Researchers provide insight into hazard potential of large earthquakes
Scripps Institution of Oceanography, UC San Diego researchers published new findings on the role geological rock formations offshore of Japan played in producing the massive 2011 Tohoku-oki earthquake, one of only two magnitude 9 mega-earthquakes to occur in the last 50 years.
The study, published in the journal Nature, offers new information about the hazard potential of large earthquakes at subduction zones, where tectonic plates converge.
The magnitude 9 quake, which triggered a major tsunami that caused widespread destruction along the coastline of Japan, including the Fukushima nuclear plant disaster, was atypical in that it created an unusually large seismic movement, or slip, of 50 meters (164 feet) within a relatively small rupture area along the earthquake fault.
To better understand what may have caused this large movement, Scripps researchers used gravity and topography data to produce a detailed map of the geological architecture of the seafloor offshore of Japan. The map showed that the median tectonic line, which separates two distinct rock formations, volcanic rocks on one side and metamorphic rocks on the other, extends along the seafloor offshore.
The region over the earthquake-generating portion of the plate boundary off Japan is characterized by variations in water depth and steep topographic gradients of about six kilometers (3.7 miles). These gradients, according to the researchers, can hide smaller variations in the topography and gravity fields that may be associated with geological structure changes of the overriding Japan and subducting Pacific plates.
"The new method we developed has enabled us to consider how changes in the composition of Japan's seafloor crust along the plate-boundary influences the earthquake cycle," said Dan Bassett, a postdoctoral researcher at Scripps and lead author of the study.
The researchers suggest that a large amount of stress built up along the north, volcanic rock side of the median tectonic line resulting in the earthquake's large movement. The plates on the south side of the line do not build up as much stress, and large earthquakes have not occurred there.
"There's a dramatic change in the geology that parallels the earthquake cycle," said Scripps geophysicist David Sandwell, a co-author of the study. "By looking at the structures of overriding plates, we can better understand how big the next one will be."
Yuri Fialko, a professor in the Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics at Scripps and Anthony B. Watts from the University of Oxford are also co-authors on the study.
Mario Aguilera | EurekAlert!
Research icebreaker Polarstern begins the Antarctic season
09.11.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
Far fewer lakes below the East Antarctic Ice Sheet than previously believed
08.11.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly
The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
13.11.2018 | Physics and Astronomy
13.11.2018 | Health and Medicine
13.11.2018 | Life Sciences