scholarly journals Detecting seismogenic stress evolution and constraining fault zone rheology in the San Andreas Fault following the 2004 Parkfield earthquake

Author(s):  
Taka'aki Taira ◽  
Paul G. Silver ◽  
Fenglin Niu ◽  
Robert M. Nadeau
Geology ◽  
1975 ◽  
Vol 3 (8) ◽  
pp. 437 ◽  
Author(s):  
Robert L. Kovach ◽  
Amos Nur ◽  
Robert L. Wesson ◽  
Russell Robinson

1981 ◽  
Vol 71 (1) ◽  
pp. 95-116 ◽  
Author(s):  
Allan G. Lindh ◽  
David M. Boore

abstract A reanalysis of the available data for the 1966 Parkfield, California, earthquake (ML=512) suggests that although the ground breakage and aftershocks extended about 40 km along the San Andreas Fault, the initial dynamic rupture was only 20 to 25 km in length. The foreshocks and the point of initiation of the main event locate at a small bend in the mapped trace of the fault. Detailed analysis of the P-wave first motions from these events at the Gold Hill station, 20 km southeast, indicates that the bend in the fault extends to depth and apparently represents a physical discontinuity on the fault plane. Other evidence suggests that this discontinuity plays an important part in the recurrence of similar magnitude 5 to 6 earthquakes at Parkfield. Analysis of the strong-motion records suggests that the rupture stopped at another discontinuity in the fault plane, an en-echelon offset near Gold Hill that lies at the boundary on the San Andreas Fault between the zone of aseismic slip and the locked zone on which the great 1857 earthquake occurred. Foreshocks to the 1857 earthquake occurred in this area (Sieh, 1978), and the epicenter of the main shock may have coincided with the offset zone. If it did, a detailed study of the geological and geophysical character of the region might be rewarding in terms of understanding how and why great earthquakes initiate where they do.


1983 ◽  
Vol 73 (6A) ◽  
pp. 1701-1720
Author(s):  
R. Feng ◽  
T. V. McEvilly

Abstract A seismic reflection profile crossing the San Andreas fault zone in central California was conducted in 1978. Results are complicated by the extreme lateral heterogeneity and low velocities in the fault zone. Other evidence for severe lateral velocity change across the fault zone lies in hypocenter bias and nodal plane distortion for earthquakes on the fault. Conventional interpretation and processing methods for reflection data are hard-pressed in this situation. Using the inverse ray method of May and Covey (1981), with an initial model derived from a variety of data and the impedance contrasts inferred from the preserved amplitude stacked section, an iterative inversion process yields a velocity model which, while clearly nonunique, is consistent with the various lines of evidence on the fault zone structure.


2008 ◽  
Vol 98 (6) ◽  
pp. 2948-2961 ◽  
Author(s):  
C. C. Tsai ◽  
R. D. Catchings ◽  
M. R. Goldman ◽  
M. J. Rymer ◽  
P. Schnurle ◽  
...  

2004 ◽  
Vol 31 (12) ◽  
pp. n/a-n/a ◽  
Author(s):  
Yong-Gang Li ◽  
John E. Vidale ◽  
Elizabeth S. Cochran

Geophysics ◽  
1967 ◽  
Vol 32 (2) ◽  
pp. 297-301 ◽  
Author(s):  
S. N. Domenico

A gravity profile was obtained from closely spaced readings along a traverse approximately nine miles in length across the San Andreas fault zone immediately south of Palmdale, California in the western Mojave Desert. Corrected gravity values show a slight but distinctive minimum associated with the fault zone which may be attributed to the reduced density of the shattered rock masses in the fault zone. The existence of this minimum suggests that major fault zones may be traced across terrain, on which surface expression of the fault does not exist, by successive profiles across the suspected position of the fault zone.


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