Modeling afterslip and aftershocks following the 1992 Landers earthquake

• Published in: Journal of Geophysical Research 2007-07, Vol.112 (B7), p.n/a
• Main Authors: Perfettini, H., Avouac, J.-P.
• Format: Article
• Language: English
• Subjects: 1992 Landers earthquake; aftershocks; afterslip; Astrophysics; Earth sciences; Earth, ocean, space; Exact sciences and technology; GPS; postseismic deformation; Sciences of the Universe
• ISSN: 0148-0227; 2156-2202
• DOI: 10.1029/2006JB004399

One way to probe the rheology of the lithosphere and fault zones is to analyze the temporal evolution of deformation following a large earthquake. In such a case, the lithosphere responds to a known stress change that can be assessed from earthquake slip models constrained from seismology and geodesy. Here, we model the postseismic response of a fault zone that is assumed to obey a rate‐strengthening rheology, where the frictional stress varies as aσ ln(), being the deformation rate and aσ > 0 a rheological parameter. The model is simple enough that these parameters can be estimated by inversion of postseismic geodetic data. We apply this approach to the analysis of geodetic displacements following the Mw7.3, 1992, Landers earthquake. The model adjusts well the measured displacements and implies aσ ≈ 0.47–0.53 MPa. In addition, we show that aftershocks and afterslip follow the same temporal evolution and that the spatiotemporal distribution of aftershocks is consistent with the idea that they are driven by reloading of the seismogenic zone resulting from frictional afterslip.