AREAS ANDISLANDS IN THE PACIFIC.

AN EARTHQUAKE HAS OCCURRED WITH THESEPRELIMINARY PARAMETERS

ORIGIN TIME - 1804Z 25 FEB 2005COORDINATES - 52.3 NORTH 160.7 EASTLOCATION - OFF EAST COAST OF KAMCHATKAMAGNITUDE - 8.8

MEASUREMENTS OR REPORTS OF TSUNAMI WAVEACTIVITY

GAUGELOCATION LAT LON TIME AMPL PER----------------------------------------------------------------------NIKISKI 60.7N 151.4W 0057Z 0.52M **MINSEVERO KURILSK

50.7N 156.1E 2042Z 0.12M 64MIN

TIME - TIME OF THE MEASUREMENTAMPL - AMPLITUDE IN METERS FROM MIDDLE

TO CREST OR MIDDLE TO TROUGH ORHALF OF THE CREST TO TROUGH

PER - PERIOD OF TIME FROM ONE WAVECREST TO THE NEXT

EVALUATION

SEA LEVEL READINGS CONFIRM THAT A TSUNAMIHAS BEEN GENERATED WHICH COULD CAUSEWIDESPREAD DAMAGE TO COASTS AND ISLANDS INThe PACIFIC. AUTHORITIES SHOULD TAKEAPPROPRIATE ACTION IN RESPONSE TO THISTHREAT. THIS CENTER WILL CONTINUE TO MONITORSEA LEVEL DATA TO DETERMINE THE EXTENT ANDSEVERITY OF THE THREAT.

A TSUNAMI IS A SERIES OF WAVES AND THE FIRSTWAVE MAY NOT BE THE LARGEST. TSUNAMI WAVEHEIGHTS CANNOT BE PREDICTED AND CAN VARYSIGNIFICANTLY ALONG A COAST DUE TO LOCALEFFECTS. THE TIME FROM ONE TSUNAMI WAVE TOTHE NEXT CAN BE FIVE MINUTES TO AN HOUR, ANDTHE THREAT CAN CONTINUE FOR MANY HOURS ASMULTIPLE WAVESARRIVE.

FOR ALL AREAS - WHEN NO MAJOR WAVES AREOBSERVED FOR TWO HOURSAFTER THE ESTIMATEDTIME OF ARRIVAL OR DAMAGING WAVES HAVE NOTOCCURRED FOR AT LEAST TWO HOURS THEN LOCALAUTHORITIES CAN ASSUME THE THREAT IS PASSED.DANGER TO BOATSAND COASTALSTRUCTURES CANCONTINUE FOR SEVERAL HOURS DUE TO RAPIDCURRENTS. AS LOCAL CONDITIONS CAN CAUSE AWIDE VARIATION IN TSUNAMI WAVE ACTION THE ALLCLEAR DETERMINATION MUST BE MADE BY LOCAL

AUTHORITIES.

BULLETINS WILL BE ISSUED HOURLY OR SOONER IFCONDITIONS WARRANT.

PTWC

Established in 1949, the Richard H. HagemeyerPacific Tsunami Warning Center (PTWC) in EwaBeach, Hawaii, acts as the operationalheadquarters for the PTWS and works closelywith other sub-regional and national centres inmonitor ing and evaluat ing potent ia l lytsunamigenic earthquakes. It providesinternational warnings for teletsunamis tocountries in the Pacific Basin as well as to Hawaiiand all other US interests in the Pacific outside ofAlaska. The West Coast and Alaska TsunamiWarning Center (WC/ATWC) provides servicesto the Gulf of Mexico and Atlantic coasts of theUSA, and to the west and east coasts of Canada.PTWC is also the warning centre for Hawaii'slocal and regional tsunamis. In 2005, the PTWCand JMA began providing interim advisoryservices to the Indian Ocean. The PTWC alsoassists Puerto Rico and the US Virgin Islandswith advisory information, and the WC/ATWCprovides services to the west and east coasts ofCanada.

27

PTWC facilities located at Ewa Beach, Hawaii, USA.

PTWC operations area.

The operational objective of the PTWC is todetect and locate major earthquakes in theregion, to determine if tsunamis were generated,and to provide timely tsunami warnings tonational authorities. To achieve this objective, thePTWC continuously monitors seismic activity andsea levels, and disseminates informationmessages through a variety of communicationsmethods. The PTWC and the WC/ATWC areoperated by the US NOAA National WeatherService. (http://www.prh.noaa.gov/ptwc)(http://wcatwc.arh.noaa.gov/)

activities in the Pacific. Administratively,participating nations are organized under the IOCas the ICG/PTWS with the ITIC acting as thePTWS Secretariat and the PTWC acting as theoperational headquarters for tsunami warning.Among the most important activities of the PTWSis the detection and location of majorearthquakes in the Pacific region, thedetermination of whether they have generatedtsunamis, and the provision of timely andeffective tsunami information and warnings tocoastal communities in the Pacific to minimizethe hazards of tsunamis, especially to human lifeand welfare. To achieve this objective requiresthe national participation and contribution ofmany seismic, sea level, communication, anddissemination facilities throughout the PacificRegion.

SAMPLE: Expanding Regional Tsunami Warning

and Watch (initial)

TSUNAMI BULLETIN NUMBER 001PACIFIC TSUNAMI WARNING CENTER/NOAA/NWSISSUED AT 1819Z 25 FEB 2005

THIS BULLETIN IS FOR ALL AREAS OF THE PACIFICBASIN EXCEPT ALASKA - BRITISH COLUMBIA -WASHINGTON - OREGON - CALIFORNIA.

... A TSUNAMI WARNING AND WATCH ARE IN EFFECT

...

ATSUNAMI WARNING IS IN EFFECT FOR

RUSSIA/ JAPAN / MARCUS IS. / MIDWAY IS. / WAKE IS. /N. MARIANAS / MARSHALL IS. / GUAM / HAWAII /JOHNSTON IS. / CHUUK / POHNPEI / TAIWAN / KOSRAE/ YAP / PHILIPPINES / BELAU / NAURU / KIRIBATI /SAMOA / AMERICAN SAMOA / FIJI / MEXICO / HONGKONG / NEW CALEDONIA / COOK ISLANDS / FR.POLYNESIA

REGIONAL EXPANDING TSUNAMIWATCH/WARNING BULLETIN (RWW)

A message issued initially using only seismicinformation to alert countries of the possibility of atsunami and advise that a tsunami investigationis underway. In the Pacific, Tsunami Warningstatus will encompass regions having less thanthree hours until the estimated time of tsunamiarrival. Those areas having three to six hours willbe placed in a Watch status. Additional bulletinswill be issued hourly or sooner until either aPacific-wide tsunami is confirmed or no furthertsunami threat exists.

28

PTWS

Pacific Tsunami Warning and Mitigation System.The PTWS is an international programme forcoordination of tsunami warning and mitigation

Sea level network used by PTWC to monitor Pacific sealevels. Circles show coastal sea level stations and trianglesshow NOAA DART systems. Colors indicate responsibleagency: PTWC (dark blue), NOAA National Ocean Service(green), Univ of Hawaii Sea Level Center (red), SHOA (bluegreen), JMA (pink), Russian Hydromet (brown), AustraliaNational Tidal Center (light blue), WC/ATWC (yellow),NOAANational Data Buoy Center (orange).

Global seismic network used by PTWC to monitor

seismicity.

PTWC GLOBAL SEISMOGRAPHIC NETWORK

A TSUNAMI WATCH IS IN EFFECT FOR

NEW ZEALAND / EL SALVADOR / NICARAGUA

FOR ALL OTHER PACIFIC AREAS, THIS MESSAGE ISANADVISORY ONLY.



EVALUATION

IT IS NOT KNOWN THATATSUNAMI WAS GENERATED.THIS WARNING IS BASED ONLY ON THEEARTHQUAKE EVALUATION. AN EARTHQUAKE OFTHIS SIZE HAS THE POTENTIAL TO GENERATE ADESTRUCTIVE TSUNAMI THAT CAN STRIKECOASTLINES NEAR THE EPICENTRE WITHINMINUTES AND MORE DISTANT COASTLINES WITHINHOURS. AUTHORITIES SHOULD TAKE APPROPRIATEACTION IN RESPONSE TO THIS POSSIBILITY. THISCENTER WILL MONITOR SEA LEVEL DATA FROMGAUGES NEAR THE EARTHQUAKE TO DETERMINEIF A TSUNAMI WAS GENERATED AND ESTIMATE THESEVERITY OF THE THREAT.

ESTIMATED INITIAL TSUNAMI WAVE ARRIVAL TIMES.ACTUALARRIVAL TIMES MAY DIFFER AND THE INITIALWAVE MAY NOT BE THE LARGEST. THE TIMEBETWEEN SUCCESSIVE TSUNAMI WAVES CAN BEFIVE MINUTES TO ONE HOUR.


THIS BULLETIN IS FOR ALL AREAS OF THE PACIFICBASIN EXCEPTALASKA - BRITISH COLUMBIA - WASHINGTON -OREGON - CALIFORNIA.

... TSUNAMI WARNINGAND WATCH CANCELLATION ...

THE TSUNAMI WARNING AND WATCH ARECANCELLED FOR ALL COASTAL AREAS AND ISLANDSIN THE PACIFIC.



SAMPLE: Expanding Regional Tsunami Warningand Watch (cancellation)



50.7N 156.1E 2042Z 0.12M 64MINTIME - TIME OF THE MEASUREMENTAMPL - AMPLITUDE IN METERS FROM MIDDLE

TO CREST OR MIDDLE TO TROUGH ORHALF OF THE CREST TO TROUGH

PER - PERIOD OF TIME FROM ONE WAVECREST TO THE NEXT

EVALUATION

SEA LEVEL READINGS INDICATE A TSUNAMI WASGENERATED. IT MAY HAVE BEEN DESTRUCTIVEALONG COASTS NEAR THE EARTHQUAKEEPICENTRE. FOR THOSE AREAS WHEN NO MAJORWAVES ARE OBSERVED FOR TWO HOURS AFTERTHE ESTIMATED TIME OF ARRIVAL OR DAMAGINGWAVES HAVE NOT OCCURRED FOR AT LEAST TWOHOURS THEN LOCAL AUTHORITIES CAN ASSUMETHE THREAT IS PASSED. DANGER TO BOATS ANDCOASTAL STRUCTURES CAN CONTINUE FORSEVERAL HOURS DUE TO RAPID CURRENTS. ASLOCAL CONDITIONS CAN CAUSE A WIDE VARIATIONIN TSUNAMI WAVE ACTION THE ALL CLEARDETERMINATION MUST BE MADE BY LOCALAUTHORITIES.

NO TSUNAMI THREAT EXISTS FOR OTHER COASTALAREAS IN THE PACIFIC ALTHOUGH SOME OTHERAREAS MAY EXPERIENCE SMALL SEA LEVELCHANGES FOR ALL AREAS THE TSUNAMI WARNINGAND TSUNAMI WATCHARE CANCELLED.

THIS WILL BE THE FINAL BULLETIN ISSUED FOR THISEVENT UNLESS ADDITIONAL INFORMATIONBECOMESAVAILABLE.

REGIONAL FIXED TSUNAMI WARNING

BULLETIN

A message issued initially using only seismicinformation to alert all participants of thepossibility of a tsunami and advise that a tsunamiinvestigation is underway. The area placed in aTsunami Warning status encompasses coastalregions within 1,000 km of the earthquakeepicentre. A Regional Fixed Tsunami Warningwill be followed by additional bulletins withoutexpanding the warning area until it is eitherupgraded or is cancelled.

29

SAMPLE: Fixed Regional Tsunami Warning

(initial)


...ATSUNAMI WARNING IS IN EFFECT ...

A TSUNAMI WARNING IS IN EFFECT FORRUSSIA

FOR ALL OTHER PACIFIC AREAS, THIS MESSAGE ISANADVISORY ONLY.


ORIGIN TIME - 25 FEB 2005COORDINATES - 52.3 NORTH 160.7 EASTLOCATION - OFF EAST COAST OF KAMCHATKAMAGNITUDE - 7.7

EVALUATION

IT IS NOT KNOWN THATATSUNAMI WAS GENERATED.THIS WARNING IS BASED ONLY ON THEEARTHQUAKE EVALUATION. AN EARTHQUAKE OFTHIS SIZE HAS THE POTENTIAL TO GENERATE ADESTRUCTIVE TSUNAMI THAT CAN STRIKECOASTLINES IN THE REGION NEAR THE EPICENTREWITHIN MINUTES TO HOURS. AUTHORITIES IN THEREGION SHOULD TAKE APPROPRIATE ACTION INRESPONSE TO THIS POSSIBILITY. THIS CENTER WILLMONITOR SEA LEVEL GAUGES NEAREST THEREGION AND REPORT IF ANY TSUNAMI WAVEACTIVITY IS OBSERVED. THE WARNING WILL NOTEXPAND TO OTHER AREAS OF THE PACIFIC UNLESSADDITIONAL DATA ARE RECEIVED TO WARRANTSUCHAN EXPANSION.

ESTIMATED INITIAL TSUNAMI WAVE ARRIVAL TIMES.ACTUALARRIVALTIMES MAY DIFFERAND THE INITIALWAVE MAY NOT BE THE LARGEST. THE TIMEBETWEEN SUCCESSIVE TSUNAMI WAVES CAN BEFIVE MINUTES TO ONE HOUR.

TSUNAMI BULLETIN NUMBER 001PACIFIC TSUNAMI WARNINGCENTER/NOAA/NWSISSUEDAT 1819Z 25 FEB 2005

1804Z

LOCATION COORDINATES ARRIVALTIME-----------------------------------------------------------------------RUSSIA

PETROPAVLOVSK-K 52.9N 158.3E 1926Z 25 FEBUST KAMCHATSK 56.2N 162.5E 1943Z 25 FEBMEDNNY IS 54.6N 167.6E 1946Z 25 FEBSEVERO KURILSK 50.6N 156.3E 2000Z 25 FEBURUP IS 45.9N 150.2E 2031Z 25 FEB

BULLETINS WILL BE ISSUED HOURLY OR SOONER IFCONDITIONS WARRANT.

THE TSUNAMI WARNING WILL REMAIN IN EFFECTUNTILFURTHER NOTICE.



... TSUNAMI WARNING CANCELLATION ...

THE TSUNAMI WARNING IS CANCELLED FOR ALLCOASTALAREASAND ISLANDS IN THE PACIFIC.





50.7N 156.1E 2042Z 0.12M 64MIN

SAMPLE: Fixed Regional Tsunami Warning(cancellation)

TSUNAMI BULLETIN BOARD (TBB)

TBB is an ITIC-sponsored e-mail service thatprovides an open, objective scientific forum forthe posting and discussion of news andinformation relating to tsunamis and tsunamiresearch. The ITIC provides the service totsunami researchers and other technicalprofessionals for the purpose of facilitating thewidespread dissemination of information ontsunami events, current research investigations,and announcements for upcoming meetings,publications, and other tsunami-relatedmaterials.All members of the TBB are welcome tocontribute. Messages are immediately broadcastwithout modification. The TBB has been veryuseful for helping to rapidly organize post-tsunami surveys, for distributing their results, andfor planning tsunami workshops and symposia.Members of the TBB automatically receive thetsunami bulletins issued by the PTWC,WC/ATWC, and JMA.

30

TSUNAMI INFORMATION BULLETIN (TIB)

SUNAMI RESPONSE PLAN (TRP)T

TWC message product advising the occurrenceof a major earthquake with an evaluation thatthere is either: a) no widespread tsunami threatbut the small possibility of a local tsunami or b)there is no tsunami threat at all that indicatesthere is no tsunami threat.

The Tsunami Response Plan describes theactions taken to ensure public safety byresponsible agencies after notification by theTsunami Warning Focal Point (TWFP), typicallythe national Tsunami Warning Centre. It includesStandard Operating Procedures and Protocolsfor emergency response and act ion,organizations and individuals involved and their

SAMPLE: Tsunami Information Bulletin (shallow

undersea event)



... TSUNAMI INFORMATION BULLETIN ...

THIS MESSAGE IS FOR INFORMATION ONLY. THEREIS NO TSUNAMI WARNING OR WATCH IN EFFECT.


ORIGIN TIME - 25 FEB 2005COORDINATES - 52.3 NORTH 160.7 EASTLOCATION - OFF EAST COAST OF KAMCHATKAMAGNITUDE - 6.7

EVALUATION

NO DESTRUCTIVE PACIFIC-WIDE TSUNAMI THREATEXISTS BASED ON HISTORICAL EARTHQUAKE ANDTSUNAMI DATA.

HOWEVER - EARTHQUAKES OF THIS SIZESOMETIMES GENERATE LOCAL TSUNAMIS THAT CANBE DESTRUCTIVE ALONG COASTS LOCATED WITHINA HUNDRED KILOMETERS OF THE EARTHQUAKEEPICENTRE. AUTHORITIES IN THE REGION OF THEEPICENTRE SHOULD BE AWARE OF THISPOSSIBILITYAND TAKEAPPROPRIATEACTION.

THIS WILL BE THE ONLY BULLETIN ISSUED FOR THISEVENT UNLESS ADDITIONAL INFORMATIONBECOMESAVAILABLE.

1804Z

roles and responsibilities, contact information,timeline and urgency assigned to action, andmeans by which both ordinary citizens andspecial needs populations (physically or mentallyhandicapped, elderly, transient, and marinepopulations) will be alerted. For tsunamiresponse, emphasis is placed on the rapidness,efficiency, conciseness, and clarity of the actionsand instructions to the public. A TsunamiResponse Plan should also include post-tsunamiactions and responsibilities for search andrescue, relief, rehabilitation, and recovery.

The highest level of tsunami alert. Warnings areissued by the TWCs due to confirmation of adestructive tsunami wave or the threat of animminent tsunami. Initially the warnings arebased only on seismic information withouttsunami confirmation as a means of providing theearliest possible alert to at-risk populations.Warnings initially place a restricted area in acondition that requires all coastal areas in theregion to be prepared for imminent flooding.Subsequent text products are issued at leasthourly or as conditions warrant to continue,expand, restrict, or end the warning. In the eventa tsunami has been confirmed which could causedamage at distances greater than 1,000 km fromthe epicentre, the warning may be extended to alarger area.

Centre that issues timely tsunami informationmessages. The messages can be information,watch, or warning messages, and are based onthe available seismological and sea level data asevaluated by the TWC, or on evaluationsreceived by the TWC from other monitoringagencies. The messages are advisory to theofficial designated emergency responseagencies. Regional TWCs monitor and providetsunami information to Member States onpotential ocean-wide tsunamis using global datanetworks, and can often issue messages within10-20 minutes of the earthquake. Local TWCsmonitor and provide tsunami information onpotential local tsunamis that will strike withinminutes. Local TWCs must have access tocontinuous, real-time, densely-spaced data

T

T

SUNAMI WARNING

SUNAMI WARNING CENTRE (TWC)

31

networks in order to characterize theearthquakes within seconds and issue a warningwithin minutes.

An example of a Regional Tsunami WarningCentre is the Pacific Tsunami Warning Center,which provides international tsunami warnings tothe Pacific. After the 26 December 2005 tsunami,the PTWC and JMA has acted as an InterimRegional TWC for the Indian Ocean.

Examples of sub-regional TWCs are theNWPTAC operated by the Japan JMA,WC/ATWC operated by the US NOAA NWS, andCPPT operated by France. These centres, alongwith Russia and Chile, also act as national TWCsproviding local tsunami warnings for theircountries.

.

Tsunami Warning Centres issue four basic typesof messages: 1) information bulletins when alarge earthquake has occurred but there is little orno tsunami threat; 2) regional watch and warningbulletins when there is a potential threat of adestructive tsunami; 3) ocean-wide warningbulletins when there is confirmation of tsunamiwaves capable of widespread tsunamidestruction beyond the local area; and 4) tsunamicommunication test messages to regularlyexercise the system. Initial evaluations andmessages are based only on the faster arrivingseismic information, specifically earthquakelocation, magnitude, and depth. If a tsunamithreat is possible, estimated tsunami wave arrivaltimes are calculated and sea level records areexamined to confirm whether a tsunami has beengenerated. Watch and Warning bulletins areupdated hourly until the threat is gone. In thePacific, the types of messages issued by thePTWC include a Pacific-Wide Tsunami WarningBulletin, Regional Expanding Tsunami Warningand Watch Bulletin, Regional Fixed TsunamiWarning Bulletin, Tsunami Information Bulletin,and Tsunami Communication Test DummyMessage.

The second highest level of tsunami alert.Watches are issued by the Tsunami Warning

T

T

SUNAMI WARNING CENTRE PRODUCTS

SUNAMI WATCH

Centres (TWCs) based on seismic informationwithout destructive tsunami confirmation. Thewatch is issued as a means of alerting theaffected populations located, for example, one tothree hours tsunami travel time beyond thewarned area. Subsequent text products areissued at least hourly to expand the watch andwarning area, upgrade all areas to a warning, orend the watch and warning. A Tsunami Watchmay be included in the text of the message thatdisseminates a Tsunami Warning.

UNESCO

WDC

United Nations Educational, Scientific andCultural Organization. Established in 1945,UNESCO promotes international cooperationamong its Member States in the fields ofeducation, science, culture and communication.Today, UNESCO works as a laboratory of ideasand standard setter to forge universalagreements on emerging ethical issues. TheOrganization also serves as a clearinghouse thatdisseminates and shares information andknowledge, while helping Member States to buildtheir human and institutional capacities in diversefields. The UNESCO Constitution states, “Sincewars begin in the minds of men, it is the minds ofmen that the defen es of peace must beconstructed.”

World Data Center. The WDC system wascreated to archive and distribute data collectedfrom the observational programmes of the 1957-1958 International Geophysical Year. Originallyestablished in the United States, Europe, Russia,and Japan, the WDC system has since expandedto other countries and to new scientificdisciplines. The WDC system now includes 52Centres in 12 countries. Its holdings include awide range of solar, geophysical, environmental,and human dimensions data. These data covertime scales ranging from seconds to millenniaand they provide baseline information forresearch in many disciplines. Tsunamis arecollected by the WDC for Solid Earth Geophysics.The WDC-SEG is co-located with the US NOAAN a t i o n a l G e o p h y s i c a l D a t a C e n t e r.

s

(http://www.unesco.org/bpi)

(http://www.ngdc.noaa.gov/wdc/wdcmain.html)

32

BIBLIOGRAPHY66GENERAL

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Dudley, M. and M. Lee, Tsunami! 2 Ed.,Honolulu: University of Hawaii Press, 1998.

Iida, K., Catalog of tsunamis in Japan and itsneighboring countries. Special Report,Yashigasa, Yakusa-cho, Toyota-shi: AichiInstitute of Technology, 1984.

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UNESCO-IOC International Tsunami InformationCentre. Tsunami: The Great Waves IOCBrochure 2005. Paris, UNESCO, 2005.

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UNESCO-IOC International Tsunami InformationCentre. Tsunami Warning!, IOC Brochure 2005.Paris, UNESCO, 2005.

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In English; Spanish, Frenchand Russian version also online.

.In

English; Spanish and French earlier version alsoonline.

Earlier revision in Spanish and French.

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Berninghausen, W.H., Tsunamis and seismicseiches reported from regions adjacent to theIndian Ocean. Bulletin of the SeismologicalSociety ofAmerica, Feb.1966; 56(1):69-74.

Berninghausen, W.H., Tsunamis and seismicseiches reported from the Western North andAtlantic and the coastal waters of NorthwesternEurope. Informal Report No. 68-05, WashingtonDC: Naval Oceanographic Office, 1968.

Berninghausen, W.H., Tsunamis reported fromthe west coast of South America, 1562-1960.Bull. Seismol. Soc. Amer., 52, 915-921, 1962.

Berninghausen, W. H., Tsunamis and seismicseiches reported from the eastern Atlantic southof the Bay of Biscay. Bull. Seismol. Soc. Amer.,54, 439-442, 1964.

Dunbar, P.K., P. A. Lockridge, and L. S.Whiteside, Catalogue of Significant Earthquakes2150BC1991AD. US Department of Commerce,NOAA, National Geophysical Data Center,Boulder, USA, World Data Center A for SolidEarth Geophysics Reports SE-49, 320 pp, 1992.

Everingham, I.B., Preliminary Catalogue ofTsunamis for the New Guinea I Solomon IslandRegion 1768-1972. Bureau of MineralResources, Canberra, Australia, Report 180, 78pp, 1977.

Iida, K., D. Cox, and G. Pararas-Carayannis,Preliminary catalog of tsunamis occurring in thePacific Ocean. Data Report No. 5, HawaiiInstitute of Geophysics, HIG-67-10. Honolulu:University of Hawaii, 1972. URL:

, Versions in Russian,

French and Spanish. English and Spanish

versions available online through ITIC Web Site.

EVENT CATALOGUES

re-issuedhttp://www.soest.hawaii.edu/Library/Tsunami%20Reports/Iida_et_al.pdf

33

Pararas-Carayannis, G., Catalogue of Tsunamisin the Hawaiian Islands. US Department ofCommerce, NOAA National Geophysical Center,Boulder, USA, World Data Center A for SolidEarth Geophysics Publication, 94 pp, 1969.

Lander, J.F, P.A. Lockridge, and M.J. Kozuch,Tsunamis affecting the West Coast of the UnitedStates 1806-1992. US Department ofCommerce, NOAA, National Geophysical DataCenter, Boulder, USA, NGDC Key toGeophysical Records Documentation KGRD-29.December 1993, 242 pp, 1993.

Lander, J., and P. Lockridge, United StatesTsunamis (including United States Possessions)1690-1988. Publication 41-2, Boulder: NationalGeophysical Data Center, 1989.

Lockridge, P.A. and R. H. Smith, 1984 : Map ofTsunamis in the Pacific Basin, 1900-1983. Scale1:17,000,000. US NOAA National GeophysicalData Center World Data Centre A For SolidEarth Geophysics and Circum-Pacific Council forEnergy and Minteralo Resources Map Project.

Mol ina, E.e (Seccion de Sismologia,INSIVUMEH, Guatemala). Tsunami cataloguefor Central America 1539-1996 [Report].Reduction of natural disasters in CentralAmerica. Universitas Bergensis TechnicalReport no. II 1-04, Bergen, Norway: Institute ofSolid Earth Physics, University of Bergen; 1997.

O'Loughlin, K.F. and J.F. Lander, Caribbeantsunamis: A 500-year history from 1498-1998,Advances in Natural and Technological HazardsResearch; v. 20 Boston, MA: Kluwer AcademicPublishers; 2003.

Soloviev, S.L., et al., Tsunamis in theMediterranean Sea 2000 BC-2000AD.Advancesin Natural and Technological Hazards Research,Vol. 13, Dordrecht: Kluwer Academic Publishers,2000.

Soloviev, S.L., and C. N. Go, A catalogue oftsunamis on the western shore of the PacificOcean. Academy of Sciences of the USSR,Nauka Publishing House, Moscow, 310 p.[Canadian Translation of Fisheries and AquaticSciences No. 5077, 1984, translation availablefrom Canada Institute for Scientific and TechnicalInformation, National Research Council, Ottawa,Ontario, Canada K1A OS2, 447 p., 1974]

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Soloviev, S.L., and C. N. Go, A catalogue oftsunamis on the eastern shore of the PacificOcean. Academy of Sciences of the USSR,Nauka Publishing House, Moscow, 204 p.[Canadian Translation of Fisheries and AquaticSciences No. 5078, 1984, translation availablefrom Canada Institute for Scientific and TechnicalInformation, National Research Council, Ottawa,Ontario, Canada K1A OS2, 293 p., 1975]

Soloviev, S.L., C. Go, and C. S. Kim, Catalogueof Tsunamis in the Pacific 1969-1982, Results ofResearches on the International GeophysicalProjects. Moscow: Academy of Sciences of theUSSR, 1992.

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Ambraseys, N.N., Data for the investigation ofthe seismic sea-waves in the EasternMediterranean, Bulletin of the SeismologicalSociety of America, 52:4 (Oct 1962), pp. 895-913.

Dmowska, R. and B. Saltzman, eds.,Tsunamigenic ear thquakes and the i rconsequences. Advances in Geophysics, Vol.39, San Diego: Academic Press, 1998.

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Hatori, T., Relation between tsunami magnitudeand wave energy, Bull. Earthquake Res. Inst.Univ. Tokyo, 54, 531-541 (in Japanese withEnglish abstract), 1979.

TECHNICAL

35

Hatori, T., Classification of tsunami magnitudescale, Bull. Earthquake Res. Inst. Univ. Tokyo,61, 503-515 (in Japanese with English abstract),1986.

Iida, K. and T. Iwasaki, eds., Tsunamis: Theirscience and engineering, Proceedings of theInternational Tsunami Symposium (1981),Tokyo: Terra Scientific, 1983.

Kanamori, H., “Mechanism of tsunamiearthquakes,” Phys. Earth Planet. Inter., 6, pp.346-359, 1972.

Keating, B., Waythomas, C., and A. Dawson,eds., Landslides and Tsunamis. Pageoph TopicalVolumes, Basel: Birhäuser Verlag, 2000.

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Papadopoulus, G., and F. Imamura, “A proposalfor a new tsunami intensity scale,” InternationalTsunami Symposium Proceedings, Session 5,Number 5-1, Seattle, 2001.

Satake, K., ed., Tsunamis: Case studies andrecent developments. Dordrecht: Springer,2005.

Satake, K. and F. Imamura, eds., Tsunamis1992-1994: Their generation, dynamics, andhazard, Pageoph Topical Volumes. Basel:Birhäuser Verlag, 1995.

Sauber, J. and R. Dmowska, Seismogenic andtsunamigenic processes in shallow subductionzones. Pageoph Topical Volumes, Basel:Birhäuser Verlag, 1999.

Shuto, N., “Tsunami intensity and disasters,” inTsunamis in the World edited by S. Tinti,Dordrecht: Kluwer Academic Publishers, pp.197-216, 1993.

Sieberg, A., Erdbebenkunde, Jena: Fischer,1923. (Sieberg’s scale, pp. 102-104.)

Soloviev, S.L., “Recurrence of earthquakes andtsunamis in the Pacific Ocean,” in Tsunamis inthe Pacific Ocean, edited by W. M. Adams,Honolulu: East-West Center Press, pp. 149-164,1970.

nd

Soloviev, S.L., “Recurrence of earthquakes andtsunamis in the Pacific Ocean,” Volny Tsunami(Trudy SahkNII, Issue 29), Yuzhno-Sakhalinsk,pp. 7-46, 1972 (in Russian).

Tinti, S., ed., Tsunamis in the World : FifteenthInternational Tsunami Symposium, 1991,Advances in Natural and Technological HazardsResearch, Vol. 1. Dordrecht: Kluwer AcademicPublishers, 1993.

Tsuchiya, Y. and N. Shuto, eds., Tsunami:Progress in prediction, disaster prevention andwarning. Advances in Natural and TechnologicalHazards Research, Vol. 4. Dordrecht: KluwerAcademic Publishers, 1995.

Yeh, H., Liu, P., and C. Synolakis, Long-waverunup models, Singapore: World Scientific, 1996.

Pre-elementary school: Earthquakes andtsunamis Chile: SHOA/IOC/ITIC, 1996. Revised2003 in Spanish.

2-4 Grade: I invite you to know the earth I. Chile:SHOA/IOC/ITIC, 1997.

5-8 Grade: I invite you to know the earth II. Chile:SHOA/IOC/ITIC, 1997.

High School: Earthquakes and tsunamis. Chile:SHOA/IOC/ITIC, 1997.

TEXTBOOKS AND TEACHERS

GUIDEBOOKS (in English and Spanish)

36

Air-coupled tsunami 2Arrival time 16Atmospheric tsunami 2Breaker 7Breakwater 7Communications Plan 24

for the Tsunami Warning System

Deep-ocean tsunami detection 21system (DART)

Drop 16Eddy 7Elapsed time 16Estimated time of arrival (ETA) 8Evacuation map 8Forecast Point 24GLOOS 24GOOS 24GTS 24Historical tsunami 2Historical tsunami data 8ICG 24ICG/CARIBE-EWS 25ICG/IOTWS 25ICG/ITSU 25ICG/NEAMTWS 25ICG/PTWS 25

ICG Tsunami National 25

Initial rise 16Intensity 16Inundation 16

Inundation area 16Inundation line 17IOC 25ITIC 26IUGG 26JMA 26Leading wave 17Local tsunami 2Low water 21

Magnitude 17

Mareogram 21Mareograph 21

Master Plan 26Mean height 17Mean sea level 21Microtsunami 2Ocean-wide tsunami 2Ocean-wide tsunami warning 26Overflow 17Paleotsunami 2Post-tsunami survey 17Probable maximum water level 22PTWC 27PTWS 28Recession 18Reference sea level 22Refraction diagrams 22Regional tsunami 3Regional Expanding Tsunami 28

Watch/Warning Bulletin (RWW)Regional Fixed Tsunami 29

Warning BulletinRise 18Runup 18Runup distribution 18Sea level 22Sea level station 22Seiche 8Seismic sea wave 8Sieberg tsunami intensity scale 18Significant wave height 19Spreading 19Subsidence (uplift) 19Teletsunami or distant tsunami 4Tidal wave 23Tide 23Tide amplitude 23Tide gauge 23Tide station 23Travel time 8Travel time map 8Tsunameter 23

Tsunami 6Tsunami amplitude 19Tsunami bore 9Tsunami Bulletin Board (TBB) 30Tsunami damage 9Tsunami dispersion 10Tsunami earthquake 6Tsunami edge wave 10Tsunami forerunner 10Tsunami generation 10Tsunami generation theory 11Tsunami hazard 11Tsunami hazard assessment 11Tsunami impact 11Tsunami Information Bulletin (TIB) 31Tsunami intensity 20Tsunami magnitude 20Tsunami numerical modelling 12Tsunami observation 13Tsunami period 20Tsunami period (dominant) 20Tsunami preparedness 13Tsunami propagation 14Tsunami resonance 14Tsunami Response Plan (TRP) 31Tsunami risk 14Tsunami sediments 6Tsunami simulation 14Tsunami source 15

Tsunami Warning 31Tsunami Warning Centre (TWC) 31Tsunami Warning Centre Products 32Tsunami Watch 32Tsunami wave length 20Tsunami zonation 15Tsunamic 15Tsunamigenic 15UNESCO 32Water level (maximum) 20Wave crest 20Wave trough 20WDC 32

Cotidal 21Crest length 16

ICG Tsunami Warning 25Focal Point (TWFP)

Contact (TNC)

Inundation (maximum) 16

Maremoto 2

Marigram 21

Tsunami velocity or shallow water 15velocity

Located in Honolulu, the International Tsunami Information Centre (ITIC) was established on 12 November 1965 by theIntergovernmental Oceanographic Commission (IOC) of the United Nations Educational, Scientific, and CulturalOrganization (UNESCO). The first session of the International Coordination Group for the Tsunami Warning System in thePacific (ITSU) convened in 1968. In 2005, the ITSU was renamed as the Intergovernmental Coordination Group for thePacific Tsunami Warning and Mitigation System (ICG/PTWS) to emphasize the comprehensive nature of risk reduction.

The ITIC thanks the following scientists for their assistance and helpful review of this document: Fumihiko Imamura, ModestoOrtiz, Kenji Satake, François Schindele, Fred Stephenson, Costas Synolakis, and Masahiro Yamamoto.

Phone: <1> 808-532-6422Fax: <1> 808-532-5576

E-mail: [email protected]

737 Bishop Street Suite 2200Honolulu, Hawaii 96813-3213, U.S.A.

http://www.tsunamiwave.info

INDEX77

I T I CNTERNATIONAL SUNAMI NFORMATION ENTRE (ITIC)

Intergovernmental Oceanographic Commission (IOC)United Nations Educational, Scientific and Cultural Organization (UNESCO)1, rue Miollis75 735 Paris Cedex 15FranceTel : +33 1 45 68 39 83Fax : +33 1 45 68 58 12http://ioc.unesco.org

International TsunamiInformation Centre

IntergovernmentalOceanographicCommission

GLOSSARY

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Tsunami Glossary - Version 12

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