D.2.1_Current Availability and Methodology for Natural Risk Map Production.pdf EXELENTE USAR PARA...

7/22/2019 D.2.1_Current Availability and Methodology for Natural Risk Map Production.pdf EXELENTE USAR PARA DALA

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ARMONIA PROJECT (Contract n 511208)

APPLIED MULTI-R ISK M APPING OF N ATURAL H AZARDSFOR IMPACT ASSESSMENT

DELIVERABLE 2.1

Report on current availability and methodology for natural risk mapproduction

Zuzana Boukalova, Jakub Heller

Ceske Centrum pro Strategicka Studia (CCSS), Water Management Department


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Report on current availability and methodology

for natural risk map production (Del. 2.1)OverviewDel. 2.1 collected the state-of-art for individual natural risk assessmentmethodologies for different risk categories applied either by scientificcommunity or administrative end-users. Considered risks were:

o Floodso Earthquakeso Landslideso Forest fireso Volcanic activitieso Meteorological extreme events and climate change, as well aso Possible secondary effects of natural hazard discussed by the

example of groundwater pollution.

The report on the results of the analysis consists of an introduction, thecollection of the state-of-the art for risk assessment methodologies for eachidentified natural event, and a summary of state-of-the art of currentmethodologies for individual risk assessment methodologies for differentrisk categories.

Each singular report on a natural event is following a common structure.

The goal of the proposed research activity was to be the basis for the

f th h th h i ti f i ti th d l i d t


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ARMONIA PROJECT

Contract n 511208

WP2: Collection and evaluation of currentmethodologies for risk map production


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ARMONIA PROJECT (Contract n 511208) Deliverable 2.1

Contract Number: 511208Project Acronym: ARMONIA

Title:

Applied multi Risk Mapping of Natural Hazards for Impact Assessment

Deliverable N: 2.1Due date : 30th May 2005

Delivery date: 7th June 2005

Short Description:

Del. 2.1 is collecting the state-of-art for individual natural risk assessmentmethodologies for different risk categories applied either by scientificcommunity or administrative end-users. Considered risks are: floods,earthquakes, landslides, forest fires, volcanic activities, meteorologicalextreme events and climate change, as well as possible secondary effectsof natural hazard discussed by the example of groundwater pollution.

Partners owning: CR4 (CCSS)


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Table of contents

A. INTRODUCTION

B. STATE-OF-T HE-ART FOR INDIVIDUAL RISKSASSESSMENT METHODOLOGIES FOR DIFFERENT RISKCATEGORIES

B.I Floods

B.II Earthquakes

B.III Landslides

B.IV Forest fireB.V Volcanoes

B.VI. Meteorological extreme events and climatechange

B.VII Possible secondary effects of natural hazardsas example of groundwater pollution


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A. Introduction

The main goal of WP 2 was to analyse the state-of-the art for individualrisks assessment methodologies for different risk categories.

The following natural events were studied, selected according to theirdiffusion and importance throughout Europe:

Floods Earthquakes Landslides Forest fire Volcanoes Meteorological extreme events and climate change Possible secondary effects of natural hazards as example of

groundwater pollution

Deliverable 2.1 reports on the results of the analysis and consists of thefollowing three main parts:

o Part A: Introduction

P B C ll i f h f h f i k


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infrastructure and environmental features in the area potentially affectedby risk)

Typology of elements Definition of exposure

Analysis of vulnerability (Characteristic of a system that describes itspotential to be harmed. This can be considered as a combination of susceptibility and value)

Definition of vulnerability and/or consequence Methodologies for assessment related to structural and non-

structural elements at risk

Analysis of risk (a methodology to objectively determine risk by combiningprobabilities and consequences or, in other words, combining hazards andvulnerabilities).

Definition of risk

Methodologies for risk analysis assessment Examples of risks maps and legends Risk managament

Appendix:

Minimum standard (simplified model) for hazard mapping aimed at a legaldirective


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the Hazard approach, is developed at local scale (ranging from1/2,000 to 1/10,000): the probability that a specific event may

occur in a given area within a given time window. the Site Engineering approach, is developed at site scale (ranging

from 1/100 to 1/1000): suited to direct the work needed to reducerisk.

The goal of the proposed research activity was to be the basis for thefurther research on the harmonisation of existing methodologies,data availability, technological tools and outputs , for the benefit of end users, achieving a practical result that can optimise the deployment of resources (financial, human, technological) and improve disastermitigation and prevention. A risk assessment process for each naturalhazard event was defined, always in the view of its integration into landplanning.


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B. STATE-OF-THE-ART FOR INDIVIDUAL

RISKS ASSESSMENT METHODOLOGIESFOR DIFFERENT RISK CATHEGORIES


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B.I Floods

Author: Darren Lumbroso, HRW

1 Definition of floods .................................................. 4

1.1 Typologies....................................................................... 4

1.2 Flood magnitude, intensity and severity.............................. 4

1.2.1 Annual probability of exceedence ............................................ 4

1.2.2 Return period ....................................................................... 6

2 Hazard assessment.................................................. 6

2.1 Definition of flood hazard .................................................. 6

2.2 Current methods for analysing and representation of hazardwith respect to temporal scales............................................... 6

2.2.1 Background .......................................................................... 6


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2.6 Data typology, format and availability .............................. 11

2.6.1 Fluvial floods ...................................................................... 122.6.2 Coastal floods ..................................................................... 12

2.7 Examples of flood hazard maps........................................ 12

3 Elements at risk and exposure ............................... 18

3.1 Typology of elements ..................................................... 18

3.2 Definition of exposure..................................................... 18

4 Analysis of vulnerability ........................................ 19

4.1 Definition of vulnerability and/or consequence ................... 19

4.2 Methodologies for assessment related to structural and non-structural elements at risk............................................... 19

4.2.1 Assessment for structural elements - economic damage to properties .......................................................................... 19

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5.4.2 Functions of risk analysis ..................................................... 29

5.4.3 Examples of risk maps and legends....................................... 35

6 Risk management.................................................. 38

6.1 Generic risk management options .................................... 38

6.1.1 Controlling the source.......................................................... 38

6.1.2 Controlling the pathway ....................................................... 38

6.1.3 Controlling the exposure ...................................................... 38

6.1.4 Examples of controlling vulnerability ..................................... 38

6.2 Significance of risk ......................................................... 38

7 Glossary of all keywords........................................ 41

8 References ............................................................ 44

Appendix: Operational standards for risk assessmentaimed at spatial planning ........................................... 45

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1 Definition of floodsThe term flood can be defined in many ways. In the context of this report aflood will be defined as a general and temporary condition of partial or complete inundation of dry land caused by the overflow of the boundaries of a water body or by the rapid accumulation of surface water runoff . This canbe put more succinctly as a temporary covering of land by water outside itsnormal confines .

1.1 TypologiesFloods may be classified by their various causes, speed of onset andpotential damage. The following broad categories of flood causes are oftenrecognised:

Flash floods that build up rapidly and lowland or plains floods whichhave a slower and more predictable onset;

Floods from the precipitation in a rainfall event ( pluvial floods ) or fromstored water as snowmelt;

Floods from natural events and those from the failure of flood defenceinfrastructure or dam breaks;

Flooding directly from raised groundwater and the contributionantecedent moisture conditions to increasing runoff rates

Flooding from inadequate surface water drainage in urban areas ( urbanfloods ) and from minor watercourses and roadside ditches;

Tidal surges and other marine conditions leading to coastal and estuarialflooding ( coastal floods ).


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B .I - 5

Table 1.1 Flood typologiesType of flood Type or

frequency of event

Number of properties

affected

Geographic distribution Type of damage

Coastal Winter season 1 to 500?Major towns andcities may givelarger numbers

Coastalfringe/estuary/mappedflood risk zoneFlooding possible over largelengths of coast (forexample 1953 storm)

Inundation damage to buildings and contentsPossible loss of life (in excess of 3,000 in 1953)Campsites and caravan parks particularly vulnerableVehicles written off

River (fluvial) Winter seasonSummer storms 1 to 500?Major towns andcities may givelarger numbers

River floodplainFlooding in one or moreriver catchments at any onetime

Inundation damage to buildings and contents,vehicles written off, possible structural damagePossible loss of life especially in flash floods (forexample Lynmouth, 1952 or Sarno, 1997)Deep flooding possible behind raised defencesCampsites and caravan parks particularly vulnerable

Groundwater Prolonged seasonsof rainfall

Small clusters Certain geologies (forexample limestone, chalk)Outside main river

floodplain

Inundation damage to buildings and contentsespecially basements

Water mainsburst

Any time Small clusters Anywhere Inundation damage to buildings and contentsespecially basements

Sewerage Any time Isolated or Smallclusters

AnywhereOutside main riverfloodplain

Inundation damage to buildings and contentsespecially basements

Storm/highwaydrainage

Intense storms especially insummer

Isolated or Smallclusters

Anywhere adjacent to roadsor urban areas

Inundation damage to buildings and contentsPossibly vehicle accidents


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1.2.2 Return period The return period of a flood describes the frequency with which a particularcondition (for example maximum flow or water level) is, on average, likelyto be equalled or exceeded. It is normally expressed in years and istherefore the reciprocal of the annual exceedence frequency. It is not areciprocal of the annual probability of exceedence although this is areasonable approximation at higher return periods.

For example a 1 in 100 year flood describes a flood event that has aapproximately a 1% annual probability of being equalled or exceeded in anygiven year. This does not mean such a flood will occur only once in onehundred years. Whether or not it occurs in a given year has no bearing onthe fact that there is still about a 1% chance of a similar occurrence in thefollowing year.

2 Hazard assessment

2.1 Definition of flood hazardA hazard may be defined as a situation with the potential to result inharm . A hazard does not necessarily lead to harm, but identification of ahazard does mean that there is a possibility of harm occurring. In thecontext of flooding, a flood hazard exists in areas where flooding can occur.

2.2 Current methods for analysing and representation


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To understand the link between hazard and risk it is useful to consider thecommonly adopted Source-Pathway-Receptor-Consequence model. This is a

simple conceptual tool for representing systems and processes that lead toa particular consequence. For a flood risk to arise there must be floodhazard that consists of a 'source' or initiator event (i.e. high rainfall); a'receptor' (e.g. houses or people in the floodplain); and a pathway betweenthe source and the receptor (e.g. overland flow). This conceptual model isshown in Figure 2.1.

A hazard does not automatically lead to a harmful outcome, butidentification of a hazard does mean that there is a possibility of harm occurring.


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indication of event probability. Raised beaches provide an example of howsoil data can mislead, as these were created by isostatic uplift and may be

several metres above any current flood level.

2.3.3 Aerial photography If a historical flood was particularly large and of sufficient duration to permitmobilisation of aircraft then aerial photography may have been carried outby an organisation with an interest in flooding (for example a rivermanagement organisation or news media). This will provide information onareas that flooded during the particular flood being photographed althoughthe magnitude of the flood (expressed in terms of probability of occurrence)may not be known.

2.3.4 Satellite imagery Microwave and optical satellite imaging of selected river reaches can beused to detect flood conditions and produce flood extents. The limitation of flood maps based on historical events is described above.

2.3.5 Catchment scale modelling Catchment scale hydrological and hydraulic modelling is used whenassessing flood hazard at the scale of a hydrological catchment or riverbasin. This is described in Section 2.4.2.

2.3.6 Detailed hydrological and hydraulic modelling Detailed hydrological and hydraulic modelling is usually used when


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3 Produce a DTM of the country with a sufficiently accurate verticalresolution;

4 Estimate the water level for the defined flood at any point along therivers. This may require the use of a hydraulic model;

5 Use the DTM in combination with the water levels for the definedflood to delineate the flood extent and estimate flood depths. This isusually carried out using a Geographical Information System (GIS).

2.4.2 Regional or catchment scale flood hazard assessment To estimate flood hazard at a catchment or river basin level a catchmentscale model is required. The model should be able to predict water levels atany location in the catchment for a variety of conditions. Water levelsdepend on river flows, which in turn depend on inflows from sub-catchments. The broad scale catchment model must be able to represent:

Rainfall-runoff processes, to predict inflows from sub-catchments; Flood hydrographs throughout the catchment including:

- Attenuation as flood waves move along a river;- Combination of flood hydrographs at confluences and other lateral

inflows; Water levels at selected points in the catchment.

Table 2.1 outlines the modelling methods to estimate catchment floodhazard.


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The upstream and downstream limits of the survey should be defined by theobjectives of the flood hazard assessment. The cross-sections surveyed

should be representative of the watercourse channel and floodplain. Thespacing between cross sections is determined by the nature of thewatercourse (for example width, channel depth, slope). Survey data of anyhydraulically significant structures are also required (for example, weirs,bridges, flood walls).

Step 2 Hydrological assessmentA hydrological assessment of the flood flows should be made usingappropriate methodology and design inflows for the model produced. Theseare usually in the form of a hydrograph.

Step 3 Construction of a hydraulic modelA full hydrodynamic model should be constructed if the area contains eitherstructures whose operation varies with time (for example pumps, sluices,tidal outfalls) or a tidal estuary. In other cases, either a steady-state orhydrodynamic model may be chosen. However, a steady-state hydraulicmodel may give an overestimation of water levels where significant storageis present.

Step 4 Calibration and verification of the modellingWherever practicable, the hydrological assessment and the hydraulic modelshould be calibrated against recorded flows and/or water levels fromobserved flood events. If calibration is carried out, at least one separateobserved event should be run through the model after the calibration to


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Step 3 Flood simulationInundation depth, velocity of flood flow, and flood arrival time in coastal

zones are estimated by numerical simulation, taking the time series data of tide level and wave overtopping rate, and the time of coastal dike failureinto account. A GIS is usually used to map the flood extent and depth.

Figure 2.2 shows a schematic diagram that outlines the method forassessing coastal floods.

Wave

overtopping rate

Coastalflooddike

Inundationdepth

Inundation extent

Tidal level

Setting of tidelevel and waveovertopping rate

Figure 2.2 Example of method used to assess coastal flood extent anddepth


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2.6.1 Fluvial floodsThe type of data required for fluvial flood hazard mapping will varydepending on the scale at which the hazard assessment is being carried outand how the risk is to be quantified. However, key data requirements are asfollows:

Topographic data at a suitable resolution, for example:- Surveyed river cross-sections;- Surveyed floodplain sections;- Photogrametric data or contour maps;- Digital terrain model (DTM);

Hydrological and hydrometric data:- Design and historical rainfall data;- Design and historical river flow data;- Details of hydrological gauging stations;

Surveys of structures that have an impact on floodwater levels ,for example:

- Weirs;- Bridges and culverts;- Dams and reservoirs;- Flood defences and walls;

Calibration and verification data from previous floods , forexample:

- Observed water levels;- Observed flows.


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Source: Reference 2Figure 2.3 Example of a national flood hazard map for the River Thames

in England showing two high return period floods


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Source: Reference 4Figure 2.5 Example of a catchment scale 1 in 100 year flood extent and

depth map using a 50 m x 50 m DTM of the catchment


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LegendProbabil ity of inundation

High

Medium

Low

Source: Reference 6Figure 2.7 Example of a qualitative flood hazard map used in England


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Figure 2.9 Example of a flood extent between Belleville and Villefranche inFrance for a flood that occurred on 27 March 2001 using radar data


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Figure 2.11 Flood extent map for Dresden, Germany based on the 2002floods with a 50 m buffer round the extent


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Source: Reference 8Figure 2.13 Coastal flood map for the Gretna in Scotland

3 Elements at risk and exposure


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4 Analysis of vulnerability

4.1 Definition of vulnerability and/or consequenceVulnerability may be defined as the characteristic of a system that describes its potential to be harmed. This can be considered as acombination of susceptibility and value . Consequence can be defined as

an impact such as economic, social or environmental damage/improvement that may result from a flood. It may be expressed quantitatively (e.g. by. monetary value), by category (e.g. High, Medium,

Low) or descriptively . Vulnerability is often captured in the assessment of the consequences of flooding

The consequences of flooding are usually assessed in terms of thefollowing:

Economic damage to assets, for example residential and commercialproperties, or agricultural land;

Injuries or deaths to people .

4.2 Methodologies for assessment related to structuraland non-structural elements at risk

4.2.1 Assessment for structural elements - economic damageto properties


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Figure 4.1 Generic floodwater depth versus economic damage curve usedto assess economic damage to a property

It should be noted that considerable amounts of data are required toestimate economic damage to residential and commercial properties.


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PeopleThe number of people injured or killed during a flood is another method by

which the flood risk can be assessed. A recent research project in the UKfound that the number of people injured within a given zone that is at riskof flooding can be expressed as follows:

Ninj = function (Nz, FHR, AV, PV)

Where:Ninj is the number of people;Nz is the number of people in the flood hazard zone at ground or basementlevel;FHR is the flood hazard rating. This is a function of floodwater depth,velocity and debris;AV is the area vulnerability. This is a function of the effectiveness of floodwarning, the speed of onset of flooding and the nature of the area (forexample the type of buildings)PV is the people vulnerability. This is a function of the age and health of thepeople living in a particular flood hazard zone.

The number of fatalities caused a flood, Nfat, can be expressed as a follows:

Nfat = function (Ninj, FHR)

Hence to assess the flood risk to people the following has to be assessed:


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on the scale at which the analysis is carried out. The flood hazard, withrespect to people, is categorised as follows:

Low caution; Moderate dangerous for some people (for example the elderly and

children); Significant dangerous for most people; Extreme dangerous for all people.

Area vulnerability The vulnerability of a particular area to floods, with respect to people maybe expressed as follows:

AV = function (SO, NA, FW)

Where:

AV is the Area Vulnerability;SO is the Speed of Onset of the flood. This may vary from a few minutes toseveral hours;NA is the Nature of the Area. For example areas with mainly multi-storeyapartments would be classed as low risk areas, whereas areas comprisingparks or mobile homes would be classed as high risk;FW is the Flood Warning and is a function of the coverage, warning timeand action taken.


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(iii) A typical probability versus economic damage curve used toassess annualised average damage is shown in Figure 4.2. A

number of considerations are critical to the accuracy of thecalculation of annualised average damage. These are:

It is vital that the threshold of flooding is correctly defined. This is as thereturn period at which flood damage just begins;

It is important that the probability versus economic damage curve isdescribed by a number of points exceeding four, so that errors of interpolation are not excessive.

In general it has been found that economic damage needs to be estimatedfor the 1 in 5, 1 in 10, 1 in 25, 1 in 100 and 1 in 200 year return periodfloods to accurately estimate annualised average damage. It should benoted that where there is a high level of protection against flooding a higherreturn period flood (for example, a 1 in 1000 year return period).

When interpreting the flood risk in terms of annualised average damage(AAD), it should be noted that the AAD could be large in two contrastingsituations as follows:

When the consequence (i.e. economic damage) is large but theprobability of the flood event is low. This is when high economicdamage occurs from an event with a large return period i.e. manythousands of properties might be affected by a flood with a return periodof 1 in 1,000 years;


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PeopleThe annualised average deaths or injuries to people may be estimated in a

similar way to the annualised average damage.

4.2.4 Examples of vulnerability mapsFigures 4.3, 4.4 and 4.5 show typical examples of vulnerability mapsrelated to flooding.

Source: Reference 5


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Figure 4.5 Mapping showing social vulnerability and number of people


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In practice, however, exposure and vulnerability are often captured in theassessment of the consequences; thus risk can be viewed in simple terms

as:

Risk = Probability of flood event occurring x Consequences

5.2 Units of riskIn general, risk has units. However, the units of risk depend on how theprobability and consequence are defined. Flooding can have manyconsequences, some of which can be expressed in monetary terms.Consequences can include fatalities, injuries, damage to property or theenvironment. The issue of how some of the consequences of flooding can bevalued continues to be the subject of contemporary research. However,risk-based decision-making is greatly simplified if common units of consequence can be agreed upon. It is, therefore, often better to usesurrogate measures of consequence for which data are available .For example, number of properties may be a reasonable surrogate for thedegree of harm/significance of flooding and has the advantage of beingeasier to evaluate than, for example economic damage or social impact. Animportant part of the design of a risk assessment method is todecide on how the impacts are to be evaluated . Some descriptions of

consequence are:

Economic damage (national, community and individual; Number of people/properties affected;


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The dynamic nature of future flood risk is shown in Figure5.1.:

Source: Reference 1


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5.3.5 Changes in land useThe following changes in land use will change the level of flood risk:

Change in the number of properties and/or people living in thefloodplain;

An increase in the urbanisation of the catchment resulting in increasedrunoff.

When estimating changes in flood risk resulting from an increase (ordecrease) in urban area in an area should initially be based on developmentscenarios based on information from local, regional and national planningauthorities. These changes should be incorporated in any futurehydrological and hydraulic modelling to assess future hazard and also whenassessing the consequences of flooding (for example in terms of thenumber of people or properties affected). A typical example of the urbandevelopment scenarios that are often assessed at short and medium/longterm temporal scales are shown in Figure 5.2.


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5.4 Methodologies for risk analysis assessment

Risk analysis can be defined as a methodology to objectively determinerisk by analysing and combining probabilities and consequences . Flood riskassessment comprises understanding, evaluating and interpreting the

perceptions of risk and societal tolerances of risk to inform decisions and actions in the flood risk management process.

5.4.1 Qualitative and quantitative methodsRisk is generally assessed in terms of a qualitative or quantitative analysis.In terms of flood risk qualitative assessments tend to categorise flood riskto people or buildings (for example as high, medium or low). In terms of quantitative assessments flood risk in terms of damage to assets will bequantified typical in economic terms ( ) and for people it is in terms of thenumber of people injured or who have died.

5.4.2 Functions of risk analysisTo evaluate the flood risk, separate consideration needs to be made of thethree generic components:

The nature and probability of the hazard; The degree of exposure of people and assets to the hazard; The vulnerability of the people and/or assets to damage or harm should

the hazard occur.


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Flood risk assessments in terms of economic damageThe process used to assess flood risk in terms of economic damage is

summarised in Figure 5.5.

Assessment of flood risk in terms of economic damage at different spatial scalesMethod used to assess flood risk in terms of economic damage at differentspatial scales is summarised in Table 5.1. It should be noted that at eachscale a national property data set is required. This national property dataset would include for each residential and commercial property in thecountry the data defined in Section 4.2.1 of this report.

Table 5.1 Summary of assessing flood risk in terms of economic damageat a number of different spatial scales

Level of

assessment

Flood hazard Economic damage

National Flood extents anddepths based on anational DTM andflood levels

National property and agricultural data setstogether with generic water level versuseconomic damage curves. Threshold level of properties assumed to be the same as theDTM.

Regional orcatchment

Broad scale hydraulicmodelling of thecatchment

National property and agricultural data setstogether with generic water level versuseconomic damage curves.


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Table 5.2 Summary of assessing flood risk in terms of people at anumber of different spatial scales

Level of assessment

Flood hazard Area vulnerability People vulnerability

National Flood extents basedon a national DTMand design floodlevels

Based on nationalproperty data sets

Information based onnational census data

Regional orcatchment

Broad scalehydraulic modelling

Based on nationalproperty data setsaugmented byinformation from localgovernment

Information based onnational census dataaugmented byinformation from localgovernment

Local Detailed one or twodimensionalhydraulic modelcalibrated andverified against a

number of observedflood events

Based on nationalproperty data setsaugmented byinformation from localgovernment

Information based onnational census dataaugmented byinformation from localgovernment


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5.4.3 Examples of risk maps and legends

Examples of flood risk maps are shown below. Figure 5.7 show shows anational flood risk map for England and Wales showing how the flood risk interms of economic damage may change under different economicdevelopment scenarios by the year 2080. Figure 5.8 shows a flood risk topeople map in terms of the number of deaths that are likely to occur if a 1in 1000 year coastal flood event occurred.

2080sWorld markets

2080sGlobal

sustainability


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Source: Reference 5 Figure 5.7 Flood risk maps showing the percentage of deaths that may

occur under a 1 in 1000 year flood event in Kinmel, Wales


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Figure 5.8 A local flood risk map showing the economic damage for aflood that occurred in 1993 in Offenau in Neckar, Germany

Number of

casualties


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6 Risk management

6.1 Generic risk management optionsThere are several ways of managing and reducing the overall risk of flooding, which may be discussed in similar generic terms to the riskidentification process, broadly these are:

(i) Controlling the source;(ii) Controlling the pathway;

(iii)

Controlling the exposure;(iv) Controlling the vulnerability.

6.1.1 Controlling the sourceExamples of source control options include:

Use of infiltration systems to manage surface water runoff; Dredging and the cutting of the channel vegetation to maintain

channel capacity; Retention of natural flood storage on floodplains.

6.1.2 Controlling the pathway Examples of controlling the pathway are:

Construction of mitigation measures such as flood walls; Emergency operations to temporarily raise defence levels during a


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the risk, distinguishing between rare, catastrophic events and morefrequent less severe events. For example, risk methods adopted to support

the targeting and management of flood warning represent risk in terms of probability and consequence, but low probability/high consequence eventsare treated very differently to high probability/low consequence events.Other factors include how society or individuals perceive a risk (a perceptionthat is influenced by many factors including the availability and affordabilityof insurance or exposure to high flow velocities for example), anduncertainty in the assessment.

It is thus important when considering the significance of a risk thatreference is made not only to the numerical value of the probability timesconsequence, but also to how it will be perceived by society or theindividual.

A central question in risk management refers to the acceptance of risk bythe people and the decision-makers. From an engineering point of view ageneral framework for acceptability criteria has been developed that is

based on a three-tier system, shown in Figure 6.1. This involves thedefinition of the following elements:

An upper-bound on individual or societal risk levels, beyond which risksare deemed unacceptable;

A lower-bound on individual or societal risk levels, below which risks aredeemed not to warrant concern;

An intermediate region between (i) and (ii) above, where further


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Source: Reference 1

Figure 6.1 Acceptable risk levels and the ALARP principle


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7 Glossary of all keywords

Accuracy The closeness to reality.Annualised average damage This is the average economic damagefrom flooding that can be expected in any year.Catchment modelling A model that is represents the whole of thecatchmentCoastal floods A flood generated by a high tide or storm surge in thecoastal plainConsequence - An impact such as economic, social or environmentaldamage/improvement that may result from a flood. It may be expressedquantitatively (e.g. by. monetary value), by category (e.g. High, Medium,Low) or descriptively.Damage potential - A description of the value of social, economic andecological impacts (harm) thatwould be caused in the event of a flood.Deterministic process/method - A method or process that adoptsprecise, single-values for all variables and input values, giving a singlevalue outputDigital elevation model (DEM) - A database of elevation datarepresented by a regularly-spaced set of x,y,z locations.Digital terrain model (DTM) A digital representation of the height of the earths surface referenced to a particular datum.Exposure The qualification of the receptors that may be influenced by aflood hazard, for example, the number of people and their demographics,


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Pathway In the context of floods provides the connection between aparticular source (for example, marine storms) and a receptor (for example,

property) that may be harmed. For example, the pathway may consist of the flood defences and flood plain between a flow in the river channel (thesource) and a housing development (the receptor).Plains floods Floods that are usually generated from large catchmentsthat have been subjected to long periods of heavy rainfall. They arecharacterised by long periods of inundation and a relatively slow rise inwater level.Probabilistic method - A method in which the variability of input values

and the sensitivity of the results are taken into account to give results inthe form of a range of probabilities for different outcomes.Rainfall-runoff modelling A model used to estimate runoff from an areaunder various rainfall, land use and soil moisture conditionsRating curve The relationship between water level and flow for a givenriver cross-section.Receptor - Receptor refers to the entity that may be harmed (for examplea person, property, habitat etc.). For example, in the event of heavy rainfall

(the source) floodwater may propagate across the flood plain (the pathway)and inundate housing (the receptor) that may suffer material damage (theharm or consequence). The vulnerability of a receptor can be modified byincreasing its resilience to flooding.Resilience - The ability of a system/community/society/defence to react toand recover from the damaging effect of realised hazards.Return period - The expected (mean) time (usually in years) between theexceedence of a particular extreme threshold. Return period is traditionally


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Susceptibility The propensity of a particular receptor to experienceharm.

System - In the broadest terms, a system may be described as the socialand physical domain within which risks arise and are managed.Threshold level The threshold level, in the context of a property, is thelevel above which the property will be inundated by floodwater.Two dimensional hydrodynamic model A hydrodynamic model thatprovides results in two dimensions.Vulnerability - Characteristic of a system that describes its potential to beharmed. This can be considered as a combination of susceptibility and

value.


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8 References

1. FLOODSite (2005) Language risk project definitions, Version 4.0,Report T32-04-01, EC project on Integrated Flood Risk Analysis andManagement Methodologies

2. Env i ronmen t Agency, Eng l and and Wa le s webs i t ehttp://www.environment-agency.gov.uk/

3. Danish Hydraulics Institute (DHI)4. Department of the Environment Food and Rural Affairs

(Defra)/Environment Agency, UK (2004) Modelling and decisionsupport framework version 3.0

5. Department of the Environment Food and Rural Affairs(Defra)/Environment Agency, UK (2005) Flood risk to people project

6. Department of the Environment Food and Rural Affairs(Defra)/Environment Agency, UK (2004) Risk Assessment of floodand coastal defence for Strategic Planning (RASP) project

7. Delft Hydraulics, The Netherlands8. HR Wallingford Ltd, UK9. UK Government Department of Science and Technology (2002)

Foresight: Future flooding


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Appendix:

Operational standards for risk assessment aimedat spatial planning

1. Simplified model for flood hazard mapping aimed ata legal directive

One of the simplest ways in which flood hazards can be displayed is interms of the spatial extent of the flooding. The spatial extent of the floodshould be assigned to a specific return period or annual probability. Ingeneral the most commonly used return period is 1 in 100 years, i.e. theflood that has an annual probability of 1% of occurring. Other commonlymapped return periods include: 1 in 100 years, 1 in 200 years, 1 in 50years, 1 in 20 years, 1 in 10 years and 1 in 5 years. An example of a floodextent map is showing the flood extents without flood defences in place isshown in Figure A1.


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Figure A2 Local scale flood depth map


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gauging stations. If significant areas of the country are unguaged then asimple method is needed to estimate flood flows. This is often based on

a simple empirical model (e.g. where flood flows are correlated againstcatchment area, rainfall etc) Production of relationships between flood flows and flood levels .

This is often done by using a simple equation such as the Manningsequation that relates flow to water level.

Production of the flood extent and depth . A GeographicalInformation System (GIS) is used to produce a flood extent and depthgrid. A water surface needs to be generated. This is done by

triangulating the water levels to form a triangular irregular network(TIN) representing the water surface. The flood extent is calculated fromthe point at which the water surface intersects the DTM. A water depthgrid can be created by converting the water surface TIN to a watersurface grid. The DTM grid is then subtracted from the water surfacegrid to give average depths in each grid square.

Catchment scale flood extent and depth maps

To produce a catchment scale flood extent and depth map the following aredata required:

A digital terrain model (DTM) that covers the entire catchment; A broad scale hydraulic model of the catchment; Production of. the flood extent and depth. This has been described

above.


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2.1. Multi-risk assessment perspective as element of theStrategic Environmental Assessment

The EU Directive on Strategic Environmental Assessment (SEA) that interms of natural hazards the following risk-related aspects should beconsidered:

The probability, duration and frequency of the event; The risks posed to human health or the environment; The magnitude and the spatial extent of the hazard; The value and vulnerability of the area.

In terms of the relationship between natural hazards and SEAs it wouldappear that both the risks to properties and to people need to be assessed.

2.2. Methodologies, functions and outputs

The most common methodologies and their associated functions andoutputs for the assessment of risk to properties and to people have beendescribed in Chapters 4 and 5 of this report . Figures A3 and A4 showschematic diagrams of the methods for assessing the flood risk in terms of economic damage to properties and injuries/deaths to people respectively.


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B.II Seismic risk

Authors: Silvia Cozzi, Floriana Pergalani, Vincenzo Petrini,POLIMI

1 Physical definition of Seismic Risk .......................... 3

1.1 Typologies.................................................................... 3

1.2 Intensities, Severity, Magnitude ...................................... 3

2 Hazard assessment ................................................ 4

2.1 Definition ..................................................................... 4

2.2 Current methodologies for analysis and data availability..... 5

2.3 Problem of scale............................................................ 6

2.3.1 Temporal scale ..................................................................... 62.3.2 Scale of analysis and representation ....................................... 6

3 Elements at risk, exposure and analysis of


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4 Analysis of risk..................................................... 14

4.1 Definition of risk.......................................................... 144.2 Levels of investigation ................................................. 14

4.3 Methodologies for risk assessment for different levelsof study ..................................................................... 15

4.3.1 First level studies: territorial exposure .................................. 16

4.3.2 Second level studies: damage scenario ................................. 17 4.3.2.1 Basic Seismic hazard..............................................................174.3.2.2 Physical vulnerability..............................................................264.3.2.3 Damage scenario evaluation....................................................29

4.3.3 Third level studies: seismic risk............................................ 314.3.3.1 Local seismic hazard assessment .............................................31

4.3.3.1.1 Methodologies for evaluating site effects ...........................314.3.3.1.2 Instability evaluation......................................................32

4.3.3.1.3 Scale of analysis and representation.................................324.3.3.2 Physical vulnerability assessment.............................................37

4.3.4 Laboratorial experiments ..................................................... 42

5 Risk management................................................. 42

5.1 Perception .................................................................. 42


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1 Physical definition of Seismic Risk

1.1 Typologies

Earthquakes are the most evident expression of crustal breaking occurringat a variable depth ranging from a few to some hundreds kilometres.According to this hypothesis, crustal rocks are subject to deformationbecause of movements of the ground that make them accumulate energy.

When in some points this level of deformation overcomes the resistance of the material, there occurs a breaking occurs that quickly propagates acrossa surface, called fault plane; the extension of the rupture depends on thecharacteristics of the materials and on the level of deformation of the area:the bigger the broken area is, the stronger the earthquake will be. After thebreaking, part of the energy is given back in terms of elastic waves thatpropagate in all directions.The most evident aspect of the seismic event is therefore the rapid and

sometimes violent soil motion.

1.2 Intensities, Severity, Magnitude

The earthquakes destructive power can be described in several waysdepending on the information available at each singular event.

Data available for the study of earthquakes can be collected under three


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with terrestrial surface. The difference in arrival times of the waves isthe basic element for the location of the earthquake source.

c. Accelerometric registrations . The third and last method to evaluateearthquakes is through soil motion registration obtained hanks oaccelerograms, instruments capable of supplying registrations inproportion to earthquake accelerations. The simplest parameter that canbe used for this measure is the amount of the maximum recordedacceleration.

The magnitude is, instead, a value that represents the level of energy

released by the singular considered event. This value is recorded in the Historical recorded events catalogue that associate the magnitude valuewith the singular earthquake took into consideration.


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because an exact prevision cant be given for the time being. Statisticanalysis of the past events that occurred in a specific site must be done inorder to obtain a right value of the hazard), or considering an individualevent (in this case a deterministic approach is followed).

A variety of methods can be classified according to different initialhypotheses, objectives and detail levels. They are divided into:

A. Probabilistic approach: they permit to obtain foresights about futureevents in a specific site, in particular they consent to define the probabilityof having an event stronger than an established severity in a given timeperiod, thanks to probabilistic analysis of past events. The result is adistribution function in the site and the determination of possible hazardindicators.

A.1. Source zone method. It is one of the most used methods for hazardassessment. It is based on two hypotheses:

- uniform spatial distribution of the events in seismogenetic;- Poissonian distribution of occurrence periods.

A.2. Renewal process. This method modifies the basic hypothesis of thepreceding approach, abandoning the hypotheses of stationarity and theone about the uniform spatial distribution to calculate the time-windowbetween subsequent events.

B. Deterministic approach: damage scenario. They consider a singularevent and its propagation in surrounding areas (scenario), this will permit tostudy site effects (damage scenario).


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- Magnitude attenuation. These models use as severity indicator themagnitude value.

The above data are applied to investigate how a phenomena propagates farfrom the epicentre and, consequently, they can be used to investigate thevariation of severity parameters of intensity attenuation or of magnitudeattenuation.

2.3 Problem of scale

2.3.1 Temporal scale

The time scale can be taken into consideration with respect to the as far asthe hazard and to the vulnerability.

When a probabilistic hazard is estimated, it is possible to foresee somerecurrence periods by assigning (at regular time intervals), a Pick Ground

Acceleration (P.G.A.) in given time intervals and in a specific site. Obviouslythe P.G.A. value will be more or less serious according to the consideredtime-window: i.e., it can be considered more serious as far as a 1000-year-recurrence period rather than a 500-years one.

2.3.2 Scale of analysis and representation

In order to study the hazard component it is possible to map the territory


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3.2 Current methodologies for assessment, typology of elements at risk and most common damagepotentials

3.2.1 Analysis of vulnerability for building

Referring to buildings, seismic vulnerability is the behavioural characteristicdescribed by a cause-effect law, where the earthquake is the cause and the

damage is the effect.Seism and damage measures are the most widely used parameters,macroseismic intensity or soil maximum acceleration are the ones used forterritorial dimension.

Existent techniques to supply data about vulnerability can be variouslydivided:

A. Based on the results produced:1. direct techniques : just in one step they supply an effective prevision of damages caused by earthquakes;

2. indirect techniques : they consist in two steps. The first a vulnerabilityindex V is produced; then a correlation between earthquakes anddamages depending on the index is established;

3. finally, the conventional techniques produce a vulnerability index that,unlike the direct ones, is not associated to a damage forecast, but is


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characterized by few main features (i. e. the type of vertical orhorizontal structures), for which a probability damage matrix is defined.

An example of vulnerability assessment, carried out according to thismethod, has been carried out using data resulting from about 36.000buildings in 41 municipalities damaged by the earthquake of the Irpiniain 1980 (Braga et al., 1982; 1984) for which the following procedure wasfollowed:1) Detailed survey carried out on the basis of a card containing data

about the structural typology and damage levels of each building;2) Damage level related to thirteen different structural typologies

singled out on the basis of the kind of vertical and horizontalstructure;

3) the above mentioned thirteen typologies have been successivelygrouped in three classes (A, B, C) to make them correspond to thevulnerability classification included in the macroseismic scale MSK-76(Medvedev, 1977);

4) Statistics elaboration of damages observed in recent earthquakes todefine the relationship between the severity of the event and thecharacteristics of the building;

5) Computing of the probability that a building belonging to a specifictypology class, undergoes a certain damage level when it is hit by anearthquake of a given intensity. This can be done by considering allthe buildings which have undergone the effects of the same damagelevel within municipalities that were affected by different intensitiesdegrees;

6) damage probability matrix obtained by repeating the operation for all


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1 data about the card (building identification key, municipality, card, team,date);

2 building location (aggregate, building, toponymy, town planning bonds);3 metric data (surfaces, landing hights, maximum and minimum out of

round highs);4 use (kinds of use, state, property, users);5 building age (typologies and classes of age);6 state of the trimmings;7 structural typology (vertical, horizontal, staircase, roofing);8 damage level and expance.

The second level allows to assess vulnerability by using representative dataabout buildings propensity to be damaged by a seismic event. In particularsome factors accounts for the behaviour of the elements, structural or not,some others of the behaviour of the whole building complex.1 sort and organization of resistant system;2 quality of the resistant system;3 conventional resistance;

4 position of the building and of the foundations;5 ceilings;6 planimetric configuration;7 elevation configuration;8 maximum distance between brickworks;9 roofing;10 non structural elements;11 general conditions/present state;


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For the Italian case, the assessment of vulnerability derives from thecombined use of two data-sets: ISTAT census data (that supply, for everysingle municipality, an esteem of the number and the volume of buildings)and the data collected in different occasions using vulnerability cards byG.N.D.T. (Gruppo Nazionale per la Difesa dai Terremoti).

In short, the building heritage is subdivided in:- two classes (brickwork and reinforced concrete) on the basis of the

structural typology;- six classes on the basis of the age of construction for the brickwork

buildings (1982) and four classes for reinforced concrete ones (1982);

- two classes (good and bad maintenance state) on the basis of theefficiency of technical systems;

- two classes (since two floors or more) on the basis of the number of floors.

Once that the building patrimony has been subdivided in classes, a

vulnerability description for every class must be developed. To do that samecriteria adopted to classify the national buildings inventory are followed,using the archives of second level vulnerability cards.

With the support of a table or using density probability curves derived bydata regression it is possible to assign a vulnerability index value to everyclass.

3 2 2 1 Scale of analysis and representation


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- evaluation of further factors that can increase or decrease, for everybridge, the vulnerability value compared with the one attributed on thebasis of the belonging class.

3.2.3.1 Scale of analysis and representation

For this kind of studies, aimed at the analysis of an individual object, it ispossible to refer to the town planning scale: 1:500 1: 5000.

3.2.4 Analysis of vulnerability for tunnels

This kind of evaluation concerns the already existent tunnels as well asthose not accessible by means of the related project report.

In this methodology the survey is based on detectable appearance on theoutside of the gallery and on measurements on the covering by usinggeotechnical instruments.

The survey card is made up of seven different parts concerning:- general information and characteristics (sections from 2 to 4);- conditions on the inside and appearance on the outside (Section 5);- covering characteristics and stress conditions (Section 6).

The survey is then articulated in three levels:

U1. General characteristics of the work:In the sections from 2 to 4 the card notes the following data.

Work geometry and parameters, such as:


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3.2.4.1 Evaluation of vulnerability index

To evaluate the vulnerability index, the conditions of the slope at theentrance and the exit, of the internal covering and hanged systems of thetunnel are taken into consideration.


For this kind of studies, aimed at the analysis of the singular object, it ispossible to refer to the town planning scale: 1:500 1: 5000.

3.2.5 Analysis of vulnerability for supporting works

This measurement deals with already existent supporting works as well asthe ones not accessible by means of the related project report. Therefore,many technical data are not available, that is: wall width, possible armatureplan, geotechnical characteristics of foundation soil and embankment.

Analysis is thus a first level analysis and it is based on parameters the canbe detected by means of either direct and surface measurements oroptically detectable aspects, which are recorded in the proper data form.

As technical objective data are missing, in the evaluation of the vulnerabilityindex the conditions of the building and of the surrounding environmentsmust be considered.

Main characteristics of the survey card data


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minimum scores foe each group of aspects and considering the best and theworst situations.


For this kind of studies, aimed at the analysis of the singular object, it ispossible to refer to the town planning scale: 1:500 1: 5000.

3.2.6 Analysis of vulnerability for network infrastructures

Network infrastructures (waterworks, sewage pipes, gas network, electricnetwork, streets and railways, etc) are complex structures composed bypipes, joints and plants, sometimes strongly, sometimes loosely linked oneto the other. So, it is important to study their vulnerability not only from aphysical point of view but also considering systemic and territorial aspects.The following methodology has been proposed in Italy to defineinterventions to reduce impacts that events like the seismic one canproduce.

Analysis and evaluation procedureThe method is composed by some analysis cards and evaluation matrixrelated to the networks in the different phases of emergency andrestoration. They contain the main parameters that can most influencevulnerability. The first step consists in compiling the analysis card of thesingular network and an assessment is carried out through a weighed sumof the vulnerability scores assigned to each component The results are


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In order to investigate the whole network system or just one singularnetwork on the territory, the scale to use is 1:5.000 1:50.000. Instead, if a particular network junction must be studied, it is better to refer to thetown planning scale: 1:500 1:5000.

4 Analysis of risk

4.1 Definition of risk

Combining the above-mentioned factors (hazard and vulnerability), it ispossible to assess the risk. This term defines the entity of damagesexpected in an area due to future events and it comes from the convolutionbetween the hazard and the risk components.

Damages expected can be the result of two different approaches to the riskassessment: the probabilistic or the deterministic one. Depending on theadopted methodology it is possible to achieve different results, useful toreach different aims.


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There are three different levels of investigation connected with three scalesof analysis and representation. For spatial planning, for example, they cango from general analysis to study the territory at macro scale to carry outexpeditious studies, in the first level, to an intermediate stage for thesecond level (regional scale), to a punctual level of study for the third level,where local aspects are investigated (local scale).

Those levels of study depend also on different objective fixed in advance.

If the intend of the study is the macro-priority research aimed to establish apriority of intervention on a territory, it can be enough to carry outprobabilistic analysis in the first level of investigation.

The second level of investigation can be useful to prearrange emergencyplans, having a look at the over-local scale. To arrange urban plan, instead,it is possible to implement both probabilistic analysis and scenarioevaluations at local scale for an in-depth level of investigation.

Objective of the

study

Type of analysisScale of

analysis andrepresentation

Level of

investigationGeneral analysis to study the

territory at macro scale to carryout expeditious studies

Nation scale First Level

Intermediate stage of investigation for over-local

analysisRegional scale Second Level

Spatial planning

Punctual level of study, wherelocal aspects are investigated Local scale Third Level


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The main directions that have been followed are:- experimental studies applied in one or more sites by well known

geological and seismological characteristics, both following a seismicevent, and for preventive purposes;

- laboratorial experiments and models to improve current availableengineering technologies;

- new monitoring systems implementation for large and little crustalmovements, increasing current available instrumentation by realizingnew software and past events registration systems.

Despite of the variety of pursued objectives, materials and methods used

and achieved results, the studies have been directed to reduce risk bycharacterizing and decreasing hazard or uncertainty elements, as well asprotection of more vulnerable territorial elements.

Depending on starting hypothesis assumed to define the hazard, there aremany different ways to assess risk that can be carried out on three differentinvestigation levels, from preliminary analysis to special investigations.

Working on territorial viewpoint, it means to lead studies reach tocharacterize:

- areas that need analysis of expected damages, meant to territorialseismic risk unit of measurement, for the first level of investigation;

- damage areas on the basis of different scenarios, in order to conductintermediate level analysis;

- punctual indications for special studies.


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Zone

Expected horizontalacceleration values with

probability of exceeding of

10% in 50 years(aB gB /g)

Horizontal acceleration values of anchoring of elastic responsespectrum (Technical Codes)

(aB gB /g)

1 > 0,25 0,35

2 0,15 0,25 0,25

3 0,05 0,15 0,15

4 < 0,05 0,05

Tab. 4.3.1 Identification of the basic criteria for identifying and classifying

seismic regions

What should be avoided is lack of homogeneity in border seismic areasbetween different regions. To this end, their identification must take intoaccount of a reference document at national scale. Starting from referencedocument, it is possible to estimate seismic zones lists formation and toupdate them.


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PROJECTWORKING

GROUP

INVESTI-GATED

AREAABSTRACT OBJECTIVES MATERIAL AND METHODS RESULTS

Geodynamicmodelling of anactive region of theMediterranean:the Apenninegeomodap

IstitutoNazionale diGeofisica,Roma, ItalyandGeoModApworking group

TheApennines

Multidisciplinary approach tomodel the recent geodynamicevolution of the Apennines,one of the most activeregions of the Mediterranean.

Definition of a geodynamic modelof the Apennines to serve as abasis for future multi-disciplinaryresearch and data collection andas a framework for immediateapplication in the assessment of seismic hazard, earthquakesurveillance, vulnerability of cultural heritage, protection of critical facilities, earthquakeprediction, land use planning,and deep fluids exploitation.

1) Definition of a geodynamic modelof the Apennines

2) Collection and processing of newGPS data in the area using existingvertices and installing new ones toincrease the coverage in the mostinteresting areas

3) Compilation of a new catalogue of seismic moments of large historicalearthquakes

4) Definition of soil structure in depthto improve digital data quality

5) Compilation of data-base withactual stress-data

6) Two and three-dimensionalanalogical models of theApennines/Tyrrhenian system

Data elaboration for determine the forceacting in the region between theAppennines and the Adriatic/Ionianplate

A basicEuropeanearthquakecatalogue and adatabase for theevaluation of long-termseismicity andseismic hazard(BEECD)

Istituto diRicerca sulRischioSismico, CNR,Milano, Italy

Europe Prepare a bas ic parametricearthquake catalogue of Europe and a database of primary data, with specialreference to long-termseismicity

1) To retrieve, evaluate andmake available, in a standardformat, the considerable bodyof data existing in publishedand unpublished studies

2) To investigate, according tostandard criteria, the mainearthquake for which noprimary data is available

3) To use this material forpreparing, according torigorous and transparentprocedures a basic parametricearthquake catalogue of Europe, to serve both as a toolfor understanding the long-term seismicity and as areliable input for seismichazard evaluation

1) Compilation of the working file

2) Evaluating the supporting data sets

3) Retrieving and improving thesupporting data sets

4) Compilation of a comprehensiveprimary dataset

5) Earthquake parametersdetermination

1) To develop a procedure which can be

adopted for future i mplementation2) Providing a good set of data and of

establishing priorities for futureinvestigation

At this stage it can be predicted that theearthquakes included in the WF will bedivided into three categories:

A. Selected earthquakes for whichcomplete, good quality studies will beretrieved or produced, includingintensity data points (8-10 %)

B. Earthquakes for which the availabledata will be retrieved and evaluated,without special improvement (20-30 %)

C. Other earthquakes, for which at leastroot evaluation will be performed (60-70 %).


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ABSTRACT OBJECTIVES MATERIAL AND METHODS RESULTS

Earthquakesprediction intectonic activeareas usingspace techniques

UniversitaFederico II diNapoli,Napoli, Italy

UniversittStuttgart,Stuttgart,Germany

DepartementGeophysiqueet Imageriegeologique,BRGM,Marseille,France

Campano-MoliseApennines

Study of the geodynamicsprocesses which haveaffected the chain of Matese,and on medium-short termthrough the study of thehistorical and actualseismicity and of grounddeformations which precedeand accompany earthquakes

Earthquake prediction on theMatese by:

1) monitoring of the grounddeformation and the seismicity

2) seismotectonic modelling of the area using historicalseismicity, tectonic andgeodynamical modelling of thearea

1) Historical and current seismicity2) Monitoring3) geological analysis4) Analysis of the deformation of

Appennine-Tyrrhenian System andgeodynamical model

5) Hypothesis for a seismotectonicmodel

In such conditions adequate results forearthquakes prediction could beachieved through the following way:1) Realization of the geodynamical

model of the regiontough which it ispossible to build the stress fieldcurrently acting

2) definition of hierarchy of seismogenetic areas through thegeodynamical and seismotectomcmodels

3) monitoring of the deformations of thesuspect areas

High resolutionimaging of 3-dstrain in seismicand volcanicregions usingdifferential SARinterferometry

Institut dePhysique duGlobe deParis, Paris,France IPGP

Institut furNavigation,Stuttgart,Germany INS

CentreNationald'EtudesSpatiales,Toulouse,France CNES

Politecnico diMilano, Milan,Italy - POLIMI

The use of multiple SARimages such as thosecurrently collected by thesatellites ERS-1 and Radarsatmakes it now possible todetect subtle changes in theEarth's land and ice surfaceover periods of days to yearswith an unprecedented scale(global), accuracy (cm level)and reliability (dayand night,all-weather). The techniqueinvolves interferometric phasecomparison of successive SARimages. SAR i nterferometrycan also generate highresolution topographic maps

1) The goal of this project is toassess the accuracy of thedifferential SAR interferometrytechnique to measure crustaldeformations in a realenvironment

2) Calibrating the differential SARinterferometry technique indifferent environments. Thiscalibration phase is the centralpart of the present study. Thecharacteristic signature,amplitude and spatialdistribution of each of theseeffects on SAR compleximages and SAR interferogrammust be investigated ondifferent sites representativeof different conditions anddifferent geophysicalprocesses, namelyearthquakes, volcanoes andlandslides.

Experiment in the following selectedsites:1) The Campi Flegrei and Vesuvius, in

Italy which provide a good exampleof critical interferometricconditions: small displacements,rugged topography, low coherence(urban area). Yet, this area is of major interest, given the riskinvolved for the population of Pozzuoli and Napoli.

2) The Etna volcano where a widerange of observations are availablefor a long period of time

3) The Saint-Etienne-de-Tinee areawhere a major landslide is movingat the impressive rate of Icm/day.This provides an example of largedisplacements with high spatialvariability over a very small area(of the order of 1km).

4) The Antarctic which provides anexample of SAR interferometryapplied to the ice-shelf

In this study, SAR interferometry hasdemonstrated its capability to producelarge scale digital elevation models or todetect small displacements of variousorigins, such as surface deformationproduced by a volcano, a landslide or Amoving ice-shelf. Other studies detectedthe effect of earthquakes, tides onglaciers, or phase surface changes. Thiscapability provides several fields of application with revolutionary toolswhich chance the accuracy of the studyregardless of the accessibility or groundinstrumentation.


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*Genesis andimpact of tsunamis on theEuropean coast -GITEC - anEuropean effortto foster tsunamiresearch

Dipartimentodi Fisica,Settore diGeofisica,University of Bologna,Bologna, Italy

Europeanareas

The project is structured infour main areas of researchand activity embracing: 1-tsunami generation, 2-tsunami potential, 3- tsunamipropagation 4 - tsunamiwarning and risk mitigation

Illustrate the main resultsattained by the project GITECand the basic methods used inorder to achieve them

1) European tsunami catalogue2) Study and simulation of

earthquake-induced tsunami cases3) Study and simulation of landsides-

induced tsunami cases4) Assembling of bathymetric data5) Recognition of tsunami deposits

through geological methods6) Tsunami warning system7) Epilot land management study

Tsunamis are produced by submarineand coastal earthquakes, by submarinelandslides and by volcanic eruptions.Though it is clear that the generationprocess must involve a suddendisplacement of a large volume of oceanwater, it is presently recognized thatthere are still many aspects of thisprocess that are uncertain and deserveinvestigation, which makes tsunamigeneration one of the key problems of tsunami research.

*Southern Europenetwork foranalysis of seismic data

IstitutoNazionale diGeofisica,Roma, Italia

IstitutoGeograficoNacional,Madrid

NationalObservatoryof Athens, Atene

Finsiel s.p.a.,Roma

In this paper we present theresults of the Project"Southern Europe Network forAnalysis Seismic Data"sponsored by the EuropeanCommunity. The project isstructured in four themes of seismological interestdeveloped by threeNational Institutes (Greece,

Italy and Spain) working ingeophysical fields, andsupported by high technologycompanies as Digital, Finsieland Telecom.

1) A telematic system for seismicdata exchange by means of aprivate satellite network wascreated and a standardprotocol for seismic dataexchange between the threeseismic national networksconnected by the satellitenetworks was realized

2) recovery of old waveformsrecordings of the mainearthquakes occurred at thebeginning of this century.

3) 3D Tomography and aninternational Workshop wasorganized in the frame of theSouthern Europe Network forAnalysis of Seismic Dataproject

1) 3-D model of seismic wave velocity of the mediterranean area2) data-bank connection to the MEDNETnetwork3) digitization of historical seismograms


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*Rapidtransfrontierseismic dataexchangenetwork:Transfrontiergroup

TransfrontierGroup

Understanding the sourcesand reasons for our seismicityand the hazards we areexposed to dependsfundamentally on good dataand, for Europe, which isdivided politically into smallregions in relation to itstectonics, it is essential thatgood data exchange isachieved

1) Establish the definition of "significant earthquake";

2) Install a computer bollettinboard at each partecipant'slaboratory which will showdata acquired during theprevious three monthstogether with an 'earthquakealert' area containinginformation on immediatesignificant earthquakes;

3) Develop or adopt standarddata exchange formats to beused for computer-to-computer transfer of waveformdata;

4) Implement waveformexchange between participantsfor significant earthquakes;

5) Transmit data continuouslyacross selected borders wherethis proves to beadministratively possible;

6) Upgrade the seismicmonitoring network in Portugaland add key monitoringstations in border regions of other participants whereappropriate.

Establishment of a network of institutions with national or quasi-nationalresponsibilities for earthquake monitoring

The adoption and gradual implementation of the e-mail based softwaredeveloped at ETH, Zunch (Auto Data Request Manager, ADRM) is speeding updata transfer and is placing participants on a convergent path with other relatedactivities in Europe and more widely.

New seismc stations have been installed to improve border region coverage anda

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