Variability of the Space-Time Evolution of Slow Slip Events Off the Boso Peninsula, Central Japan, From 1996 to 2014
Variability of the Space-Time Evolution of Slow Slip Events Off the Boso Peninsula, Central Japan, From 1996 to 2014
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DOI：
10.1002/2017jb014709
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发表时间：
2018-01-01
影响因子：
3.9
通讯作者：
Fukuda, Jun'ichi
中科院分区：
文献类型：
--
作者：
Fukuda, Jun'ichi
利用全球导航卫星系统（GPS）数据反演了1996、2002、2007、2011和2013-2014年日本中部房总半岛外5次M-w 6.6-6.7慢滑事件（SSE）的时空演化。我们的分析表明，在这五个SSE中，滑移的形核方式和时空演化各不相同。2002年、2007年和2011年的SSE成核速度更快，力矩加速度比1996年的SSE高出约2-6倍，比2013-2014年的SSE高出一个数量级。此外，2002年，2007年和2011年的SSE表现出更快的时间变化在他们的滑动和力矩率，并显示出更大的地震力矩和更高的最大滑动率比1996年和2013-2014年的SSE，这表明SSE的整体演化与成核风格。沿走向的扩展/传播的滑动被确定为五个SSE，揭示了扩展/传播模式不同的事件。伴随着SSE的震群发生在高滑动速率区的下倾边缘附近，并且地震活动在缓慢滑动期间迁移，其方向和速度与滑动扩展/传播的方向和速度相似。这些地震活动与慢滑动之间的时空相关性表明，地震群是由慢滑动引起的应力变化触发的。SSE的发作和它们相关的地震活动性之间的相对时间因事件而异，并且似乎与SSE的成核类型相关。
Global Navigation Satellite System data are inverted to investigate the space-time evolution of five M-w 6.6-6.7 slow slip events (SSEs) off the Boso Peninsula, central Japan, in 1996, 2002, 2007, 2011, and 2013-2014. Our analyses reveal that the nucleation style and space-time evolution of slip vary among the five SSEs. The 2002, 2007, and 2011 SSEs nucleated more rapidly, with moment accelerations higher than those of the 1996 SSE by a factor of approximate to 2-6, and higher than those of the 2013-2014 SSE by an order of magnitude. Furthermore, the 2002, 2007, and 2011 SSEs exhibited more rapid temporal variations in their slip and moment rates and showed larger seismic moments and higher maximum slip rates than the 1996 and 2013-2014 SSEs, suggesting that the overall evolution of the SSEs is correlated with the nucleation style. The along-strike expansion/propagation of slip is identified for the five SSEs, revealing that the expansion/propagation patterns vary from event to event. The earthquake swarms accompanying the SSEs occurred near the downdip edge of high-slip-rate areas, and the seismicity migrated during slow slip with directions and speeds similar to those of the slip expansion/propagation. These space-time correlations between seismicity and slow slip suggest that the earthquake swarms were triggered by stress changes due to slow slip. The relative timing between the onsets of the SSEs and their associated seismicity varies from event to event and appears to be correlated with the nucleation style of the SSEs.