Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tohoku grim reminder of potential for Pacific Northwest megaquake

22.02.2012
University of Nevada, Reno geophysicist presents study at science conference in Vancouver, B.C.

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. Sunday.

"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 prestigious Tokyo University, home of one of the world's premier seismology programs. Before coming to the Universtiy 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.

Nevada's land-grant university founded in 1874, the University of Nevada, Reno has an enrollment of 18,000 students and is ranked in the top tier of the nation's best universities. Part of the Nevada System of Higher Education, the University has the system's largest research program and is home to the state's medical school. With outreach and education programs in all Nevada counties and with one of the nation's largest study-abroad consortiums, the University extends across the state and around the world. For more information, visit www.unr.edu.

Mike Wolterbeek | EurekAlert!
Further information:
http://www.unr.edu

More articles from Earth Sciences:

nachricht Climate satellite: Tracking methane with robust laser technology
22.06.2017 | Fraunhofer-Gesellschaft

nachricht How reliable are shells as climate archives?
21.06.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>