A FIELD ALERT - Geologists Plan to Study Doty Fault Line Between Centralia and Chehalis in Washington State

Health & Safety - Mining, Environmental, & Cybersecurity

Date posted: 09/08/15

Kaylee Osowski reports that if the particular fault is active, proposed Chehalis River Dam could be affected. She attended a presentation in a dimmed room in front of a slideshow with an audience primarily made up of Lewis County fire chiefs, and a state geologist presenting, Timothy J. Walsh, Chief Geologist with the Washington State Department of Natural Resources. He said a fault line between Centralia and Chehalis that crosses Interstate 5 has been researched very little. It is actually unknown whether or not the Doty Fault is active. Plans are underway, however, to study this fault zone more intensively, and if it turns out that this is active, it is a fault zone that would be capable of an earthquake between 6.5 and 7 (magnitude), said Walsh. Part of the reason to study the fault more is to learn how it would affect the proposed water retention dam on the Chehalis River near Pe Ell. Whether this is active would be very important in … what the design of that should be, he said. Scientists have recently started using LiDAR technology, which measures distance with a laser by analyzing the light reflected, to study faults and have not done so yet for the Doty Fault. More research has been completed on the active Saint Helens Seismic Zone, which is partially located in Lewis County and has a capacity for a magnitude 7.0 earthquake. In the more populated West Lewis County, a Saint Helens earthquake is estimated to cause little to no damage. He said Lewis County should expect to see only moderate damage from an earthquake of the entirety of the Cascadia subduction zone. In fact, he said, if an earthquake of the entire Cascadia subduction zone were to occur, Washington would likely not be as affected as the two states south of Washington. He also said that the Pacific Northwest is not overdue for an earthquake of the entire zone as some reports have stated....? The threat of large tsunami along the coast lines is real.