Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Migrating low-frequency tremors observed at shallow subduction interface

08.07.2015

Slow episodic slip probably occurs in the plate boundary

A University of Tokyo research group has discovered slow-moving low-frequency tremors which occur at the shallow subduction plate boundary in Hyuga-nada, off east Kyushu. This indicates the possibility that the plate boundary in the vicinity of the Nankai Trough is slipping episodically and slowly (over days or weeks) without inducing a strong seismic wave.


Distribution of shallow low-frequency tremors detected by the ocean bottom seismometer network. Yellow squares show the locations of ocean bottom seismometers. Circles indicate the distribution of occurrence of shallow low-frequency tremors, while the color of the circle indicates the time of occurrence. © 2015 Yusuke Yamashita.

It was thought that the shallow part of the plate boundary was completely “uncoupled,” being able to slowly slip relative to the neighboring plate. However, after the 2011 Great East Japan Earthquake, it was discovered that is not entirely correct, and it is very important, in particular in the Nankai Trough, an area in which a major earthquake is expected, to understand the coupling state of the plate boundary.

Hyuga-nada is located off east Kyushu in the western part of the Nankai Trough, a highly seismically active area in which M7-class interplate earthquakes occur every few decades, but interplate slip at the shallow plate boundary in this region is insufficiently understood.

A research group comprising Project Researcher Yusuke Yamashita, Assistant Professor Tomoaki Yamada, Professor Masanao Shinohara and Professor Kazushige Obara at the University of Tokyo Earthquake Research Institute and researchers at Kyushu University, Kagoshima University, Nagasaki University, and the National Research Institute for Earth Science and Disaster Prevention, carried out ocean bottom seismological observation using 12 ocean bottom seismometers installed on the seafloor of Hyuga-nada from April to July 2013.

The research group discovered migrating (moving) shallow low-frequency tremors which are thought to be triggered by slow episodic slipping (slow slip event) at the shallow plate boundary. The shallow tremors had similar migration properties to deep low-frequency tremors that occur at the deep subducting plate interface, and that they also occurred synchronized in time and space with shallow very-low-frequency tremors that also thought to be triggered by slow slip events.

These observations indicate that episodic slow slip events are probably occurring at the shallow plate boundary in the vicinity of the Nankai Trough.

After the 2011 Great East Japan Earthquake, a fundamental review of the shallow plate boundary interface is required. These new findings provide important insight into slip behavior at a shallow plate boundary and will improve understanding and modeling of subduction megathrust earthquakes and tsunamis in the future.

This research was published in the American journal Science on May 8, 2015.

Paper

Yusuke Yamashita, Hiroshi Yakiwara, Youichi Asano, Hiroshi Shimizu, Kazunari Uchida, Shuichiro Hirano, Kodo Umakoshi, Hiroki Miyamachi, Manami Nakamoto, Miyo Fukui, Megumi Kamizono, Hisao Kanehara, Tomoaki Yamada, Masanao Shinohara, Kazushige Obara, "Migrating tremor off southern Kyushu as evidence for slow slip of a shallow subduction interface", Science Vol. 348 no. 6235 pp. 676-679, doi: 10.1126/science.aaa4242.


Associated links
U Tokyo Research article

Euan McKay | ResearchSEA

More articles from Earth Sciences:

nachricht More than 100 years of flooding and erosion in 1 event
28.03.2017 | Geological Society of America

nachricht Satellites reveal bird habitat loss in California
28.03.2017 | Duke University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Transport of molecular motors into cilia

28.03.2017 | Life Sciences

A novel hybrid UAV that may change the way people operate drones

28.03.2017 | Information Technology

NASA spacecraft investigate clues in radiation belts

28.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>