Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New findings indicate sediment composition affected the strength of Sumatran earthquake

09.07.2010
International research team studied differences between 2004 and 2005 quakes

Sumatra experiences frequent seismic activity because it is located near the boundary of two of Earth's tectonic plates. Earthquakes occur at 'subduction zones,' such as the one west of Indonesia, when one tectonic plate is forced under another--or subducts. Instead of sliding across one another smoothly, the plates stick, and energy builds up until they finally slip or 'rupture', releasing that stored energy as an earthquake.

These earthquakes can generate tsunamis when the seafloor moves up or down rapidly. But why do some earthquakes, such as the 2004 Sumatra "Boxing Day Tsunami", create large hazards, while others do not?

Three months after the catastrophic December 2004 earthquake and tsunami events, another strong, albeit smaller, quake occurred immediately to the south, but this earthquake triggered only a local tsunami.

"Many people wondered why the 2004 quake was so large," said Sean Gulick, a geophysicist from the University of Texas at Austin. "Perhaps a more interesting question is: why wasn't it larger? Why did the rupture occur as two events instead of one large one?"

With support from the National Science Foundation (NSF), Gulick joined an international research team to try to figure out why there were two quakes, and what made them so different. Working aboard the research vessel Sonne, the scientists used seismic instruments to study layers of sediment beneath the seafloor with sound waves.

The researchers found that the fault surface where the two tectonic plates meet, called a décollement, has different properties in the two earthquake rupture regions. In the southern part of the 2004 area, the décollement imaging results show a bright reflection, while the décollement in the 2005 area does not. This difference in the images suggests changes in the composition of the rocks--or the fault itself--between the rupture areas. These characteristics may partially explain why the areas did not rupture together and may also contribute to differences in the tsunamis produced by both events.

Scientists believe this difference in composition, combined with several other factors, resulted in the fault slipping over a much wider part of the margin and farther seaward in the 2004 event.They suspect that because more earth moved, more of the seafloor moved and more water was displaced, resulting in a larger tsunami.

Compared to similar studies of other subduction zones around the world, the team believes the region of the 2004 Sumatra earthquake is very unusual, and that tsunami hazards may be particularly high in this area.

The results of their study appear in the July 9 edition of the journal Science. The paper's lead author is Simon Dean, of the University of Southampton (UK). Researchers from the University of Texas at Austin (US), the Agency for the Assessment and Application of Technology (Indonesia), and the Indonesia Institute for Sciences also contributed to the work.

Lisa Van Pay | EurekAlert!
Further information:
http://www.nsf.gov

More articles from Earth Sciences:

nachricht NASA eyes Pineapple Express soaking California
24.02.2017 | NASA/Goddard Space Flight Center

nachricht 'Quartz' crystals at the Earth's core power its magnetic field
23.02.2017 | Tokyo Institute of Technology

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

New pop-up strategy inspired by cuts, not folds

27.02.2017 | Materials Sciences

Sandia uses confined nanoparticles to improve hydrogen storage materials performance

27.02.2017 | Interdisciplinary Research

Decoding the genome's cryptic language

27.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>