A Magnitude 7.1 Earthquake in the Tacoma Fault Zone—A Plausible Scenario for Downtown Vashon

Table of Contents

This is (nearly) the title of the latest USGS fact sheet #3023 summarizing what could happen if a 7.1 earthquake happened along the Tacoma Fault Zone, as recently modeled by scientists.

“The U.S. Geological Survey and cooperating scientists have recently assessed the effects of a magnitude 7.1 earthquake on the Tacoma Fault Zone in Pierce County, Washington. A quake of comparable magnitude struck the southern Puget Sound region about 1,100 years ago, and similar earthquakes are almost certain to occur in the future. The region is now home to hundreds of thousands of people, who would be at risk from the shaking, liquefaction, landsliding, and tsunamis caused by such an earthquake. The modeled effects of this scenario earthquake will help emergency planners and residents of the region prepare for future quakes.” - Report’s Abstract

Some key findings for Vashon:

- unlike the deep 2001 6.8 Nisqually earthquake, this could be shallow (more aftershocks & damaging)

- Max tsunami run-up along the southern edge of Vashon and Maury Islands could be 2-5 meters, occurring maybe 5 minutes after the quake.

- We’re near the center of this hypothetical, but plausible scenario.

Tags :
comments powered by Disqus

Related Posts

Study reveals melt welts dynamics inside larger earthquakes

U.S. seismologists at CA’s Scripps Institution of Oceanography have released a study indicating fault zones weaken in select locations shortly after a fault reaches an earthquake tipping point. This can then transform a smaller series of quakes into a large mega-quake.

Read More

Five nuke plants in quake zones

Five active U.S. nuclear reactors -- the Diablo Canyon Power Plant and San Onofre Nuclear Generating Station in California; the South Texas Project near the Gulf Coast; the Waterford Steam Electric Station in Louisiana; and the Brunswick Steam Electric Plant in North Carolina -- are situated in seismic activity-prone zones.

Read More

NZ earthquake illustrates risks for U.S. west coast

The recent 6.3 magnitude earthquake in Christchurch, New Zealand, killed many more people and caused far more damage than the September 2010 7.1 magnitude earthquake which struck the same area; the reason: even though this earthquake was weaker than last year's event, it was much shallower; was situated directly under Christchurch; hit during the lunch hour when more people were exposed to damage; and shook sediments that were prone to "liquefaction," which can magnify the damage done by the ground shaking; scientists say the same description nicely fits many major cities and towns in Washington, Oregon, California, and British Columbia.

Read More