The Indonesian Earthquake and Tsunami Lessons for the United
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TheThe IndonesianIndonesian EarthquakeEarthquake andand TsunamiTsunami LessonsLessons forfor thethe UnitedUnited StatesStates Rupture zone of Rupture zone of 2004 Indonesian 1700 Cascadia Earthquake Earthquake 1000 km 1000 km Global distribution of earthquakes INDIAN OCEAN PACIFIC OCEAN INDIAN OCEAN ATLANTIC OCEAN NORTON MEDIA LIBRARY, 2001 M 9.3 December 26, 2004 earthquake Cascadia subduction zone Uplift Uplift Subsidence Breuh, 15 m water height VisualizingVisualizing inundationinundation Lhoknga, 20 m water height Jantang, 20 m water height VisualizingVisualizing inundationinundation Debris in tree branches Broken branches How high was the wave? 7 Lori’s + elevation above sea level = 47 feet high Lhokruet, Indonesia April 2005 Photo, Bruce Jaffe, USGS Banda Aceh, Indonesia Before Banda Aceh, Indonesia After Tsunami deposits 1964 1960 1700 Crescent Beach Motel, 1964 NorthNorth CoastCoast PlatePlate TectonicsTectonics Plan (map) View) Cross Section UniqueUnique GeologicGeologic SettingSetting The Cape Mendocino earthquakes were located close to the Mendocino triple junction where three plates, the Gorda, the Pacific and the North American, meet.. SubsidenceSubsidence GhostGhost ForestsForests Photo by Guy Gelfenbaum, USGS USG Photo Calang,Sumatra Copalis River, Washington Trees killed by coastal subsidence Trees killed by the 1700 in the 2004 Indonesian earthquake. Cascadia earthquake. SurfaceSurface DeformationDeformation -- UpliftUplift Nias Island, Indonesia Cape Mendocino, California Clam beds uplifted above high tide Dead and dying reef communities in the 2004 Indonesian earthquake killed by the 1992 Cape Mendocino Earthquake Lessons from Indonesia ComparingComparing thethe AcehAceh coastcoast andand SimueleuSimueleu IslandIsland JantangJantang LangiLangi Lessons from Indonesia JantangJantang Village,Village, SumatraSumatra •• Waves arrived 20 minutes after the earthquake •• Tsunami height 45 - 60 ft •• 100% structures destroyed •• 2% of population survived No one knew what to do… No previous awareness of tsunamis Current Activities: removing debris, gathering coconuts, reclaiming family land Lessons from Indonesia LangiLangi Village,Village,SimuelueSimuelue IslandIsland •• Waves arrived 8 minutes after the earthquake •• Tsunami height 30 to 45 feet •• 100% structures destroyed •• 100% of population survived Everyone knew to immediately go to high ground. Oral history of 1907 tsunami - Smong (Simuelue word for tsunami) New homes built on foundation slabs of destroyed structures Current Activities: building boats, gardening, fishing. Still dependent upon aid but normal village life has resumed. Above, the new cattle were provided by aid organizations. WhatWhat If?If? We don’t know what the next Cascadia earthquake and tsunami will do to the North Coast. We can make a reasonable guess based on paleo-seismic studies, modeling, and what has happened in other tsunamis. Freshwater Lagoon Scour cars and debris Before After ? Freshwater Lagoon: A tsunami could sweep over the sand spit, destroying Highway 101 and knocking cars and debris into the lagoon. The tsunami may be strong enough to scrape trees and vegetation off the hillside to a height of more than 30 feet. Base image used with the permission of the Coastal Records Project.