Jade Sridevi, Mir Ramees R, Vivek Chiranjeevi G, Shrungeshwara T S, Parvez I A, Chandra Rakesh, Babu D Suri, Gupta S Vishal, Rajana Siva Sai Kumar, Gaur V K
CSIR-4PI, CSIR Fourth Paradigm Institute (Formerly CSIR-CMMACS), Wind Tunnel Road, Bangalore, India.
Department of Earth Sciences, University of Kashmir, Srinagar, India.
Sci Rep. 2020 Oct 21;10(1):17927. doi: 10.1038/s41598-020-74776-5.
We present GPS velocities in Kashmir valley and adjoining regions from continuous Global Positioning System (cGPS) network during 2008 to 2019. Results indicate total arc normal shortening rates of ~ 14 mm/year across this transect of Himalaya that is comparable to the rates of ~ 10 to 20 mm/year reported else-where in the 2500 km Himalaya Arc. For the first time in Himalayas, arc-parallel extension rate of ~ 7 mm/year was recorded in the Kashmir valley, pointing to oblique deformation. Inverse modeling of the contemporary deformation rates in Kashmir valley indicate oblique slip of ~ 16 mm/year along the decollement with locking depth of ~ 15 km and width of ~ 145 km. This result is consistent with the recorded micro-seismicity and low velocity layer at a depth of 12 to 16 km beneath the Kashmir valley obtained from collocated broadband seismic network. Geodetic strain rates are consistent with the dislocation model and micro-seismic activity, with high strain accumulation (~ 7e-08 maximum compression) to the north of Kashmir valley and south of Zanskar ranges. Assuming the stored energy was fully released during 1555 earthquake, high geodetic strain rate since then and observed micro-seismicity point to probable future large earthquakes of Mw ~ 7.7 in Kashmir seismic gap.
我们展示了2008年至2019年期间通过连续全球定位系统(cGPS)网络获得的克什米尔山谷及毗邻地区的GPS速度。结果表明,喜马拉雅山这一断面的总弧法向缩短率约为14毫米/年,这与在2500公里长的喜马拉雅山弧其他地方报道的约10至20毫米/年的速率相当。在喜马拉雅山首次记录到克什米尔山谷的弧平行伸展率约为7毫米/年,表明存在斜向变形。对克什米尔山谷当代变形率的反演模型表明,沿滑脱面的斜向滑动速率约为16毫米/年,锁定深度约为15公里,宽度约为145公里。这一结果与从并置的宽带地震网络获得的克什米尔山谷下方12至16公里深处记录的微震活动和低速层一致。大地测量应变率与位错模型和微震活动一致,在克什米尔山谷以北和赞斯卡山脉以南有高应变积累(最大压缩约为7e - 08)。假设在1555年地震期间储存的能量完全释放,自那时以来的高地测量应变率和观测到的微震活动表明克什米尔地震空白区未来可能发生震级约为Mw 7.7的大地震。