Abstract Inversion of the coseismic slip distribution is important for understanding seismogenic mechanisms. In this study, the geometric parametersand uncertainties for the 2015 Gorkha earthquake in Nepal were inverted using a Bayesian approach. The coseismic fault slip distribution was inverted based on triangular dislocations from interferometrc synthetic aperture radar (InSAR) and Global Positioning System (GPS) surface displacement measurements. The inversion results show that the rupture propagated southeast for approximately 140 km, with most of the slip constrained within 30 - 40 km along the dip direction. There are two peak slips in the slip distribution: a ∼5.9 m slip located ∼50 km southeast of the epicenter at a depth of 10.2 km, and a ∼6.32 m slip located ∼100 km southeast of the epicenter at a depth of 10 km. Near the M w 7.3 aftershock, the rupture propagated to the north and southeast. The gap in slip formed between the mainshock and the M w 7.3 aftershock is similar to the shape of a “crocodile with an open mouth”. The results of the triangular dislocation model can explain the GPS-based coseismic displacements and the InSAR deformation field when compared with a classic rectangular dislocation, with a 10.6 cm reduction in the average residual of the InSAR data and a 2 cm reduction in the average residual of the GPS deformation. Compared to the geometry of a ramp—flat—ramp structure, we postulate that both a single-segment and multiple-segments are possible near Kathmandu.

中文翻译：

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根据 InSAR 和 GPS 测量估计的 2015 Mw7.8 Gorkha（尼泊尔）地震的断层滑动分布

摘要 同震滑动分布的反演对于理解地震发生机制很重要。在这项研究中，使用贝叶斯方法反演了 2015 年尼泊尔廓尔喀地震的几何参数和不确定性。基于干涉仪合成孔径雷达 (InSAR) 和全球定位系统 (GPS) 表面位移测量的三角位错，对同震断层滑动分布进行了反演。反演结果表明，破裂向东南传播约140 km，大部分滑动沿倾角方向限制在30～40 km范围内。滑移分布中有两个峰值滑移：位于震中东南约 50 km 深度 10.2 km 处的 ∼5.9 m 滑移和位于震中东南约 100 km 深度 10 km 处的∼6.32 m 滑移. 靠近 M w 7。3 号余震，破裂向北和东南传播。主震与M w 7.3余震之间形成的滑动间隙类似于“张开嘴的鳄鱼”的形状。与经典矩形位错相比，三角位错模型的结果可以解释基于 GPS 的同震位移和 InSAR 变形场，InSAR 数据的平均残差减少 10.6 cm，平均残差减少 2 cm GPS 变形。与坡道-平坦-坡道结构的几何形状相比，我们假设在加德满都附近可能存在单段和多段。与经典矩形位错相比，三角位错模型的结果可以解释基于 GPS 的同震位移和 InSAR 变形场，InSAR 数据的平均残差减少 10.6 cm，平均残差减少 2 cm GPS 变形。与坡道-平坦-坡道结构的几何形状相比，我们假设在加德满都附近可能存在单段和多段。与经典矩形位错相比，三角位错模型的结果可以解释基于 GPS 的同震位移和 InSAR 变形场，InSAR 数据的平均残差减少 10.6 cm，平均残差减少 2 cm GPS 变形。与坡道-平坦-坡道结构的几何形状相比，我们假设在加德满都附近可能存在单段和多段。