ALASKA TSUNAMI SCENARIO

(Source: US Geological Survey)September 4, 2013

Walter Hays, Global Alliance for Disaster Reduction, Vienna,

Virginia, USA 

The Science Applications for Risk Reduction Tsunami Scenario

Stephanie Ross and Lucile Jones, Editors

The tsunami scenario team began work on the scenario before the

magnitude-9.0 earthquake/tsunami that struck Japan in March 2011

SCHEMATIC OF TSUNAMI WAVE (USGS)

SCENARIO CONCLUSIONS

• In the scenario, a tsunami generated by a massive earthquake off the coast of Alaska would leave the northern Orange County coast and Long Beach underwater.

• Source: U.S. Geological Survey report, Wednesday (Sept. 4, 2013).

SCENARIO CONCLUSIONS

• The simulated tsunami disaster follows a M9.1 earthquake in Alaska would force the evacuation of about 750,000 Californians and damage or sink one-third of the boats in California marinas.

COLLISION OF BOATS IN A MARINA (March, 2011)

SCENARIO CONCLUSIONS

• The twin ports of Los Angeles and Long Beach could be shuttered for at least two days because of strong currents, potentially losing $1.2 billion in business.

SCENARIO CONCLUSIONS

• The hypothetical simulated disaster would force the evacuation of about 750,000 Californians and damage or sink one-third of the boats in marinas statewide.

TIME TO GET OUT OF HARM’S WAY: Under the scenario, it would take about four hours for tsunami

waves to reach communities near the Oregon state line and about six hours

to reach San Diego

ESTIMATED ECONOMIC LOSSES: AT LEAST

$8 BILLION

BACKGROUND

BOOK OF

BOOK OF

KNOWLEDGE

KNOWLEDGE

- Perspectives

- Perspectives

On Science, Policy,

On Science, Policy,

And Change

And Change

REGIONAL DEFORMATION

EARTHQUAKE

TSUNAMI

VIBRATION

FAULT RUPTURE

FOUNDATION FAILURE

AMPLIFICATION

LIQUEFACTION

LANDSLIDE

AFTERSHOCKS

SEICHE

DAMAGE/LOSSDAMAGE/LOSS

DAMAGE/ LOSSDAMAGE/ LOSS

DAMAGE/ LOSSDAMAGE/ LOSS

DAMAGE/ LOSSDAMAGE/ LOSS

DAMAGE/ LOSSDAMAGE/ LOSS

DAMAGE/ LOSSDAMAGE/ LOSS

DAMAGE/ LOSSDAMAGE/ LOSS

DAMAGE/ LOSSDAMAGE/ LOSS

DAMAGE/ LOSSDAMAGE/ LOSS

DAMAGE/LOSSDAMAGE/LOSS

Basic Tsunami Mechanism

An earthquake causes a vertical movement of the seafloor, which displaces the sea water.

Large waves then radiate from the epicenter in all directions.

TSUNAMISTSUNAMIS

• OCCUR IN PACIFIC “RING OF FIRE,” INDIAN OCEAN, CARIBBEAN, AND MEDITERRANEAN

• OCCUR IN PACIFIC “RING OF FIRE,” INDIAN OCEAN, CARIBBEAN, AND MEDITERRANEAN

TSUNAMISTSUNAMIS

• GENERATE WAVES THAT CAN AFFECT DISTANT SHORELINES THOUSANDS OF MILES FROM THE SOURCE

• GENERATE WAVES THAT CAN AFFECT DISTANT SHORELINES THOUSANDS OF MILES FROM THE SOURCE

TSUNAMI WAVE APPEARANCE

• A tsunami wave crest has three general appearances from shore:– Fast-rising tide– Cresting wave– A step-like change in the

water level that advances rapidly (called a bore)

• Series of waves– Most tsunamis come in a series of waves that may last several hours– The outflow of water back to the sea between waves can

cause more damage than the incoming wave fronts– The first wave is rarely the largest

A bore on the Qian Tang Jiang River, China

Source: www.waveofdestruction.org

PERSPECTIVES ON WHAT CAN BE DONE TO BECOME

TSUNAMI DISASTER RESILIENT

PERSPECTIVES ON WHAT CAN BE DONE TO BECOME

TSUNAMI DISASTER RESILIENT

Coastal planners are having meetings this week around the state to digest the scenario information and review their evacuation plans.

Coastal planners are having meetings this week around the state to digest the scenario information and review their evacuation plans.

Tsunami Risk Reduction The least expensive and the most important mitigation effort is …

"Even without a warning system, even in places where they didn't feel the earthquake, if people had simply

understood that when you see the water go down, when you hear a rumble from the coast, you don't go down to investigate, you grab your babies and run for your life,

many lives would have been saved."

Lori Dengler, Humboldt State UniversityNew Scientist MagazineNew Scientist Magazine

January 15, 2005January 15, 2005

LOSS REDUCTION MEASURESLOSS REDUCTION MEASURES

• TSUNAMI WARNING/ SYSTEM

• DISASTER SCENARIOS

• EVACUATIONS

• TSUNAMI WARNING/ SYSTEM

• DISASTER SCENARIOS

• EVACUATIONS

The power of knowledge:

• Victor Desosa saved the village of Galbokka in Sri Lanka in 1994 because he knew what to do when the water receded.

• Only one inhabitant in his village was killed.

• Casualty rates in nearby villages were 70 – 90 %

LOSS REDUCTION MEASURESLOSS REDUCTION MEASURES

• PROTECTION (BUILD INFRA-STRUCTURE TO WITHSTAND)

• LAND-USE CONTROL (COMMUNITY PLANS)

• PROTECTION (BUILD INFRA-STRUCTURE TO WITHSTAND)

• LAND-USE CONTROL (COMMUNITY PLANS)