Tsunami Hazards in Cascadia :                  by           Timothy J. Walsh   Washington Department of Natural           ...
•On April 1, 1946, amagnitude 8.0 (Mw)earthquake with thesource in theAleutian Islands tothe south of UnimakIsland generat...
•Only thefoundation andpart of theconcrete sea wallremained. All fiveoccupants werekilled. The wavesdeposited debrisas hig...
The school children noted that the water had receded
•Many went down to the shore to watch
Across what hadbeen the playingfields is themonument to thevictims
•At least 24 people were killed here, many of whom were childrenplaying by the waterfront. The tragedy of the 1946 tsunami...
Abridged fromSeismicity of theUnited States,1568-1989(Revised), byCarl W. Stoverand Jerry L.Coffman, U.S.GeologicalSurveyP...
Valdez sits on the edge of an outwash delta 150 km from the epicenter. Duringthe shaking, the unstable, saturated material...
Tsunami damage from the      Highway 109 bridge over   1964 Alaska earthquake           Copalis River                     ...
This earthquake also generated a Pacific Ocean-wide tsunami that killed 110people, 8 here in Crescent City, CA. Note fire ...
1993OkushiriIslandA view of tsunami and related fire damage on southeast OkushiriIsland in the community of Aonae. Photo o...
On the west side of Okushiri Island many locations experienced a maximum runup ofover 20 m. This small valley leading to t...
Placer                                                     River Silt                                                     ...
Right, subsided marshalong the Niawiakum River,                             Tsunami sandssouthwest Washington.Below, note ...
The realization that Cascadia was active was instrumental to the creation ofthe National Tsunami Hazard Mitigation Program...
The modelcalculatesthe watersurfaceelevationand velocityat each gridpoint
Tsunami parade at Hiro.                                                Storm surge trace                            REMEMB...
A TRAGEDY OF FOREIGN TOURIST WHO COULD NOT UNDERSTAND WARNING                Her last position                  from Nobuo...
Washington has a limited historical record, so we rely onmodeling to establish tsunami hazard zones
A tsunami generated by a Cascadiasubduction zone earthquake willarrive in less than 45 minutes. Forthese events, as was th...
After  TWO BUILDINGS    IN AONAE,       1993                  DuringBefore            (北海道新聞社)                    from Nob...
THE TWO     BUILDINGS   THAT REMAINED.                                           Tsunami traceThis building stopped a hous...
Those two buildingsand other Japanesetsunami defensestructures formedthe basis of a studyof buildings thatsurviveddevastat...
DEFENCE     STRUCTURESSEA WALLSTSUNAMI BREAKWATERSTSUNAMI GATEHIGHTENING OF RIVER DIKES               from Nobuo Shuto
ARTIFICIALLY-ELEVATED GROUND                      from Nobuo Shuto
SEA-WALLS  WORKEDThe 1968 tsunami reflected bysea-walls.                from Nobuo Shuto
from Nobuo Shuto     SEA-WALLS   DID NOT WORK.The 1993 tsunami was higher thanthe sea-walls by 5 m.
from Nobuo ShutoSHELTER TOWER  4th & 5th: Shelter  3rd: Tsunami museum  2nd: Meeting room  1st: Ware house          Tsunam...
Expected                                        tsunami                                        Past tsunamiAN ELEVATED SHE...
© 2010      Extent of debrisGerman                                                           Tagajo CastleAerospaceCenter(...
At Minami-Sanriku town,an apartmentbuilding wassituated rightnext to thecoast anddesignated asan evacuationbuilding asshow...
This three-storybuilding (below) wasthe disastermanagement centerof the town whichwas also designedto function as atsunami...
We formed a partnershipwith FEMA and theApplied TechnologyCouncil to providebuilding code styleguidance for buildingfacili...
Project Safe Haven:     Tsunami Vertical       EvacuationLong Beach Peninsula/Pacific County
Safe Haven Options (from FEMA 646):Towers –• Limited Space• Blocks Views• Few Options for ShelterBuildings –• Expensive   ...
Vertical Evacuation Safe    Haven Project • Community-based,   ‘bottom-up’ approach • All options (buildings,  towers, ber...
Safe Haven Berms
Safe Haven Berms
Safe Haven Towers
Safe Haven Buildings
Civilization exists bygeological consent—subject to change withoutnoticeWill Durant
National Tsunami Hazard      Mitigation Program      nthmp.tsunami.gov      Division of Geology dnr.wa.gov/ResearchScience...
Tsunami Hazards in Cascadia
Tsunami Hazards in Cascadia
Tsunami Hazards in Cascadia
Tsunami Hazards in Cascadia
Tsunami Hazards in Cascadia
Tsunami Hazards in Cascadia
Tsunami Hazards in Cascadia
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Tsunami Hazards in Cascadia

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Speaker: Timothy Walsh, Washington Department of Natural Resources Division of Geology and Earth Resources.

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Transcript of "Tsunami Hazards in Cascadia"

  1. 1. Tsunami Hazards in Cascadia : by Timothy J. Walsh Washington Department of Natural ResourcesDivision of Geology and Earth Resources Partners in Emergency Preparedness April 27, 2011
  2. 2. •On April 1, 1946, amagnitude 8.0 (Mw)earthquake with thesource in theAleutian Islands tothe south of UnimakIsland generated atsunami thatdestroyed this five-story lighthouse,located 9.8 m abovesea level.
  3. 3. •Only thefoundation andpart of theconcrete sea wallremained. All fiveoccupants werekilled. The wavesdeposited debrisas high as 35 mabove the sea.Although littledamage occurredin Alaska, exceptat Scotch Cap, thetsunami was oneof the mostdestructive ever tooccur in theHawaiian Islands.Photo credit: U.S.
  4. 4. The school children noted that the water had receded
  5. 5. •Many went down to the shore to watch
  6. 6. Across what hadbeen the playingfields is themonument to thevictims
  7. 7. •At least 24 people were killed here, many of whom were childrenplaying by the waterfront. The tragedy of the 1946 tsunamiprompted the U.S. Coast and Geodetic Survey to establish theTsunami Warning System
  8. 8. Abridged fromSeismicity of theUnited States,1568-1989(Revised), byCarl W. Stoverand Jerry L.Coffman, U.S.GeologicalSurveyProfessionalPaper 1527,United StatesGovernmentPrinting Office,Washington:1993. Prince William Sound, Alaska 1964 March 28 03:36:14 UTC (March 27 local) Magnitude 9.2
  9. 9. Valdez sits on the edge of an outwash delta 150 km from the epicenter. Duringthe shaking, the unstable, saturated material failed. A slice of the delta, 1,220m long and 183 m wide, slid into the sea, carrying the docks and part of thetown with it. The slide generated a wave which slammed the waterfront 2 to 3minutes after the onset of the quake. The wave demolished the rest of thewaterfront, destroyed the fishing fleet, and reached 2 blocks into town, killing 30people
  10. 10. Tsunami damage from the Highway 109 bridge over 1964 Alaska earthquake Copalis River The wave here was about 10-12 feet. Highway 109 bridgeHouse torn apart over Joe Creekat Pacific Beach
  11. 11. This earthquake also generated a Pacific Ocean-wide tsunami that killed 110people, 8 here in Crescent City, CA. Note fire in background. This event led tothe opening of a second tsunami warning center in Palmer, Alaska.
  12. 12. 1993OkushiriIslandA view of tsunami and related fire damage on southeast OkushiriIsland in the community of Aonae. Photo orientation is lookingnortheast. Numerous fires broke out following the tsunami, addingto the property loss and misery. More than 120 people were killedin Japan (Okushiri and Hokkaido Islands) by the tsunami.
  13. 13. On the west side of Okushiri Island many locations experienced a maximum runup ofover 20 m. This small valley leading to the ocean experienced a spectacular runup of 31m. Note the debris in the foreground, including a broken steel reinforced concrete utilitypole. Discolored and dead plants and grasses are evident on the hillside. This well-studied earthquake and tsunami led to significant advances in modeling tsunamis.
  14. 14. Placer River Silt Earthquake-induced ground crackDrowned forest in Girdwood, Alaska, killed in 1964 A.D. 1700 Ground surface 1,100 year old ground surface from Brian AtwaterDrowned forest along the Copalis River,Washington, killed in A.D. 1700
  15. 15. Right, subsided marshalong the Niawiakum River, Tsunami sandssouthwest Washington.Below, note pitfalls ofworking in tidal marshes. A.D. 1700 ground surface
  16. 16. The realization that Cascadia was active was instrumental to the creation ofthe National Tsunami Hazard Mitigation Program, which develops tsunamiinundation maps for vulnerable coastlines. These are based on a combinationof numerical modeling, and , where possible, paleoseismology.
  17. 17. The modelcalculatesthe watersurfaceelevationand velocityat each gridpoint
  18. 18. Tsunami parade at Hiro. Storm surge trace REMEMBER THE PASTTsunami monument from Nobuo Shuto
  19. 19. A TRAGEDY OF FOREIGN TOURIST WHO COULD NOT UNDERSTAND WARNING Her last position from Nobuo Shuto
  20. 20. Washington has a limited historical record, so we rely onmodeling to establish tsunami hazard zones
  21. 21. A tsunami generated by a Cascadiasubduction zone earthquake willarrive in less than 45 minutes. Forthese events, as was the case inBanda Aceh, the earthquake must bethe warning. Citizens must knowwhere to evacuate from and where toevacuate to, and must do so quicklyand on foot.Note the long peninsulas or spits oflow-lying ground. Ocean Shorespeninsula is 7 miles long and LongBeach peninsula is 20 miles long withlittle or no high ground over thosedistances. For these areas, tsunamidefenses are appropriate.
  22. 22. After TWO BUILDINGS IN AONAE, 1993 DuringBefore (北海道新聞社) from Nobuo Shuto
  23. 23. THE TWO BUILDINGS THAT REMAINED. Tsunami traceThis building stopped a house and boats.
  24. 24. Those two buildingsand other Japanesetsunami defensestructures formedthe basis of a studyof buildings thatsurviveddevastatingtsunamis wheneverything else inthe area wasdestroyed.
  25. 25. DEFENCE STRUCTURESSEA WALLSTSUNAMI BREAKWATERSTSUNAMI GATEHIGHTENING OF RIVER DIKES from Nobuo Shuto
  26. 26. ARTIFICIALLY-ELEVATED GROUND from Nobuo Shuto
  27. 27. SEA-WALLS WORKEDThe 1968 tsunami reflected bysea-walls. from Nobuo Shuto
  28. 28. from Nobuo Shuto SEA-WALLS DID NOT WORK.The 1993 tsunami was higher thanthe sea-walls by 5 m.
  29. 29. from Nobuo ShutoSHELTER TOWER 4th & 5th: Shelter 3rd: Tsunami museum 2nd: Meeting room 1st: Ware house Tsunami level Wat Ban Nyan, Khao Lak
  30. 30. Expected tsunami Past tsunamiAN ELEVATED SHELTER AT SHIRAHAMA SEA-BATHING RESORT, TOKUSHIMA PREF. from Nobuo Shuto
  31. 31. © 2010 Extent of debrisGerman Tagajo CastleAerospaceCenter(DLR). Tsunami Catalogue for the Sanriku District near the Sendai Area, mostly based upon Miyagi Showa Shinsho-Shi (Record of the Showa Earthquake and Tsunami in Miyagi Prefecture) and partially on Shuto’s memory In 869. Giant earthquake in the Tohoku District. Tsunami flooded up to the Tagajo castle near Sendai. Over 1,000 drowned.
  32. 32. At Minami-Sanriku town,an apartmentbuilding wassituated rightnext to thecoast anddesignated asan evacuationbuilding asshown byevacuationsigns, but therewere tracesthat tsunamialso hadreached the 4thfloor.
  33. 33. This three-storybuilding (below) wasthe disastermanagement centerof the town whichwas also designedto function as atsunami evacuationbuilding. At the timeof tsunami, aboutthirty municipalofficials evacuatedto the rooftop butonly ten of themsurvived. A youngfemale official whokept deliveringevacuation messageto the villagers untilthe last moment hasnot been found yet.
  34. 34. We formed a partnershipwith FEMA and theApplied TechnologyCouncil to providebuilding code styleguidance for buildingfacilities to withstand amagnitude 9 earthquakeand be suitable forvertical evacuation.Planning for the right sizeearthquake is critical.
  35. 35. Project Safe Haven: Tsunami Vertical EvacuationLong Beach Peninsula/Pacific County
  36. 36. Safe Haven Options (from FEMA 646):Towers –• Limited Space• Blocks Views• Few Options for ShelterBuildings –• Expensive • Better get it right the first time!• Very Large, Likely to Block Views• May require Private Development • Incentives for Height?Berms –• Least Expensive Option• Can be Multi-Purpose• May be Placed to Limit View Blocking
  37. 37. Vertical Evacuation Safe Haven Project • Community-based, ‘bottom-up’ approach • All options (buildings, towers, berms, etc.) are on the table for consideration Common Themes: • School Safety • Seniors and special needs populations • More conservative travel times
  38. 38. Safe Haven Berms
  39. 39. Safe Haven Berms
  40. 40. Safe Haven Towers
  41. 41. Safe Haven Buildings
  42. 42. Civilization exists bygeological consent—subject to change withoutnoticeWill Durant
  43. 43. National Tsunami Hazard Mitigation Program nthmp.tsunami.gov Division of Geology dnr.wa.gov/ResearchScience/ GeologyEarthSciencesEmergency Management Division emd.wa.gov

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