The Science Applications for Risk Reduction Tsunami Scenario. Perspectives on what can be done to become tsuanmi disaster resilient. Presentation courtesy of Dr Walter Hays, Global Alliance for Disaster Reduction
6. 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).
7. 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.
9. 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.
10. 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.
11. 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
16. 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.
17. TSUNAMIS
• OCCUR IN PACIFIC
“RING OF FIRE,”
INDIAN OCEAN,
CARIBBEAN, AND
MEDITERRANEAN
19. 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
20. PERSPECTIVES ON WHAT
CAN BE DONE TO BECOME
TSUANMI DISASTER
RESILIENT
Coastal planners are having meetings this
week around the state to digest the scenario
information and review their evacuation
plans.
21. 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 University
New Scientist MagazineNew Scientist Magazine
January 15, 2005January 15, 2005
23. 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 %
24. LOSS REDUCTION MEASURES
• PROTECTION
(BUILD INFRA-
STRUCTURE TO
WITHSTAND)
• LAND-USE
CONTROL
(COMMUNITY
PLANS)
Notas del editor
These images show how the vertical displacement of the ocean floor starts the generation of tsunami waves
There are several ways that a tsunami wave crest may appear to observers on the shore. The first is like a very quick rising of the tide. The second is a large cresting wave. The most often described appearance is called a bore. A bore appears like a wall of approaching water that is significantly higher than the existing water level. The image shows an example of a tidal bore in China. Although the bore shown is not a tsunami bore, it still demonstrates the appearance and characteristics of a bore that could be generated by a tsunami. Tsunamis generate a wave series that may continue for many hours. The first wave is rarely the largest in the series. Much damage can be caused by the outflow of water back to the ocean between waves. In some cases this reversed flow can cause more damage than the incoming waves.
Education is the most important factor in tsunami risk reduction. There are newspaper reports of a 10-year-old girl sending 100 people on one Thai beach to higher ground after seeing the sea recede, because she had been taught about tsunamis in school. The UN wants disaster reduction to be included in school curricula worldwide.
Victor was a former merchant seaman who had experienced a tsunami in Chile. When the water receded in his village, he ran around telling his neighbors to run for it. As a result, only one of several hundred inhabitants of his village was killed. Casualty rates in nearby villages were 70% to 90%.