Abstract
Spatial and temporal variations of aseismic fault creep influence the size and timing of large earthquakes along partially coupled faults. To solve for a time-dependent model of creep on the Hayward fault, we invert 18 years of surface deformation data (1992-2010), obtained by interferometric processing of 52 and 50 SAR images acquired by the ERS1/2 and Envisat satellites, respectively, and surface creep data obtained at 19 alinement and 4 creepmeter stations. For multi-temporal analysis of the SAR data we developed a method for identifying stable pixels using wavelet multi-resolution analysis. We also implement a variety of wavelet-based filters for reducing the effects of environmental artifacts. Using a reweighted least squares approach, we inverted the interferometric data to generate a time series of surface deformation over the San Francisco Bay Area with a precision of better than a few millimeters. To jointly invert the InSAR displacement time series and the surface creep data for a time-dependent model of fault creep, we use a robust inversion approach combined with a Kalman filter. The time-dependent model constrains a zone of high slip deficit that may represent the locked rupture asperity of past and future M≈7 earthquakes. We identify several additional temporal variations in creep rate along the Hayward fault, the most important one being a zone of accelerating slip just northwest of the major locked zone. We estimate that a slip-rate deficit equivalent to Mw 6.3-6.8 has accumulated on the fault, since the last event in 1868.
Original language | English (US) |
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Pages (from-to) | 1733-1746 |
Number of pages | 14 |
Journal | Journal of Geophysical Research: Solid Earth |
Volume | 118 |
Issue number | 4 |
DOIs | |
State | Published - Apr 1 2013 |
Keywords
- Hayward
- InSAR
- Time-dependent creep
- inverse modeling
ASJC Scopus subject areas
- Geophysics
- Geochemistry and Petrology
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science