Predicted ground motions for great earthquake in Pacific Northwest: Seattle, Victoria and Vancouver

Jun 11, 2009

A new study evaluates expected ground motion in Seattle, Victoria and Vancouver from earthquakes of magnitude 7.5 - 9.0, providing engineers and policymakers with a new tool to build or retrofit structures to withstand seismic waves from large "subduction" earthquakes off the continent's west coast.

The Cascadia subduction zone in the has produced great earthquakes of magnitude 9.0 and larger, most recently in the 1700s. Now home to millions of people and a vast infrastructure of buildings and other man-made structures, scientists seek to determine the impact of large earthquakes on the region.

To simulate ground motions from a very large earthquake on the local region, this study combined detailed analysis of ground motions recorded from smaller earthquakes in the Pacific Northwest with recorded data from a severe subduction earthquake from another region - the M8.4 2003 Tokachi-Oki quake off the coast of Japan. The authors estimate ground motions for firm ground at the three sites and provide a model that engineers can adjust for local or site-specific soil conditions.

Co-author Gail Atkinson of the University of Western Ontario describes earthquakes in the Pacific Northwest as having rich energy content. "The expected ground motion may not be very large in amplitude - the peak accelerations are not that high - but the motion will go on for a very long time," Atkinson explained. "The real hazard is that an here will affect a very large, very wide region - amplifying seismic motion and exciting vulnerable structures wherever there is an opportunity to do so."

Source: Seismological Society of America

Explore further: Microscopic organism plays a big role in ocean carbon cycling

add to favorites email to friend print save as pdf

Related Stories

Ill. earthquake a wake-up call

Apr 20, 2008

A U.S. seismologist said the earthquake that jolted the Midwest Friday is a reminder of the risks seismic events pose outside familiar quake areas.

Paired earthquakes separated in time and space

Jan 30, 2008

Earthquakes occurring at the edges of tectonic plates can trigger events at a distance and much later in time, according to a team of researchers reporting in today's issue of Nature. These doublet earthquakes may hold a ...

Recommended for you

How productive are the ore factories in the deep sea?

17 hours ago

About ten years after the first moon landing, scientists on earth made a discovery that proved that our home planet still holds a lot of surprises in store for us. Looking through the portholes of the submersible ...

NASA image: Volcanoes in Guatemala

22 hours ago

This photo of volcanoes in Guatemala was taken from NASA's C-20A aircraft during a four-week Earth science radar imaging mission deployment over Central and South America. The conical volcano in the center ...

User comments : 0

More news stories

Study links California drought to global warming

While researchers have sometimes connected weather extremes to man-made global warming, usually it is not done in real time. Now a study is asserting a link between climate change and both the intensifying California drought ...

Google+ boss leaving the company

The executive credited with bringing the Google+ social network to life is leaving the Internet colossus after playing a key role there for nearly eight years.