Why do earthquakes stop?

Feb 06, 2008

The underlying structure of a fault determines whether an earthquake rupture will jump from one fault to another, magnifying its size and potential devastation. Understanding why some earthquakes terminate along a fault, while others jump or step-over a gap to another fault, is essential to forecasting the seismic hazard of complex fault systems, such as the San Andreas Fault.

In a paper published in this issue of BSSA (Bulletin of the Seismological Society of America), author David Oglesby of University of California at Riverside suggests that the pattern of stress at the end of the primary fault can strongly affect an earthquake’s ability to jump to a secondary fault. He suggests that a smooth, gradual decrease in stress along a rupture results in slower rupture deceleration, less strain, less generation of seismic waves, and lowers the likelihood that the earthquake will jump to another fault.

In contrast, a stress pattern that terminates suddenly leads to abrupt rupture termination, higher strain, more seismic radiation, and a higher likelihood of the rupture jumping to a secondary fault. The results of this numerical study illustrate the importance of the slip gradient and the acceleration of the rupture front in determining the probability of a rupture jumping from one fault segment to another.

Source: Seismological Society of America

Explore further: Experts express concern over cyclone trends in the British-Irish Isles

Related Stories

Supercycles in subduction zones

May 06, 2015

When tectonic plates collide, they produce earthquakes like the recent one in Nepal. Researchers at ETH Zurich are providing new ways to explain how and why earthquake supercycles occur in zones where one ...

Recommended for you

Satellite sees smoky skies over World Cup soccer

6 hours ago

Soccer fever gripped the U.S. at the same time as the smoke from Canadian wildfires gripped the skies over Vancouver, British Columbia. This was the site of the 2015 FIFA Women's World Cup Finals on July ...

NASA sees Nangka become a typhoon

12 hours ago

Tropical Storm Nangka strengthened to a typhoon in the Northwestern Pacific Ocean just after NASA's Aqua satellite passed overhead on July 6. Infrared data from the AIRS instrument showed very cold cloud ...

NASA's infrared look at strengthening Typhoon Chan-Hom

12 hours ago

During the early morning hours on July 6, Chan-Hom was a strong tropical storm. Infrared data from NASA's Aqua satellite showed very powerful thunderstorms that hinted at intensification, and later in the ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

out7x
1 / 5 (1) Feb 07, 2008
Realistically, the type of fault, amount of slip, determines resulting stress pattern.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.