He Chuansong, Dong Shuwen, Wang Yanghua
Institute of Geophysics, CEA, Beijing, 100081, China.
State Key Laboratory for Mineral Deposits Research, Nanjing University, Nanjing, 210093, China.
Sci Rep. 2019 May 6;9(1):6967. doi: 10.1038/s41598-019-43476-0.
We apply teleseismic P-wave tomography to reconstruct the velocity structure of the Longmenshan area. Our results show possible large-scale delamination beneath the Songpan-Ganzi and Qiangtang terranes, which induced upwelling asthenosphere. Upwelling asthenosphere might have led to lower crust heating, facilitating eastward extrusion of the Songpan Ganzi terrane resulting in localized deformation and uplift along the Longmenshan orogenic belt. We suggest that the eastward extrusion of the Songpan-Ganzi terrane against the rigid lithospheric root of the Sichuan Basin results in stress accumulation and release, leading to large earthquakes in the Longmenshan area.
我们应用远震P波层析成像技术来重建龙门山地区的速度结构。我们的结果显示,松潘-甘孜地块和羌塘地块下方可能存在大规模的拆沉作用,这引发了软流圈地幔上涌。软流圈地幔上涌可能导致下地壳升温,促使松潘-甘孜地块向东挤出,从而在龙门山造山带沿线产生局部变形和隆升。我们认为,松潘-甘孜地块向东挤压四川盆地刚性岩石圈根部,导致应力积累和释放,从而引发龙门山地区的大地震。