Talk by: Peter J. Haeussler pheuslr@usgs.gov 907-786-7447

Publish in

Documents

175 views

Please download to get full document.

View again

of 20
All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
Share
Description
The 1964 Great Alaska earthquake and tsunami: lessons learned in the 50 years since the dawn of plate tectonics. Talk by: Peter J. Haeussler [email protected] 907-786-7447. U.S. Department of the Interior U.S. Geological Survey, Anchorage, Alaska. 1964 earthquake damage in Anchorage, Alaska.
Transcript
The 1964 Great Alaska earthquake and tsunami: lessons learned in the 50 years since the dawn of plate tectonics Talk by: Peter J. Haeussler [email protected] 907-786-7447 U.S. Department of the Interior U.S. Geological Survey, Anchorage, Alaska 1964 earthquake damage in Anchorage, Alaska Active faults and significant earthquakes of Alaska learned in the 50 years since the dawn of plate tectonics
  • Earthquakes define the plate margins
  • ‘magmatic arcs’ are related to subduction zones
  • Alaska subduction zone cross section learned in the 50 years since the dawn of plate tectonics NW SE Plates of the world learned in the 50 years since the dawn of plate tectonics EQ energy release in the US 1960-2010 learned in the 50 years since the dawn of plate tectonics 99% in Alaska Mike West, Alaska Earthquake Center The 1964 Great Alaska Earthquake learned in the 50 years since the dawn of plate tectonics
  • March 27th, 1964, 5:36 PM. Good Friday
  • Magnitude 9.2
  • 2nd largest ever recorded
  • shaking lasted 4.5 minutes
  • Huge rupture area (~250x800 km)
  • Anchorage Uplift and Subsidence learned in the 50 years since the dawn of plate tectonics uplift Uplifted tidal flat Uplifted dock at high tide subsidence Village of Portage had to be abandoned ‘ghost forest’ Uplift and subsidence pattern is only consistent with a “ learned in the 50 years since the dawn of plate tectonicsmegathrust”
  • Max subsidence over large area of 2 m
  • Max uplift over large area of 4 m
  • Subsidence Uplift USGS Geologist Dr. George Plafker Tsunami Generation learned in the 50 years since the dawn of plate tectonics This mechanism of tsunami generation first recognized from USGS studies of the 1964 earthquake Tsunami Generation - landslide learned in the 50 years since the dawn of plate tectonics Locally generated tsunamis learned in the 50 years since the dawn of plate tectonics Alaskan deaths
  • 106 of 122 from tsunamis (87%)
  • 85 of the 106 from submarine landslide generated tsunamis (80%) Alaskan fjords are an ideal environment for producing submarine landslides
  • The scientific legacy of the 1964 event: the fingerprint of the worlds’ largest earthquakes
  • Occurred at a pivotal time earth science
  • Helped lead to acceptance of plate tectonics
  • Showed the worlds largest earthquakes are caused at convergent margins
  • Provided a mechanism for launching trans-oceanic tsunamis
  • All giant megathrust earthquakes are understood in the shadow of what was learned from 1964 (e.g. 2011 Japan, 2004 Indonesia, 1960 Great Chile, etc.)
  • 1964 earthquake gave birth to modern earthquake detectives the worlds’ largest earthquakes
  • Repeated pattern of uplift and subsidence with each megathrust earthquake allows us to determine the history of ancient earthquakes
  • Cascadia the worlds’ largest earthquakesmegathrust earthquake hazard
  • 1964 Alaska perspective allowed identification of coastal OR and WA earthquake hazard
  • Copalis River ghost forest at extreme high tide, December 1997 (Atwater and others, 2005). Geodesy: pre1964, today, and the future the worlds’ largest earthquakes today Pre-1964 ‘campaign’ GPS surveys today and the future conventional surveying New tools reveal earth deformation between and during earthquakes continuous GPS 2011 M9.0 Tohoku, Japan, earthquake the worlds’ largest earthquakes horizontal vertical From Grapenthin and Freymueller (2012) Motion during earthquake 2011 M9.0 Tohoku, Japan, earthquake the worlds’ largest earthquakes
  • Japan invested in seafloor geodesy
  • Data revealed huge offshore slip (~50+ m), which made a particularly big tsunami
  • We don’t know how unusual this was
  • Japan success: relative little shaking related building damage
  • TAPS Denali the worlds’ largest earthquakesfault crossing Before After
  • Success: Trans Alaska Pipeline withstood 5.4m (18ft) of fault offset during M7.9 quake
  • In the 50 years since 1964… the worlds’ largest earthquakes
  • We’ve made big gains in understanding earthquakes
  • We have success in reducing losses
  • We need to be vigilant
  • The most recent disaster fades from memory Just before the next one strikes - Ancient Japanese proverb
    Related Search
    We Need Your Support
    Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

    Thanks to everyone for your continued support.

    No, Thanks