EarthRef.org Reference Database (ERR)
Development and Maintenance by the EarthRef.org Database Team

Detailed Reference Information
McGarr & Fletcher 2000
McGarr, A. and Fletcher, J.B. (2000). A method for mapping apparent stress and energy radiation applied to the 1994 Northridge Earthquake Fault Zone. Geophysical Research Letters 27: doi: 10.1029/1999GL011344. issn: 0094-8276.

Using the Northridge earthquake as an example, we demonstrate a new technique able to resolve apparent stress within subfaults of a larger fault plane. From the model of Wald et al. (1996), we estimated apparent stress for each subfault using &tgr;a=(G/&bgr;)⟨D˙⟩/2 where G is the modulus of rigidity, &bgr; is the shear wave speed, and ⟨D˙⟩ is the average slip rate. The image of apparent stress mapped over the Northridge fault plane supports the idea that the stresses causing fault slip are inhomogeneous, but limited by the strength of the crust. Indeed, over the depth range 5 to 17 km, maximum values of apparent stress for a given depth interval agree with &tgr;a(max)=0.06S(z), where S is the laboratory estimate of crustal strength as a function of depth z. The seismic energy from each subfault was estimated from the product &tgr;aDA, where A is subfault area and D its slip. Over the fault zone, we found that the radiated energy is quite variable spatially, with more than 50% of the total coming from just 15% of the subfaults. ¿ 2000 American Geophysical Union

BACKGROUND DATA FILES

Abstract

Keywords
Seismology, Earthquake dynamics and mechanics, Seismology, Earthquake parameters
Journal
Geophysical Research Letters
http://www.agu.org/journals/gl/
Publisher
American Geophysical Union
2000 Florida Avenue N.W.
Washington, D.C. 20009-1277
USA
1-202-462-6900
1-202-328-0566
service@agu.org
Click to clear formClick to return to previous pageClick to submit