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Reveal of the pre-seismic phase of the seismic cycle from space geodetic observations over the area of Tohoku earthquake 2011тезисы доклада
- Авторы: Steblov G.M., Sdelnikova I.A., Lobkovsky L.I.
- Сборник: American Geophysical Union (AGU) 2018 Fall Meeting
- Серия: https://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/341311
- Тезисы
- Год издания: 2018
- Издательство: American Geophysical Union
- Местоположение издательства: United States
- Первая страница: T41H-0395
- Аннотация: The long-term satellite geodetic observations that have been collected by globally distributed GPS tracking sites over the past decades significantly improved our understanding of the dynamics of many seismically active regions. Comparison of the surface displacement velocities with the plate convergence rate in subduction zones confirmed spatial and temporal irregularities of the mechanical coupling in the interplate contact zones. To relate the above velocities we used dislocation models of deformation in elastic or viscoelastic medium, and this enables constraining the geometry of the interplate coupling in subduction zone from the observed surface displacements. Such inversion has a stable physically feasible solution when been regularized by constraining the solution norm, with spatial discretization adequate to the tracking network density. Also, we retain the statistical agreement between the observational equations residuals and the errors of the raw measurements. To distinguish temporal variations of the interplate coupling in the observable surface motion the effects of various mechanisms also should be filtered, such as coseismic jumps, postseismic transient response, seasonal periodic disturbances and instrumental noise. To filter the raw time series we use regression analysis assuming known time-dependent features of each process contributing into the total surface motion. Applying the described approach to observations over Japanese satellite geodetic network provided by the Geospatial Information Agency of Japan we identified specific spatial-temporal deformations preceding the great Tohoku earthquake in 2011. Localization of the focal zone of this strongest earthquake within Japan subduction zone is characterized by high lateral gradient of the interplate coupling, that emerged before the event, which shows the possibility to capture instrumentally the pre-seismic phase of the seismic cycle.
- Добавил в систему: Стеблов Григорий Михайлович