Featured Research

from universities, journals, and other organizations

'Fossil Earthquakes' Abundant

Date:
January 29, 2009
Source:
Seismological Society of America
Summary:
Rocks formed only under the extreme heat and friction during earthquakes, called pseudotachylytes, may be more abundant than previously reported, according to new research focused on eight faults found in the Sierra Nevada.

Rocks formed only under the extreme heat and friction during earthquakes, called pseudotachylytes, may be more abundant than previously reported, according to new research focused on eight faults found in the Sierra Nevada.

Related Articles


Geologists have previously debated whether these rocks are rarely produced or not based on an apparent absence in the rock record, most likely brought about by the difficulty in identifying them. Only a small fraction of the energy released in an earthquake is consumed by seismic waves, the formation of pseudotachylytes reveals the importance of the heat generated by the earthquake process.

Pseudotachylytes form by frictional melting during co-seismic faulting at significant depths in the crust. They are not easy to identify, requiring evidence that the fault rock has passed through a melt phase. They are generated by frictional heating of the slip surface, the melting of which may account for a significant proportion of energy released during an earthquake.

Past surveys of the Sierra Nevada, which reported an absence of pseudotachylytes, have focused on the geometry and mechanics of the faults rather than the geological details of the rock types and composition. However, the authors of this study report an abundance of pseudotachylytes throughout the area. The pseudotachylytes they describe range from easily identified to impossible to identify from field data alone. The authors suggest further study of pseudotachylytes will ultimately reveal more about energy partitioning during earthquakes.


Story Source:

The above story is based on materials provided by Seismological Society of America. Note: Materials may be edited for content and length.


Journal Reference:

  1. Kirkpatrick et al. Pseudotachylytes: Rarely Generated, Rarely Preserved, or Rarely Reported? Bulletin of the Seismological Society of America, 2009; 99 (1): 382 DOI: 10.1785/0120080114

Cite This Page:

Seismological Society of America. "'Fossil Earthquakes' Abundant." ScienceDaily. ScienceDaily, 29 January 2009. <www.sciencedaily.com/releases/2009/01/090128160816.htm>.
Seismological Society of America. (2009, January 29). 'Fossil Earthquakes' Abundant. ScienceDaily. Retrieved March 2, 2015 from www.sciencedaily.com/releases/2009/01/090128160816.htm
Seismological Society of America. "'Fossil Earthquakes' Abundant." ScienceDaily. www.sciencedaily.com/releases/2009/01/090128160816.htm (accessed March 2, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Monday, March 2, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Whale-Watching Scientists Spot Baby Orca

Whale-Watching Scientists Spot Baby Orca

AP (Feb. 28, 2015) Researchers following endangered killer whales spotted a baby orca off the coast of Washington state, the third birth documented this winter but still leaving the population dangerously low. (Feb. 28) Video provided by AP
Powered by NewsLook.com
Bridge Collapses Due to Flooding in Bolivia

Bridge Collapses Due to Flooding in Bolivia

Reuters - News Video Online (Feb. 28, 2015) Heavy rain and flooding sweep through parts of Bolivia causing damage and leaves more than 2,000 people homeless. Sophia Soo reports. Video provided by Reuters
Powered by NewsLook.com
Death Toll from Afghan Avalanches Tops 200

Death Toll from Afghan Avalanches Tops 200

AFP (Feb. 27, 2015) More than 200 people have been killed in a series of avalanches triggered by heavy snowfall in Afghanistan. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
France, Philippines Call for Agreement on Climate Change

France, Philippines Call for Agreement on Climate Change

Reuters - News Video Online (Feb. 27, 2015) The presidents of France and the Philippines issue a joint appeal for a binding agreement on climate change. Katie Sargent reports. Video provided by Reuters
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