Tremor‐genic slow slip regions may be deeper and warmer and may slip slower than non‐tremor‐genic regions
Tremor‐genic slow slip regions may be deeper and warmer and may slip slower than non‐tremor‐genic regions
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致震慢滑动区域可能比非致震区域更深、更温暖，并且滑动速度可能更慢
DOI：
10.1002/2015gc005895
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
E. Syracuse
中科院分区：
文献类型：
--
作者：
E. Montgomery‐Brown;E. Syracuse
慢滑动事件（SSE）在世界范围内被观测到，并且经常与构造震颤相吻合。然而，缺乏观测到的构造震颤的SSE的显著例子发生在夏威夷的Kallauea火山下面、日本的房总半岛、加州的圣安德烈斯断层上的圣胡安鲍蒂斯塔附近，以及最近在厄瓜多尔中部。这些SSE在许多方面与其他全球SSE相似（例如，规模或持续时间），但缺乏在其他地方观察到的同期构造地震;相反，它们引发了成群的常规地震。我们调查了可能将这些非致震SSE与那些与构造震颤相关的SSE区分开的物理条件，包括滑动速度、压力、温度、流体和断层粗糙度，尽管我们不能消除构造震颤在高衰减区域可能被掩盖的可能性。在Keslauea火山和房索半岛的SSE滑动速度（分别为10−6 m/s和10−7 m/s）是世界上最快的SSE。Kampallauea火山、博索半岛和厄瓜多尔中部也是世界上最浅的SSE，因此在其各自的慢滑带中具有较低的围压和较低的温度。液体也可能有助于震颤的产生，在Kamplauea或Boso没有发现相应的高vp/vs区。我们认为，相对较快的滑动速度在Keslauea火山和房总半岛的结果从特定的物理条件，也可能是负责触发群的定期地震附近的慢滑，而不同的条件下产生较慢的SSE速度在其他地方，并触发构造震颤。
Slow slip events (SSEs) are observed worldwide and often coincide with tectonic tremor. Notable examples of SSEs lacking observed tectonic tremor, however, occur beneath Kīlauea Volcano, Hawaii, the Boso Peninsula, Japan, near San Juan Bautista on the San Andreas Fault, California, and recently in Central Ecuador. These SSEs are similar to other worldwide SSEs in many ways (e.g., size or duration), but lack the concurrent tectonic tremor observed elsewhere; instead, they trigger swarms of regular earthquakes. We investigate the physical conditions that may distinguish these non‐tremor‐genic SSEs from those associated with tectonic tremor, including slip velocity, pressure, temperature, fluids, and fault asperities, although we cannot eliminate the possibility that tectonic tremor may be obscured in highly attenuating regions. Slip velocities of SSEs at Kīlauea Volcano (∼10−6 m/s) and Boso Peninsula (∼10−7 m/s) are among the fastest SSEs worldwide. Kīlauea Volcano, the Boso Peninsula, and Central Ecuador are also among the shallowest SSEs worldwide, and thus have lower confining pressures and cooler temperatures in their respective slow slip zones. Fluids also likely contribute to tremor generation, and no corresponding zone of high vp/vs has been noted at Kīlauea or Boso. We suggest that the relatively faster slip velocities at Kīlauea Volcano and the Boso Peninsula result from specific physical conditions that may also be responsible for triggering swarms of regular earthquakes adjacent to the slow slip, while different conditions produce slower SSE velocities elsewhere and trigger tectonic tremor.