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Volcanism and large earthquakes of the Kuril-Kamchatka subduction zone viewed from spaceтезисы доклада
- Авторы: Mikhailov V., Diament M., Shapiro N., Kiseleva E., Timoshkina E.
- Сборник: Living Planet Symposium, 2019
- Тезисы
- Год издания: 2019
- Место издания: Милан, Италия
- Аннотация: We investigated seismic and volcanic processes in the Kuril-Kamchatka subduction zone using SAR interferometry, GPS and GRACE data on time varying gravity field First with the use of SAR interferometry we studied the Olutorsk MW=7.6 (Kamchatka, Russia) April 20, 2006 earthquake and two its strongest aftershocks, both of magnitude 6.6 that occurred on April 29 and May 22, 2006. The intriguing feature of these earthquakes is that surface ruptures of 140 km long showed mostly right-lateral slip whereas CMT solution revealed predominantly thrust movement. Besides, the surface ruptures dip to SE whereas aftershocks mostly occurred in a 75 km wide area to the NW from the surface ruptures. An interferogram constructed using ERS and ENVISAT images covering the main seismic event of April 20, 2006 and April 29 aftershock showed that the main LOS displacements also occurred to the NW from the ruptures mapped at the Earth` surface. We used both GPS and GRACE data to construct a coseismic rupture model and performed numerical modelling of possible postseismic viscoelastic relaxation or postseismic creep. We found that a postseismic creep along the down-dip extension of the coseismic rupture below the 100 km depth better fit GPS and gravity data. We estimated that the total displacements since the beginning of the growth of the gravity anomaly up to July 2012, is about 3.0 m in the upper part of the plate’s contact and 1.5 m in the lower part stretching to 100 km depth. The released total energy would be equivalent to Mw = 8.5 magnitude event.
- Добавил в систему: Михайлов Валентин Олегович