Peltzer G, Crampé F, King G
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA. Institut de Physique du Globe de Paris, France.
Science. 1999 Oct 8;286(5438):272-276. doi: 10.1126/science.286.5438.272.
Satellite synthetic aperture radar (SAR) interferometry shows that the magnitude 7.6 Manyi earthquake of 8 November 1997 produced a 170-kilometer-long surface break with up to 7 meters of left-lateral slip, reactivating a N76 degrees E quaternary fault in western Tibet. The radar interferometric map reveals asymmetric, along-strike displacement profiles between the two sides of the surface rupture, a pattern that cannot be explained with linear elastic theory. This observation suggests that the elastic moduli of the crust in tension and in compression are different because of the presence of cracks in the crust at shallow depth. A model indicates that a ratio of 2 between compressive and tensile elastic moduli can account for the observed asymmetry, a ratio that is consistent with laboratory and borehole measurements.
卫星合成孔径雷达（SAR）干涉测量显示，1997年11月8日发生的里氏7.6级曼尼地震造成了一条长达170公里的地表破裂带，最大左旋错距达7米，重新激活了西藏西部一条北东76度的第四纪断层。雷达干涉测量图揭示了地表破裂两侧沿走向的位移剖面不对称，这种模式无法用线弹性理论解释。这一观测结果表明，由于浅部地壳中存在裂缝，地壳在拉伸和压缩状态下的弹性模量不同。一个模型表明，压缩弹性模量与拉伸弹性模量之比为2可以解释观测到的不对称性，这一比值与实验室和钻孔测量结果一致。
