thumbnail

Inferences drawn from two decades of alinement array measurements of creep on faults in the San Francisco Bay Region

Bulletin of the Seismological Society of America

By:
and

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time
  • Download citation as: RIS

Abstract

We summarize over 20 years of monitoring surface creep on faults of the San Andreas system in the San Francisco Bay region using alinement arrays. The San Andreas fault is fully locked at five sites northwest from San Juan Bautista, the southern end of the 1906 earthquake rupture, that is, no creep (< 1 mm/yr) is observed. Likewise, the San Gregorio, Rodgers Creek, and West Napa faults show no creep. The measured creep rate on the Calaveras-Paicines fault from Hollister southward is either 6 or ??? 10 mm/yr, depending on whether the arrays cross all of the creeping traces. Northward of Hollister, the central Calaveras creep rate reaches 14 ?? 2 mm/yr but drops to ??? 2 mm/yr near Calaveras Reservoir, where slip transfers to the southern Hayward fault at a maximum creep rate of 9 mm/yr at its south end. However, the Hayward fault averages only 4.6 mm/yr over most of its length. The Northern Calaveras fault, now creeping at 3-4 mm/yr, steps right to the Concord fault, which has a similar rate, 2.5-3.5 mm/yr, which is slightly slower than the 4.4 mm/yr rate on its northward continuation, the Green Valley fault. The Maacama fault creeps at 4.4 mm/yr near Ukiah and 6.5 mm/yr in Willits. The central and southern segments of the Calaveras fault are predominantly creeping, whereas the Hayward, Northern Calaveras, and Maacama faults are partly locked and, along with the Rodgers Creek and San Andreas, have high potential for major earthquakes.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Inferences drawn from two decades of alinement array measurements of creep on faults in the San Francisco Bay Region
Series title:
Bulletin of the Seismological Society of America
Volume
93
Issue:
6
Year Published:
2003
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Bulletin of the Seismological Society of America
First page:
2415
Last page:
2433
Number of Pages:
19