Cascadia Great Earthquake and Tsunami Suite
I The Great Sumatran Earthquake and
Tsunami of December 2004
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II Is the stage being set for a Great
Cascadian Earthquake and Tsunami?
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III The Search for Great Cascadian
Earthquakes and Tsunamis in the Past
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IV Impact of a Great Cascadian Earthquake
and Tsunami on one Coastal Community
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V Rupture on the Seattle Fault: A Case
Study
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Natural Hazard Case Studies
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Unit I. The Great Sumatran Earthquake and Tsunami of December 2004
This unit is about the magnitude 9.3 earthquake that occurred on the shallow subduction zone east of Sumatra, Indonesia, in 2004 and the resulting devastating tsunami it generated. The Sumatran event provides a modern-day analog useful for framing other units in the Cascadia Suite concerning the potential for great earthquakes and tsunami in Cascadia; or it can stand alone as an investigation of processes leading to great subduction zone earthquakes.
The investigation begins with a regional view of the subduction zone boundary east of Sumatra in the Indian Ocean, the epicenter of the 2004 earthquake, and the extent of the rupture zone. Students begin to develop familiarity with the GIS tools by measuring the length of the rupture zone.
Students then gain an appreciation of the devastation brought by the tsunami that accompanied the earthquake by viewing amateur video footage of that terrible event. They view a NOAA animation of the tsunami as it swept across the Indian Ocean.
In the “What Happened?” section, students examine the convergent plate boundary and relative plate motions, along with seismicity data and the distribution of active volcanoes to understand the earthquake in the context of plate subduction. An animation gets across a fundamental concept of how a locked zone between subducting and overriding plates leads to buildup of stress with accompanying plate deformation, which when suddenly released generates the earthquake and tsunami with accompanying inversion of topography in the overriding plate. This concept will reappear in the companion Cascadia units many times. Students interpret the post-seismic horizontal deformation field in relation to the rupture zone using a precision GPS data set. They then interpret the post-seismic vertical deformation pattern along the plate boundary using satellite-based radiometric data on coral heads, and relate this to the conceptual model of co-seismic topographic inversion.
Comparison is made with the two other magnitude 9+ earthquakes that have occurred since modern recording has been available, the 1960 M9.6 earthquake on the subduction zone east of Chile—the greatest ever recorded—and the 1964 M9.2 earthquake on the subduction zone south of Alaska. Students compile information demonstrating that the three M9+ events have all characteristics in common: patterns of seismicity, active volcanic chains, long rupture zones, mega-tsunami generation, and the characteristic co-seismic inversion of topography leading to flooding of down-dropped coastal regions.
To aid understanding of concepts and generate interest, the unit makes full use of the GIS tools, animations, diagrams, historic photos, and a lyrical—if horrific—excerpt from a novel, the plot of which is based on the 1960 Chilean earthquake.
Download project files now...
ArcGIS version
MyWorld GIS version
This material is based upon work supported by the National Science Foundation under Grant Number DUE-0521936. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
This unit is about the magnitude 9.3 earthquake that occurred on the shallow subduction zone east of Sumatra, Indonesia, in 2004 and the resulting devastating tsunami it generated. The Sumatran event provides a modern-day analog useful for framing other units in the Cascadia Suite concerning the potential for great earthquakes and tsunami in Cascadia; or it can stand alone as an investigation of processes leading to great subduction zone earthquakes.
The investigation begins with a regional view of the subduction zone boundary east of Sumatra in the Indian Ocean, the epicenter of the 2004 earthquake, and the extent of the rupture zone. Students begin to develop familiarity with the GIS tools by measuring the length of the rupture zone.
Students then gain an appreciation of the devastation brought by the tsunami that accompanied the earthquake by viewing amateur video footage of that terrible event. They view a NOAA animation of the tsunami as it swept across the Indian Ocean.
In the “What Happened?” section, students examine the convergent plate boundary and relative plate motions, along with seismicity data and the distribution of active volcanoes to understand the earthquake in the context of plate subduction. An animation gets across a fundamental concept of how a locked zone between subducting and overriding plates leads to buildup of stress with accompanying plate deformation, which when suddenly released generates the earthquake and tsunami with accompanying inversion of topography in the overriding plate. This concept will reappear in the companion Cascadia units many times. Students interpret the post-seismic horizontal deformation field in relation to the rupture zone using a precision GPS data set. They then interpret the post-seismic vertical deformation pattern along the plate boundary using satellite-based radiometric data on coral heads, and relate this to the conceptual model of co-seismic topographic inversion.
Comparison is made with the two other magnitude 9+ earthquakes that have occurred since modern recording has been available, the 1960 M9.6 earthquake on the subduction zone east of Chile—the greatest ever recorded—and the 1964 M9.2 earthquake on the subduction zone south of Alaska. Students compile information demonstrating that the three M9+ events have all characteristics in common: patterns of seismicity, active volcanic chains, long rupture zones, mega-tsunami generation, and the characteristic co-seismic inversion of topography leading to flooding of down-dropped coastal regions.
To aid understanding of concepts and generate interest, the unit makes full use of the GIS tools, animations, diagrams, historic photos, and a lyrical—if horrific—excerpt from a novel, the plot of which is based on the 1960 Chilean earthquake.
Download project files now...
ArcGIS version
MyWorld GIS version
This material is based upon work supported by the National Science Foundation under Grant Number DUE-0521936. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.