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Rheological Models of Great Subduction Earthquakes from Simultaneous Inversion of Coseismic and Postseismic GPS Dataтезисы доклада
- Авторы: Steblov G.M., Vladimirova I.S.
- Сборник: American Geophysical Union (AGU) 2012 Fall Meeting
- Том: 1
- Тезисы
- Год издания: 2012
- Место издания: San Francisco
- Первая страница: T22A-04
- Аннотация: Great subduction earthquakes are usually followed by postseismic deformation which may be observed for years and decades since the earthquake. Often the coseismic stress caused by slip on the rupture is released by distributed viscoelastic relaxation in the weak upper mantle. Coseismic and postseismic surface displacements recorded by GPS observations are used as an input to model coseismic slip and postseismic relaxation. Coseismic and postseismic modeling are widely implemented as two independent steps. We developed a method of simultaneous inversion of coseismic and postseismic GPS data, which allows us to update the models of rupture and of the mantle rheology by combining both kinds of data. In forward modeling, we use the VISCO1D software of F.F. Pollitz, with the spherically symmetric, viscoelastic earth model. Here we apply our method to three great earthquakes associated with subduction: the 2006 Mw = 8.3 Kuril, 2007 Mw = 8.1 Kuril, and 2010 Mw = 8.8 Maule-Chile. The 2006 Kuril and 2010 Maule earthquakes have thrust mechanism, while the 2007 Kuril earthquake is extensional. We analyzed 4 years of continuous data of the Kuril GPS Array and 2 years of continuous data of the international GPS network in South America. As compared with the purely coseismic inversion, our approach yields additional coseismic slip on the rupture. The Maxwell viscosity of the upper mantle was estimated as 3 × 10^17 Pa s for the Kuril subduction zone; it was estimated as 6 × 10^18 Pa s for the Chile subduction zone. We predict the observable postseismic signal from the Kuril doublet for the next ~15 years; from the Maule earthquake, for several decades.
- Добавил в систему: Стеблов Григорий Михайлович