Featured Research

from universities, journals, and other organizations

Tonga Quake Not Conducive To Tsunami

Date:
March 15, 2007
Source:
Washington University in St. Louis
Summary:
Seismologists at Washington University in St. Louis and their colleagues in Australia, Japan and Tonga have determined why a large earthquake in Tonga did not cause a large tsunami. A tsunami warning was issued around the Pacific Rim following the magnitude 8.0 earthquake on May 3, 2006, but the resulting tsunami was very minor and caused no damage. It all has to do with Tonga's tearing seafloor.

The figure shows the dynamics of a slab-tear earthquake (top), compared with a shallow thrust earthquake (bottom). The slab-tearing event typically doesn't feature an accompanying tsunami.
Credit: Image courtesy of Washington University in St. Louis

Seismologists at Washington University in St. Louis and their colleagues in Australia, Japan and Tonga have determined why a large earthquake in Tonga did not cause a large tsunami. A tsunami warning was issued around the Pacific Rim following the magnitude 8.0 earthquake on May 3, 2006, but the resulting tsunami was very minor and caused no damage.

Tsunamis generally result from shallow-thrust earthquakes, which occur when the seafloor is pushed downward beneath the land in places like Japan, Chile, Indonesia and Mexico. The researchers found instead that this earthquake was slab-tearing event — a rupturing of the down-going seafloor beneath Tonga. This explains why the tsunami was smaller than expected, and suggests that large earthquakes in Tonga may typically be of the slab-tearing variety, consistent with the lack of large historical tsunamis in Tonga.

Douglas A. Wiens, Ph.D., Washington University professor of earth and planetary sciences in Arts & Sciences, and his collaborators quickly assembled their equipment and deployed seven stations to record the aftershocks some 60 kilometers beneath the surface. Washington University technical scientist Patrick Shore and graduate student David Heeszel, along with Australian and Tongan co-workers, installed the seismographs. Shore and Heeszel sailed on a small ship for several days to deploy the seismographs on a group of islands near Ha'apai, Tonga.

"A shallow-thrust earthquake's main shock would have been shallower than what we found," Wiens said. "Because that part of the world does not want a repeat of the Sumatra experience, we wanted to determine the nature of the earthquake. Our Washington University group has done extensive analyses of Tongan earthquakes, so other researchers and the National Science Foundation got in touch quickly and we had equipment installed in early June."

"The Sumatra earthquake surprised a lot of people, and the size of the Tongan one also surprised us, so we wanted to make sure there was not a tsunami hazard in the region. If all the large earthquakes are of the slab-tearing variety like the May 2006 event, it doesn't appear that there is one."


Story Source:

The above story is based on materials provided by Washington University in St. Louis. Note: Materials may be edited for content and length.


Cite This Page:

Washington University in St. Louis. "Tonga Quake Not Conducive To Tsunami." ScienceDaily. ScienceDaily, 15 March 2007. <www.sciencedaily.com/releases/2007/03/070312091502.htm>.
Washington University in St. Louis. (2007, March 15). Tonga Quake Not Conducive To Tsunami. ScienceDaily. Retrieved September 2, 2014 from www.sciencedaily.com/releases/2007/03/070312091502.htm
Washington University in St. Louis. "Tonga Quake Not Conducive To Tsunami." ScienceDaily. www.sciencedaily.com/releases/2007/03/070312091502.htm (accessed September 2, 2014).

Share This




More Earth & Climate News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Iceland Lowers Aviation Alert on Volcano

Iceland Lowers Aviation Alert on Volcano

AFP (Sep. 1, 2014) Iceland has lowered its aviation alert on its largest volcano after a fresh eruption on a nearby lava field prompted authorities to enforce a flight ban for several hours. Duration: 01:07 Video provided by AFP
Powered by NewsLook.com
Lightning Hurts 3 on NYC Beach

Lightning Hurts 3 on NYC Beach

AP (Sep. 1, 2014) A lightning strike injured three people on a New York City beach on Sunday. The storms also delayed flights and interrupted play at the US Open tennis tournament. (Sept. 1) Video provided by AP
Powered by NewsLook.com
Thailand Totters Towards Waste Crisis

Thailand Totters Towards Waste Crisis

AFP (Sep. 1, 2014) Fears are mounting in Bangkok that poor planning and lax law enforcement are tipping Thailand towards a waste crisis. Duration: 01:21 Video provided by AFP
Powered by NewsLook.com
Melting Ice Shelves Drive Rapid Antarctic Sea Level Rise

Melting Ice Shelves Drive Rapid Antarctic Sea Level Rise

Newsy (Sep. 1, 2014) A study of almost 20 years' worth of satellite images shows Antarctic sea levels are on the rise as ice shelves continue to melt. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins