Washington state unprepared for megaquake

There is reckoned to be an 84% chance of a major earthquake during the next 50 years along the Seattle fault in Washington state, USA.

Journalists at The Seattle Times have been investigating the state’s preparedness for a major earthquake similar, or greater, in magnitude to the 2001 Nisqually earthquake.

They highlight a number of areas where much needs to be done to protect the state’s schools, hospitals and other public institutions.

The Seattle Times also suggests that the area is long overdue for a megaquake 2,000 times more powerful than the Nisqually quake. This would be a ‘full rip 9.0’ event caused by a massive shift of tectonic plates off the Pacific Coast. There has not been a Cascadia Subduction Zone earthquake since 1700, but scientists know that magnitude 8.0 quakes happen once every 250 years on average.

In 2009 geologists at Oregon State University predicted a 10% – 14% probability that the Cascadia Subduction Zone will produce an event of magnitude 9.0 or higher in the next 50 years. In 2010 further research reckoned the risk could be as high as 37% for earthquakes of magnitude 8.0 or higher.

The Seattle Times science reporter Sandi Doughton exploring this issue : Full-Rip 9.0: The Next Big Earthquake in the Pacific Northwest (2014).

SOURCE : Seattle Times – Washington state woefully unprepared for megaquake

DATE : 7 December 2016

Fault Curvature May Control Where Big Quakes Occur

Major earthquakes, magnitude 8.5 and stronger, occur where faults are mostly flat, say geologists from the University of Oregon and University of Nice Sophia Antipolis. Curvier faults, they report in the journal Science, are less likely to experience earthquakes exceeding that strength.

Large earthquakes, known as mega-quakes, were long thought to be possible only at the boundary between fast converging, young tectonic plates until two giant earthquakes. However the magnitude 9.4 quake in Indonesia in 2004 and the 9.0 quake in Japan in 2011 disconfirmed the theory.

Since then giant earthquakes have been thought to be possible on any large fault. In the new paper researchers show that the maximum size of earthquakes may be controlled by another parameter – the fault curvature.

FULL STORY : www.sciencenewsline.com/news/2016112515160013.html

DATE : 25 November 2016

SOURCE : Science Newsline