Slow and Go: Pulsing slip rates on the creeping section of the San Andreas Fault

被引:25
|
作者
Turner, Ryan C. [1 ]
Shirzaei, Manoochehr [2 ]
Nadeau, Robert M. [1 ]
Buergmann, Roland [1 ,3 ]
机构
[1] Univ Calif Berkeley, Berkeley Seismol Lab, Berkeley, CA 94720 USA
[2] Arizona State Univ, Sch Earth & Space Explorat, Tempe, AZ USA
[3] Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 94720 USA
基金
美国国家科学基金会;
关键词
creep; deformation; InSAR; repeating earthquakes; San Andreas Fault; Plate Boundary Observatory; PARKFIELD; CALIFORNIA; SYSTEM; INSAR; EARTHQUAKES; UPLIFT; GPS;
D O I
10.1002/2015JB011998
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
Rising and falling slip rates on the creeping section of the San Andreas Fault have been inferred from variations of recurrence intervals of characteristically repeating microearthquakes, but this observation has not previously been confirmed using modern geodetic data. Here we report on observations of this pulsing slip obtained from advanced multitemporal interferometric synthetic aperture radar (InSAR) data, confirmed using continuous GPS sites of the Plate Boundary Observatory. The surface deformation time series show a strong correlation to the previously documented slip rate variations derived from repeating earthquakes on the fault interface, at various spatial and temporal scales. Time series and spectral analyses of repeating earthquake and InSAR data reveal a quasiperiodic pulsing with a roughly 2year period along some sections of the fault, with the earthquakes on the fault interface lagging behind the far-field deformation by about 6months. This suggests a temporal delay between the pulsing crustal strain generated by deep-seated shear and the time-variable slip on the shallow fault interface, and that at least in some places this process may be cyclical. There exist potential impacts for time-dependent seismic hazard forecasting in California and, as it becomes better validated in the richly instrumented natural laboratory of the central San Andreas Fault, the process used here will be even more helpful in characterizing hazard and fault zone rheology in areas without California's geodetic infrastructure.
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页码:5940 / 5951
页数:12
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