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 Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

nachricht Modeling magma to find copper
13.01.2017 | Université de Genève

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Explaining how 2-D materials break at the atomic level

18.01.2017 | Materials Sciences

Data analysis optimizes cyber-physical systems in telecommunications and building automation

18.01.2017 | Information Technology

Reducing household waste with less energy

18.01.2017 | Ecology, The Environment and Conservation

VideoLinks
B2B-VideoLinks
More VideoLinks >>>