Filling the Gap in Cascadia: The Emergence of Low‐Amplitude Long‐Term Slow Slip
Filling the Gap in Cascadia: The Emergence of Low‐Amplitude Long‐Term Slow Slip
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填补卡斯卡迪亚的空白：低幅度长期慢滑移的出现
DOI：
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发表时间：
2021
影响因子：
3.5
通讯作者：
D. Schmidt
中科院分区：
文献类型：
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作者：
C. Nuyen;D. Schmidt
在全球的几个俯冲带已经观察到长期的慢滑事件，它们在大型逆冲断层的应变释放中起着不可或缺的作用。然而，在卡斯卡迪亚俯冲带长期缓慢滑动的证据仍然难以捉摸。在这里，我们对2006年至2019年的13年GNSS时间序列数据进行了系统分析，并提供了在卡斯卡迪亚俯冲带上至少发生一次低振幅长期慢滑事件的证据，以及其他不太确定的可能性。从2012年中期开始，在卡斯卡迪亚南部观测到1.5年的瞬变，一组沿海GNSS站向西移动约2毫米。这些数据被模拟为发生在板块界面15-35 km深度的6.4 Mw慢滑事件，只是先前识别的短期慢滑和震颤的上倾。该事件与南开俯冲带类似的长期瞬变事件具有许多共同特征。然而，与其他地方的大事件相比，Cascadia的总断层滑动幅度要小一个数量级，这使得Cascadia的长期慢滑动检测具有挑战性。虽然在精细化的数据集中还有其他向西的长时间瞬变，但地表位移低于噪声水平，或者空间上仅限于几个邻近的站点，这使得解释不明确。
Long‐term slow slip events have been observed at several subduction zones around the globe, where they play an integral part in strain release along megathrust faults. Nevertheless, evidence for long‐term slow slip has remained elusive in the Cascadia subduction zone. Here we conduct a systematic analysis of 13 years of GNSS time series data from 2006 to 2019 and present evidence of at least one low‐amplitude long‐term slow slip event on the Cascadia subduction zone, with the possibility of others that are less resolved. Starting in mid‐2012, a 1.5‐year transient is observed in southern Cascadia, with a group of coastal GNSS stations moving ∼2 mm to the west. The data are modeled as a Mw 6.4 slow slip event occurring at 15–35 km depth on the plate interface, just updip of previously recognized short‐term slow slip and tremor. The event shares many characteristics with similar long‐term transient events on the Nankai subduction zone. However, the total fault slip amplitude is an order‐of‐magnitude smaller in Cascadia when compared to large events elsewhere, making long‐term slow slip detection challenging in Cascadia. While there are other westward long‐duration transients in the refined data set, the surface displacements are below the level of the noise or are limited spatially to a few neighboring stations, making interpretation unclear.
影响因子：
5.2
作者：
Materna, Kathryn;Bartlow, Noel;Buergmann, Roland
通讯作者：
Buergmann, Roland