Комплексная интерпретация временных вариаций гравитационного поля и GPS данных в области землетрясения в Кокосовой котловине (бассейн Вартон) 11.04.2012

Михайлов, В.; Diament, M.; Тимошкина, Е.; Смирнов, В.; Хайретдинов, С.

Авторы: Михайлов ВО, Diament M., Тимошкина ЕП, Смирнов ВБ, Хайретдинов СА
Сборник: Вопросы теории и практики геологической интерпретации гравитационных, магнитных и электрических полей (49-я сессия Международного семинара им. Д.Г. Успенского - В.Н. Страхова, 23-27 января, 2023 года),
Год издания: 2023
Издательство: Институт философии и права УрО РАН
Местоположение издательства: Екатеринбург
Первая страница: 245
Последняя страница: 251
Аннотация: The Cocos (Wharton) basin is situated in the north-eastern part of the Indian Ocean. In 2012it hosted the largest intraplate strike-slip earthquakes ever recorded by geophysical networks. TheMw 8.6 earthquake of April 11, 2012, was preceded by a major foreshock (Mw 7.2) on January 10and was followed two hours afterward by a Mw 8.2 event. These three large events occurred at thediffuse boundary between the Indian and Australian plates and were almost pure strike-slips on subverticalrupture surfaces. Using GRACE data, we first extracted coseismic and postseismic gravitysignals caused by these earthquakes. Then we fitted both GPS and the highest available spatialresolution of GRACE data using the geometry of the fault system suggested by Hill et al. Wesuggest a new regularization which allows to solve for a linear problem in order to invert GPS andGRACE data under constrains on the rake angle. Our inversion yields a uniform displacement fieldon all elements of a given fault plane. Our solution shows that even if the main displacementoccurred on WNW trending faults, comparable displacement also occurred on a rupture strikingNNE. Hence, we show that the deformation in this diffuse plate boundary region in 2012 wasaccommodated by displacements along both fault-systems.A viscoelastic relaxation of the asthenosphere with a Maxwell viscosity 1019 Pa∙ssuccessfully explains the postseismic displacements at GPS sites and postseismic gravity signals.The limited postseismic aftershock activity suggests small postseismic slip in the area of theWharton 2012 earthquakes on the contrary to what is often observed after large subduction event.Anyway, because a part of the observed signal could be related to afterslip, our obtained Maxwellviscosity value should be considered as a lower limit of the asthenospheric viscosity below theWharton basin.
Добавил в систему: Смирнов Владимир Борисович

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Комплексная интерпретация временных вариаций гравитационного поля и GPS данных в области землетрясения в Кокосовой котловине (бассейн Вартон) 11.04.2012статья

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