Imaging topographic growth by long-lived postseismic afterslip at Sefidabeh, east Iran
Imaging topographic growth by long-lived postseismic afterslip at Sefidabeh, east Iran
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DOI：
10.1002/2013tc003462
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发表时间：
2014-03-01
期刊：
影响因子：
4.2
通讯作者：
Reynolds, Kirsty
中科院分区：
文献类型：
--
作者：
Copley, Alex;Reynolds, Kirsty
本文介绍了 1994 年伊朗东部塞菲达贝地震序列后震后形变的观测结果和模型，揭示了地震周期的性质和该地区地形生长的机制。干涉合成孔径雷达观测显示断层阵列上的爬行断层运动（震后后滑）。其中一些断层可能是 1994 年盲目逆冲断层地震中破裂的断层的延伸，并穿过整个孕震层，而其他断层则较浅，破坏了同震断层的上盘。震后滑移至少容纳了埋藏同震滑移产生的部分垂直位移梯度，该位移梯度集中在大于约5公里的深度。震后余滑在地震发生后 16 年多的时间里都可见。震后隆起区域与地貌中保存的长期运动迹象之间的一致性表明，类似于我们观察到的地震周期期间的浅断层滑动控制着该地区景观的发展。浅层断层阵列上的滑动为活动逆冲断层上方短波长地形和地质结构的发育提供了机制，并且对于解释与塞菲达贝经历相似地震周期的地区产生的浅层地质特征具有重要意义。
This paper describes observations and models of the postseismic deformation following the 1994 Sefidabeh earthquake sequence in east Iran, which shed light on the nature of the earthquake cycle and the mechanisms of topographic growth in the region. Interferometric synthetic aperture radar observations show creeping fault motion (postseismic afterslip) on an array of faults. Some of these faults probably represent the extensions of those that ruptured in the blind thrust-faulting earthquakes in 1994, and cut through the entire seismogenic layer, while others are shallow and break up the hanging walls of the coseismic faults. The postseismic slip accommodates at least part of the vertical displacement gradient resulting from the buried coseismic slip, which was concentrated at depths of greater than approximate to 5km. The postseismic afterslip is visible for over 16 years following the earthquakes. Agreement between the areas of postseismic uplift and indications of long-term motion preserved in the geomorphology suggest that shallow fault slip during seismic cycles similar to the one we have observed governs the development of the landscape in the region. Slip on an array of shallow faults provides a mechanism for the development of short-wavelength topography and geological structures above active thrust faults and has important implications for the interpretation of shallow geological features produced in regions experiencing similar seismic cycles to that at Sefidabeh.