Slip in the 2010-2011 Canterbury earthquakes, New Zealand
Slip in the 2010-2011 Canterbury earthquakes, New Zealand
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DOI：
10.1029/2011jb008868
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发表时间：
2012-03-03
影响因子：
3.9
通讯作者：
Parsons, B.
中科院分区：
文献类型：
--
作者：
Elliott, J. R.;Nissen, E. K.;Parsons, B.
2010年9月3日的达菲尔德7.1级地震和2011年2月21日的克赖斯特彻奇6.3级地震发生在以前未知的断层上。我们使用InSAR地面位移、SAR振幅偏移、现场测绘、航空照片、卫星光学图像、激光雷达DEM和远震体波模型来约束这些地震中的断层模式。InSAR测量结果显示，与达菲尔德主震相关的多个走滑段和次级逆断层发生滑动。断层走向与gps应变场预测一致。InSAR视距位移场显示主断层破裂长约45 km，主要局限于地壳上部10 km。在4 km深度的单个断层段上高达8 m的滑动表明应力降为6-10 MPa。在每次事件中，破裂都始于逆断层段，然后继续进入走滑段。各事件的非双偶地震矩张量与InSAR确定的断层滑动双偶等效矩张量之和匹配良好。从达菲尔德和克赖斯特彻奇事件的InSAR观测得到的滑动分布显示，克赖斯特彻奇西南断层滑动有一个15公里长的间隙，如果那里存在一个未知的较大规模的断层结构，这可能会带来持续的地震危险。
The 3rd September 2010 Mw 7.1 Darfield and 21st February 2011 Mw 6.3 Christchurch (New Zealand) earthquakes occurred on previously unknown faults. We use InSAR ground displacements, SAR amplitude offsets, field mapping, aerial photographs, satellite optical imagery, a LiDAR DEM and teleseismic body-wave modeling to constrain the pattern of faulting in these earthquakes. The InSAR measurements reveal slip on multiple strike-slip segments and secondary reverse faults associated with the Darfield main shock. Fault orientations are consistent with those expected from the GPS-derived strain field. The InSAR line-of-sight displacement field indicates the main fault rupture is about 45 km long, and is confined largely to the upper 10 km of the crust. Slip on the individual fault segments of up to 8 m at 4 km depth indicate stress drops of 6-10 MPa. In each event, rupture initiated on a reverse fault segment, before continuing onto a strike-slip segment. The non-double couple seismological moment tensors for each event are matched well by the sum of double couple equivalent moment tensors for fault slip determined by InSAR. The slip distributions derived from InSAR observations of both the Darfield and Christchurch events show a 15-km-long gap in fault slip south-west of Christchurch, which may present a continuing seismic hazard if a further unknown fault structure of significant size should exist there.