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.

Related Articles


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 October 31, 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 October 31, 2014).

Share This



More Earth & Climate News

Friday, October 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How A Chorus Led Scientists To A New Frog Species

How A Chorus Led Scientists To A New Frog Species

Newsy (Oct. 30, 2014) A frog noticed by a conservationist on New York's Staten Island has been confirmed as a new species after extensive study and genetic testing. Video provided by Newsy
Powered by NewsLook.com
Raw: Hawaii Lava Approaching Village Road

Raw: Hawaii Lava Approaching Village Road

AP (Oct. 30, 2014) The lava flow on the Big Island of Hawaii was 225 yards from Pahoa Village Road on Wednesday night. The lava is slowing down but still approaching the village. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Endangered Carpathian Ponies Are Making a Comeback in Poland

Endangered Carpathian Ponies Are Making a Comeback in Poland

AFP (Oct. 29, 2014) At the foot of the rugged Carpathian mountains near the Polish-Ukrainian border, ranchers and scientists are trying to protect the Carpathian pony, known as the Hucul in Polish. Duration: 02:17 Video provided by AFP
Powered by NewsLook.com
Deadly Mudslide in Sri Lanka Buries Houses

Deadly Mudslide in Sri Lanka Buries Houses

AP (Oct. 29, 2014) A mudslide triggered by monsoon rains buried scores of workers' houses at a tea plantation in central Sri Lanka on Wednesday, killing at least 10 people and leaving more than 250 missing, an official said. (Oct. 29) Video provided by AP
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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