Fialko Yuri, Sandwell David, Simons Mark, Rosen Paul
Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093, USA.
Nature. 2005 May 19;435(7040):295-9. doi: 10.1038/nature03425.
Our understanding of the earthquake process requires detailed insights into how the tectonic stresses are accumulated and released on seismogenic faults. We derive the full vector displacement field due to the Bam, Iran, earthquake of moment magnitude 6.5 using radar data from the Envisat satellite of the European Space Agency. Analysis of surface deformation indicates that most of the seismic moment release along the 20-km-long strike-slip rupture occurred at a shallow depth of 4-5 km, yet the rupture did not break the surface. The Bam event may therefore represent an end-member case of the 'shallow slip deficit' model, which postulates that coseismic slip in the uppermost crust is systematically less than that at seismogenic depths (4-10 km). The InSAR-derived surface displacement data from the Bam and other large shallow earthquakes suggest that the uppermost section of the seismogenic crust around young and developing faults may undergo a distributed failure in the interseismic period, thereby accumulating little elastic strain.
我们对地震过程的理解需要深入洞察构造应力如何在发震断层上积累和释放。我们利用欧洲航天局Envisat卫星的雷达数据，推导出了伊朗巴姆6.5级地震产生的全矢量位移场。对地表变形的分析表明，沿这条20公里长的走滑破裂带，大部分地震矩释放发生在4 - 5公里的浅部深度，但破裂并未穿出地表。因此，巴姆地震可能代表了“浅部滑动亏损”模型的一个极端情况，该模型假定最上部地壳中的同震滑动系统地小于发震深度（4 - 10公里）处的滑动。来自巴姆地震及其他大型浅源地震的InSAR反演地表位移数据表明，年轻且正在发育的断层周围发震地壳的最上部在间震期可能会经历分布式破坏，从而积累很少的弹性应变。
