Interplate Slip Following the 2003 Tokachi‐oki Earthquake from Ocean Bottom Pressure Gauge and Land GNSS Data
Interplate Slip Following the 2003 Tokachi‐oki Earthquake from Ocean Bottom Pressure Gauge and Land GNSS Data
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根据海底压力计和陆地 GNSS 数据得出 2003 年十胜冲地震后的板间滑移
DOI：
10.1029/2018jb016328
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Hiroyuki Matsumoto
中科院分区：
文献类型：
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作者：
Yuji Itoh;Takuya Nishimura;Keisuke Ariyoshi;Hiroyuki Matsumoto
利用陆地全球导航卫星系统（GNSS）数据和使用粘弹性格林函数的两个海底压力计（OBP），对2003Mw8.0 Tokachi‐oki地震的震前、同震和7.5年的震后形变进行了建模。在千岛海沟南部，地震后的滑动分布与主震或以往大地震的震源区不重叠。在同震和震后滑动区，使用相同的板块界面几何形状来估计震前锁定。地震后滑动的时间演化用单一的对数函数来描述。同震滑动区上倾比下倾扩展的滑动衰减更快。持续的震后滑动表明，在7.5年的分析周期内，震后滑动区的板间锁定尚未完全恢复到2003年以前的状态。震后滑动历史也表明同震滑动区锁止恢复迅速。我们检查了OBP时间序列对震后形变建模的约束，发现OBP观测到的隆起需要在海沟附近发生小的震后滑动，而海沟在17世纪曾发生过一次9级海啸。OBP站点的隆起并不限制OBP站点上、下倾侧的绝对滑动量，但要求上倾侧的滑动量小于下倾侧的滑动量。我们的模型描述了陆地GNSS和OBP观测到的瞬态震后变形。
Preseismic, coseismic, and 7.5 years of postseismic deformation of the 2003Mw8.0 Tokachi‐oki earthquake are modeled using land Global Navigation Satellite System (GNSS) data and two ocean bottom pressure gauges (OBP) using viscoelastic Green's functions. The postseismic slip distribution is shown to not overlap with the main shock or the source regions of past large earthquakes along the southern part of the Kurile trench. The preseismic locking is estimated in the coseismic and postseismic slip regions using the same plate interface geometry. The temporal evolution of the postseismic slip is described with a single logarithmic function. The slip is shown to decay faster updip of the coseismic slip region compared to the downdip extension. Sustained postseismic slip indicates that the interplate locking in the postseismic slip region had not fully recovered to the pre‐2003 status in the 7.5 year analyzed period. Postseismic slip history also indicates rapid recovery of locking in the coseismic slip region. We examined the constraint of the OBP time series for the postseismic deformation modeling and found that the observed uplift at the OBP sites requires small postseismic slip near the trench, where a tsunamigenicM9 earthquake occurred in the seventeenth century. Uplift at the OBP sites does not constrain the absolute slip magnitude between the updip and downdip sides of the OBP sites but requires the slip in the updip side to be smaller than that in the downdip side. Our model describes transient postseismic deformation observed by both land GNSS and OBP.