On June 22, 2022, the Mw6.2 earthquake in southeastern Afghanistan caused a severe disaster. We used the Sentinel-1A ascending and descending track images of the European Space Agency and interferometric synthetic aperture radar (InSAR) to obtain the coseismic surface deformation field of the earthquake, which showed that the earthquake caused complex ruptures of multiple faults and various types. Using the dislocation model of the elastic half-space, we determined the focal parameters and slip distribution on the fault plane of this event. The results reveal that: (1) the seismogenic fault of this event is an unknown fault on the northeastern edge of the Katawaz microblock; (2) The slip on the fault plane is mainly in the range of 0–8 km along the dip, with maximum slips about 2 m at a depth of 2 km, which projected on the surface is 69.44°E, 32.96°N. This event suggests that, similar to the Chaman, Ghazaband and other large faults, the faults inside the microblock also play an important role in adjusting for the collision stress between India and Europe.
Active tectonics in an area includes ongoing or recent geologic events. This paper investigates the tectonic influence on the subsidence, uplift and tilt of western Saurashtra through morphotectonic analysis of ten watersheds along with characteristics of relief and drainage orientation. Watersheds 7–9 to the north (N) are tectonically active, which can be linked with the North Kathiawar Fault System (NKFS) and followed by watersheds 6, 10, 1, 4 and 5. Stream-length gradient index and sinuosity index indicate the effect of tectonic events along the master streams in watersheds 6–9. Higher R2 values of the linear curve fit for watershed 7 indicate its master stream is much more tectonically active than the others. The R2 curve fitting model and earthquake magnitude/depth analysis confirm the region to be active. The reactivation of the NKFS most likely led to the vertical movement of western Saurashtra.
Seasonal variations and common mode errors affect the precision of the Global Positioning System (GPS) time series. In this paper, we explore to improve the precision of coordinate time series, thereby providing a better detection of weak or transient deformation signals, particularly co-seismic signals. Based on 97 GPS stations, including the campaign and continuous GPS stations in Nepal and southern Tibet, we first consider seasonal variations and common errors, then obtain co-seismic deformation of the 2015 Gorkha earthquake in Nepal and southern Tibet. Our co-seismic rupture model is characterized by a shallow ramp and a deeper detachment fault, in agreement with the relocated aftershock sequence. Our results indicate that the earthquake rupture is mainly distributed in the upper-crustal fault, and the maximum slip is up to 8.0 m at ∼15.0 km depth located in the approximate-80 km east of the epicenter. The average slip is more than 5 m, and the total modelled magnitude is MW7.84, consistent with the observed seismic moment. Our rupture model for the 2015 Gorkha earthquake suggests that the rupture zone is not only in the upper crustal Main Himalayan Thrust (MHT), but also spreads to the northern segment of the MHT.
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：