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: Climate change does not cause extreme winters, new study shows

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

Image: Aral Sea from orbit

7 hours ago

This multitemporal Sentinel-1A radar image shows the Aral Sea, located on the border between Kazakhstan and Uzbekistan in Central Asia.

IceBridge overflies Norwegian camp on drifting sea ice

10 hours ago

Studying sea ice in the Fram Strait, a passage between Greenland and Svalbard that is the main gateway for Arctic sea ice into the open ocean, is not easy. In this area, not only does ice flow southward quickly ...

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.