J. J. Lienkaemper
J.S. Galehouse
2003
<p><span>We summarize over 20 years of monitoring surface </span>creep<span> on </span>faults<span> of the </span>San<span> Andreas system </span>in<span> the </span>San<span> </span>Francisco<span> </span>Bay<span> </span>region<span> using </span>alinement<span> arrays. The </span>San<span> Andreas </span>fault<span> is fully locked at five sites northwest from </span>San<span> Juan Bautista, the southern end of the 1906 earthquake rupture, that is, no </span>creep<span> (< 1 mm/yr) is observed. Likewise, the </span>San<span> Gregorio, Rodgers Creek, and West Napa </span>faults<span> show no </span>creep<span>. The measured </span>creep<span> rate on the Calaveras-Paicines </span>fault<span> 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 </span>creep<span> rate reaches 14 ± 2 mm/yr but drops to ∼ 2 mm/yr near Calaveras Reservoir, where slip transfers to the southern Hayward </span>fault<span> at a maximum </span>creep<span> rate of 9 mm/yr at its south end. However, the Hayward </span>fault<span> averages only 4.6 mm/yr over most of its length. The Northern Calaveras </span>fault<span>, now creeping at 3-4 mm/yr, steps right to the Concord </span>fault<span>, 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 </span>fault<span>. The Maacama </span>fault<span> creeps at 4.4 mm/yr near Ukiah and 6.5 mm/yr </span>in<span> Willits. The central and southern segments of the Calaveras </span>fault<span> are predominantly creeping, whereas the Hayward, Northern Calaveras, and Maacama </span>faults<span> are partly locked and, along with the Rodgers Creek and </span>San<span> Andreas, have high potential for major earthquakes.</span></p>
application/pdf
10.1785/0120020226
en
Seismological Society of America
Inferences drawn from two decades of alinement array measurements of creep on faults in the San Francisco Bay Region
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