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.
机构:
CALTECH, Seismol Lab, Pasadena, CA 91125 USACALTECH, Seismol Lab, Pasadena, CA 91125 USA
Jolivet, R.
Simons, M.
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机构:
CALTECH, Seismol Lab, Pasadena, CA 91125 USACALTECH, Seismol Lab, Pasadena, CA 91125 USA
Simons, M.
Agram, P. S.
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机构:
CALTECH, Jet Prop Lab, Pasadena, CA USACALTECH, Seismol Lab, Pasadena, CA 91125 USA
Agram, P. S.
Duputel, Z.
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机构:
CALTECH, Seismol Lab, Pasadena, CA 91125 USA
Inst Phys Globe Strasbourg, UdS, Strasbourg, France
EOST CNRS UMR, Strasbourg, FranceCALTECH, Seismol Lab, Pasadena, CA 91125 USA
Duputel, Z.
Shen, Z. -K.
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机构:
Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USACALTECH, Seismol Lab, Pasadena, CA 91125 USA