Coos County Tsunami Maps Now Available

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The Oregon Department of Geology and Mineral Industries has completed tsunami inundation maps for all of Coos County. These maps show modeled extents for local-source (Cascadia Subduction Zone) and distant-source (Alaska) tsunami inundation scenarios. These maps incorporate all the best tsunami science available, including recent publications regarding the Cascadia Subduction Zone, updated computer simulation models, and knowledge gained from the 2004 Sumatra, 2010 Chile, and 2011 Tohoku earthquakes and tsunamis.

The maps provide information including estimated tsunami wave height time series charts and a measurement of the exposure each community has to the various tsunami scenarios: counting the number of buildings that are inundated by each scenario. The ODGMI hopes that the public, planners, emergency managers and first responders, elected officials and other local decision makers will use these detailed and innovative TIM maps to mitigate risk and to reduce the loss of life and property.

Each publication includes two plates.
Plate 1 displays five scenarios, labeled as “T-shirt sizes” (S, M, L, XL, and XXL), of the impact of Cascadia Subduction Zone tsunamis that reflect the full range of what was experienced in the past and will be encountered in the future. The geologic record shows that the amount of time that has passed since the last great Cascadia earthquake (312 years since January 26, 1700) is not a reliable indicator of the size of the next one, so the size ranges are intended to fully bracket what might happen next.

Plate 2 shows tsunami inundation scenarios for two distant-source tsunamis that were modeled and originate in Alaska. These distant tsunamis are not nearly as dangerous as the local ones, as Oregonians will have several hours instead of only minutes to evacuate and the tsunamis themselves are much smaller. For these reasons DOGAMI’s focus is on the big Cascadia events. If the ground shakes for an extended period of time, don’t wait for more warning, evacuate to high ground as fast as possible. To learn more about these publications, visit:

This entry was posted on Thursday, January 3rd, 2013 and is filed under Local News, State News.