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.

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 July 25, 2014 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 July 25, 2014).

Share This




More Earth & Climate News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

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
Higgins Breaks Record at Mt. Washington

Higgins Breaks Record at Mt. Washington

Driving Sports (July 24, 2014) Subaru Rally Team USA drivers David Higgins and Travis Pastrana face off against a global contingent of racers at the annual Mt. Washington Hillclimb in New Hampshire. Includes exclusive in-car footage from Higgins' record attempt. Video provided by Driving Sports
Powered by NewsLook.com
Storm Kills Three, Injures 20 at Virginia Campground

Storm Kills Three, Injures 20 at Virginia Campground

Reuters - US Online Video (July 24, 2014) A likely tornado tears through an eastern Virginia campground, killing three and injuring at least 20. Linda So 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:
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