DNR geologists cautious about predictions of possible ’12th man’ earthquake this Sunday

earthquake faults near CenturyLink Field
The two horizontal, dark blue dotted lines (CLICK map to enlarge) show the approximate location of earthquake faults near CenturyLink Field (Qwest Field on this older map). Image: DNR

 As University of Washington seismologists prepare to monitor seismometers at CenturyLink Field in Seattle for evidence of fan-induced “earthquakes” during this Sunday’s NFC conference championship game between the Seattle Seahawks and San Francisco 49ers, some may wonder if the noise and shaking that Seattle fans generate during games could set off an actual earthquake.

The answer? Quite unlikely. But earthquakes do occur. Washington State is after all situated at a convergent continental margin, the collisional boundary between two tectonic plates, known as the Cascadia subduction zone (where the North America and the Juan de Fuca plates meet just offshore from the Washington coast). Closer to the stadium is the Seattle Fault (directly beneath the city), the Southern Whidbey Island Fault, the Tacoma Fault … you get the idea. We are in a seismically active area.

DNR geologists continue to map the numerous earthquake fault zones around the state to learn more about these hazards, but other than Seahawk home games, they are not predicting any earthquakes.

Many precursors to earthquakes have been studied in the hope that they will allow us to make accurate predictions. These precursors include small magnitude earthquakes, water levels in wells, concentrations of radon and helium in ground water, changes in natural electromagnetic radiation, and animal behavior. Although sensors at CenturyLink Field recorded shaking on January 8, 2011, during the 67-yard touchdown run by the Seahawks’ Marshawn Lynch (helping Seattle defeat New Orleans in an NFC Wild Card game), and again last Sunday, this particular precursor has not been scientifically studied.

While some claim (without verification) to be able to predict earthquakes, none of the precursors or other prediction methods offered up have been consistent. Therefore, DNR geologists will continue to study existing earthquake faults and related formations. This Sunday, for example, many of them will be gathered around large screen televisions to view the Seahawks-49ers game… in the spirit of scientific research, of course.

View maps of known earthquake faults and other known hazards in Washington State and their potential impacts (such as a 7.2 magnitude earthquake on the Seattle Fault) using the maps on the Washington State Interactive Geologic Portal.

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