Category: News

314 Year Anniversary of the Great 1700 Cascadia Subduction Zone Earthquake

January 26, 2014 marked the 314-Year Anniversary of the last Cascadia Earthquake

SEATTLE— The last Cascadia Subduction Zone earthquake occurred one hundred years before Lewis and Clark saw the Pacific Ocean. It was a time when native traditions spoke of the ground shaking and the waters rising. There were no bridges to fall and no schools, hospitals and other critical infrastructure in tsunami inundation zones. It was a time when Cascadia was much more resilient than today. “The very advances that are the foundations of our modern communities create vulnerability along with convenience” said Michael Kubler, Cascadia Region Earthquake Workgroup (CREW) President. “The revised Cascadia scenario is a crucial tool for regional leaders to use in developing policies and plans for the next earthquake.”

Events over the last few years have expanded our understanding of earthquake science and the hazards faced by our region from a future Cascadia Subduction Zone earthquake. The Cascadia Subduction Zone extends along the coastlines of northern California, Oregon, Washington, and southern British Columbia. There’s no doubt that Cascadia is capable of producing earthquakes and tsunamis on the same scale as the magnitude 8.8 earthquake off Chile in 2010 and the magnitude 9.0 quake that devastated the east coast of Japan in 2011.

Cascadia’s last great earthquake occurred on January 26, 1700—stresses have been building on the fault ever since. While the full extent of the earthquake hazard was not realized until the 1980s, the Cascadia subduction zone is now one of the most closely studied and monitored regions in the world. “In 2005 CREW first published the Cascadia earthquake scenario, but so much new information has emerged that an update was needed” said Heidi Kandathil, CREW Executive Director. The newly updated Cascadia Scenario joins the list of other free products developed by CREW to help the region’s residents, schools, businesses, planners, and emergency managers prepare for future earthquakes. The Scenario and other materials are available online at http://tinyurl.com/m34v2ex.

###

For more about CREW and the new Cascadia Subduction Zone Scenario, seeCascadia Factsheet.

Evacuation potential in SW Washington communities from Cascadia tsunami hazards

A new article in the journal Natural Hazards documents variations in population exposure in coastal communities of Pacific and Grays Harbor counties to Cascadia-related tsunami hazards as a function of modeled pedestrian travel time to safety. Results suggest that successful evacuations may be possible in some communities assuming slow walking speeds, are plausible in others if travel speeds are increased, and are unlikely in another set of communities given the large distances and short time horizon. Communities can use these results to help prioritize tsunami risk-reduction efforts, such as education and training in areas where evacuations are plausible and vertical-evacuation strategies in areas where they currently are not.

More information can be found at http://www.springerlink.com/content/a6177520x5k6080t/ or by emailing the lead author at nwood@usgs.gov.