Scaling relations for seismic cycles on mid-ocean ridge transform faults
Figure S1: Rayleigh waves for the 2003 and 2008 Gofar Transform earthquakes at GSN stations and differential arrival time measurements and fits for the optimal estimate of the separation between the event centroids. (763.3Kb)
Figure S2: Rayleigh waves for the 1985 and 2000 Blanco Transform earthquakes at GSN stations and differential arrival time measurements and fits for the optimal estimate of the separation between the event centroids. (754.8Kb)
Boettcher, Margaret S.
McGuire, Jeffrey J.
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Mid-ocean ridge transform faults (RTFs) have thermal structures that vary systematically with tectonic parameters, resulting in predictable seismic characteristics and clear seismic cycles. We develop a scaling relation for repeat time, tR, of the largest expected earthquake, MC: tR = μ−1Δσ2/3CMc1/3AT1/4V−1, where μ is the shear modulus, Δσ is the stress drop, CMc is a constant, AT is the area above 600°C, and V is the slip rate. We identify repeating MC earthquakes by measuring differential arrival times of first orbit Rayleigh waves to determine centroid offsets between pairs of events. Comparing our observations of tR (5–14 years for earthquakes on Gofar and Blanco RTFs) with predictions from our scaling relation, we can constrain RTF stress drops. Specific tests of this scaling relation are proposed for earthquakes on Blanco, Gofar, Discovery, and Clipperton RTFs, which are all expected to have large ruptures in the next few years.
Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 36 (2009): L21301, doi:10.1029/2009GL040115.
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Boettcher, Margaret S.; Jordan, T. H. (American Geophysical Union, 2004-12-09)A mid-ocean ridge transform fault (RTF) of length L, slip rate V, and moment release rate dot above M can be characterized by a seismic coupling coefficient χ = A E/A T, where A E ∼ dot above M/V is an effective seismic ...
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