Featured Research

from universities, journals, and other organizations

Increase in microearthquakes in California found after Chilean quake

Date:
March 1, 2011
Source:
Georgia Institute of Technology
Summary:
By studying seismographs from the earthquake that hit Chile last February, Earth scientists have found a statistically significant increase of microearthquakes in central California in the first few hours after the main shock. The observation provides an additional support that seismic waves from distant earthquakes could also trigger seismic events on the other side of the Earth.

By studying seismographs from the earthquake that hit Chile last February, earth scientists at the Georgia Institute of Technology have found a statistically significant increase of microearthquakes in central California in the first few hours after the main shock. The observation provides an additional support that seismic waves from distant earthquakes could also trigger seismic events on the other side of Earth.

The results may be found online in the journal Geophysical Research Letters.

It has been well known that microearthquakes can be triggered instantaneously by distant earthquakes. However, sometimes the triggered events could occur long after the passage of the direct surface waves that take the shortest path on Earth's surface. There are several other explanations out there about how such delayed triggering occurs. Some involve the redistribution of pore fluids and triggered aseismic creep, while others simply consider them as aftershocks of the directly triggered events. But the group from Georgia Tech found something different.

"From our research, we've concluded the delayed triggering that occurs in the first few hours after an earthquake could be caused by multiple surface waves traveling back and forth around the Earth multiple times," said Zhigang Peng, assistant professor in the School of Earth and Atmospheric Sciences at Georgia Tech.

In a previous paper, also published in Geophysical Research Letters last December, Peng's research group found that the direct surface waves of the Chilean earthquake triggered seismic activity in central California. In this new study, Peng's group looked beyond the direct surface waves and focused on secondary and tertiary waves that return after traveling across the globe multiple times. In addition, they went beyond earthquake information published in the U.S. Geological Survey catalog and instead studied the seismographs.

"So when you look at the events that have been reported in the catalog, you won't see this effect," said Peng. "But if you look at the seismographs, you'll see many small events and notice that they occurred mostly when those multiple surface waves arrived."

Peng said that the finding is significant because it also suggests that scientists can look beyond the direct surface waves and understand that those later-arriving waves could affect the seismic activity on the other side of Earth. But his team believes that seismic waves circle the globe only for large earthquakes. They are currently examining other regions and quakes to see just how widespread this effect is.

Peng's research group includes graduate students Chunquan Wu and Chastity Aiken. Their research was supported by the National Science Foundation.


Story Source:

The above story is based on materials provided by Georgia Institute of Technology. Note: Materials may be edited for content and length.


Journal Reference:

  1. Zhigang Peng, Chunquan Wu, Chastity Aiken. Delayed triggering of microearthquakes by multiple surface waves circling the Earth. Geophysical Research Letters, 2011; 38 (4) DOI: 10.1029/2010GL046373

Cite This Page:

Georgia Institute of Technology. "Increase in microearthquakes in California found after Chilean quake." ScienceDaily. ScienceDaily, 1 March 2011. <www.sciencedaily.com/releases/2011/02/110225082930.htm>.
Georgia Institute of Technology. (2011, March 1). Increase in microearthquakes in California found after Chilean quake. ScienceDaily. Retrieved July 26, 2014 from www.sciencedaily.com/releases/2011/02/110225082930.htm
Georgia Institute of Technology. "Increase in microearthquakes in California found after Chilean quake." ScienceDaily. www.sciencedaily.com/releases/2011/02/110225082930.htm (accessed July 26, 2014).

Share This




More Earth & Climate News

Saturday, July 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Virginia Governor Tours Tornado Aftermath

Virginia Governor Tours Tornado Aftermath

AP (July 25, 2014) Virginia Gov. Terry McAuliffe toured the Cherrystone Family Camping and RV Resort on the Chesapeake Bay today, a day after it was hit by a tornado. The storm claimed two lives and injured dozens of others. (July 25) Video provided by AP
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Bill Gates: Health, Agriculture Key to Africa's Development

Bill Gates: Health, Agriculture Key to Africa's Development

AFP (July 24, 2014) Health and agriculture development are key if African countries are to overcome poverty and grow, US software billionaire Bill Gates said Thursday, as he received an honourary degree in Ethiopia. Duration: 00:36 Video provided by AFP
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