Featured Research

from universities, journals, and other organizations

Tohoku grim reminder of potential for Pacific Northwest North American megaquake

Date:
February 21, 2012
Source:
University of Nevada, Reno
Summary:
The March 11, 2011 Tohoku earthquake is a grim reminder of the potential for another strong-motion mega-earthquake along the Pacific Northwest coast, geophysicists say.

The March 11, 2011 Tohoku earthquake is a grim reminder of the potential for another strong-motion mega-earthquake along the Pacific Northwest coast, geophysicist John Anderson of the University of Nevada, Reno told members of the American Association for the Advancement of Science in a lecture at their annual conference in Vancouver, B.C. February 19.

"The Cascadia fault line, which runs from southern Canada all the way to Northern California, could have much stronger ground-motions than those observed in Japan," Anderson, a professor of geophysics, said. "The Tohoku earthquake, while only half the length of Cascadia, is an analog for an earthquake that could happen here in the northwestern United States and southwestern British Columbia."

Both Japan and Cascadia sit above subduction zones that dip at a low angle beneath the land. One might consider them roughly mirror images, he said.

"In this mirror image, one can see that if the same earthquake occurred in Cascadia, the fault would rupture to a significant distance inland, since the Cascadia trench sits much closer to the coastline than the trench off the coast of Japan, Anderson said. "Some models predict that a Cascadia earthquake will not rupture so far under the land, but if it does, the data from the Tohoku earthquake predict stronger ground motions along our west coast than those seen in Japan. In any case, the ground motions from Tohoku are critical for understanding the seismic hazard here in Vancouver, and in Seattle, and Portland, and Eureka and all points in between."

In Cascadia, the last great earthquake occurred on January 26, 1700. Based on the size of the tsunami, the magnitude of that earthquake was about magnitude 9.0.

"Although the average interval is apparently larger, earthquakes of this size in the past may have recurred with intervals of as small as about 300 years. So it would not be a scientific surprise if such an event were to occur in the near future," Anderson said. "If you live in the Pacific northwest, look at the videos of Tohoku as a reminder to be prepared for an earthquake and tsunami."

Anderson, who studies strong ground-motions, spent nine months recently as a visiting research professor at the Tokyo University, home of one of the world's premier seismology programs. Before coming to the University of Nevada, Reno in 1998, he earned his doctorate in geophysics from Columbia University and has held appointments at the California Institute of Technology, University of Southern California and the University of California at San Diego.

In his presentation at the AAAS conference, about the strong ground motions in the Tohoku earthquake, he discusses the significance of the data, the effects of the source on the nature of the data, the effects of site response, and some discussion of the engineering effects.

"There have of course been other mega-earthquakes, but this is by far the best-recorded," he said. "The Japanese event will undoubtedly stand as the best-recorded megaquake for a long time to come, both because megaquakes are rare and because no place is as well instrumented as the islands of Japan."

For instance, the strong ground motions that could be generated along Cascadia, unfortunately, might not be observed nearly as thoroughly, since the strong motion instrumentation in most of the Cascadia region is sparse compared to Japan.

Anderson said that in spite of the occasional records with high accelerations, damage to structures from the shaking in Tohoku was reduced by high building standards, and because the ground velocities caused by the earthquake were not high enough to cause damage even at sites with peak acceleration over 1g.


Story Source:

The above story is based on materials provided by University of Nevada, Reno. Note: Materials may be edited for content and length.


Cite This Page:

University of Nevada, Reno. "Tohoku grim reminder of potential for Pacific Northwest North American megaquake." ScienceDaily. ScienceDaily, 21 February 2012. <www.sciencedaily.com/releases/2012/02/120221125407.htm>.
University of Nevada, Reno. (2012, February 21). Tohoku grim reminder of potential for Pacific Northwest North American megaquake. ScienceDaily. Retrieved August 23, 2014 from www.sciencedaily.com/releases/2012/02/120221125407.htm
University of Nevada, Reno. "Tohoku grim reminder of potential for Pacific Northwest North American megaquake." ScienceDaily. www.sciencedaily.com/releases/2012/02/120221125407.htm (accessed August 23, 2014).

Share This




More Earth & Climate News

Saturday, August 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Airlines on Iceland Volcano Alert

Airlines on Iceland Volcano Alert

Reuters - Business Video Online (Aug. 22, 2014) Iceland evacuates an area north of the country's Bardarbunga volcano, as the country's civil protection agency says it cannot rule out an eruption. Authorities have already warned airlines. As Joel Flynn reports, ash from the eruption of the Eyjafjallajokull volcano in 2010 shut down much of Europe's airspace for six days. Video provided by Reuters
Powered by NewsLook.com
Endangered Red Wolves Face Uncertain Future

Endangered Red Wolves Face Uncertain Future

AP (Aug. 22, 2014) A federal judge temporarily banned coyote hunting to save endangered red wolves, but local hunters say that the wolf preservation program does more harm than good. Meanwhile federal officials are reviewing its wolf program in North Carolina. (Aug. 22) Video provided by AP
Powered by NewsLook.com
Coal Gas Boom in China Holds Climate Risks

Coal Gas Boom in China Holds Climate Risks

AP (Aug. 22, 2014) China's energy revolution could do more harm than good for the environment, despite the country's commitment to reducing pollution and curbing its carbon emissions. (Aug. 22) Video provided by AP
Powered by NewsLook.com
Microbrewery Chooses Special Can for Its Beer

Microbrewery Chooses Special Can for Its Beer

AP (Aug. 22, 2014) Aluminum giant, Novelis, has partnered with Red Hare Brewing Company to introduce the first certified high-content recycled beverage can. (Aug. 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins