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2010年2月27日智利马乌莱M8.8地震后,我们认为监测到的GRACE卫星相对轨道的微小变化量足以用于描述震后重力场变化。地震后在震中以东500km空间区域内观测到-5μGal的重力异常。同震模型认为,长波长尺度的重力负异常主要是地壳扩张和大陆地表沉陷的结果。有限断层同震模型认为,近海地区重力变化取决于地表抬升和内部形变,由于这两种因素对重力场影响相反,因而由此计算的重力异常相当微小。我们的研究目标是利用大尺度重力观测数据来解释大地震期间的地球内部变化,研究方法是将极难获得的地震形变长波长观测值与大地测量数据和地震数据相结合进行分析研究。
After the M8.8 Mauch earthquake in Chile, February 27, 2010, we believe that a small change in the relative orbit of the observed GRACE satellites is sufficient to describe changes in the gravitational field after the earthquake. Gravity anomalies of -5 μGal were observed in the 500 km space east of the epicenter after the earthquake. The coseismic model states that the negative long-wavelength gravity anomalies are mainly the result of the crustal expansion and the continental subsidence. According to the finite fault coseismic model, the gravity change in the offshore area depends on the surface uplift and internal deformation. Since these two factors have opposite effects on the gravitational field, the gravity anomalies thus calculated are rather small. Our research goal is to use large-scale gravity observations to explain the earth’s interior variability during major earthquakes. The research approach is to combine the extremely long-wavelength observations of seismic deformation with geodetic and seismic data.