Seismic spatiotemporal characteristics in the Alpide Himalayan Seismic Belt

摘要

Due to the extremely complex regional geological tectonic movements in the Alpide Himalayan seismic belt with the dense population and rapid economic development, the frequent seismic activity has caused huge concern. In geology, the research on the spatiotemporal characteristics of seismic activity in different areas at different scales has always been valuable to explore the mechanism of seismic activity for further simulation and prediction of the seismic activity. Using the spatial autocorrelation analysis in this study, we analyzed the spatiotemporal dynamic characteristics of seismic activity in the Alpide Himalayan seismic belt. According to the historical earthquake list (from 1973 to 2017), the data are divided into five periods. Compared with the commonality and diversity of the spatiotemporal characteristics of seismic activity in different periods, it shows that: there is a positive spatial autocorrelation in each period, which proves the spatial aggregation of the seismic activity in the Alpide Himalayan seismic belt. Nevertheless, over time, the spatial aggregation distribution is gradually diminishing from 1973 to 2017; From the Local Spatial Autocorrelation analysis, the spatial aggregation characteristics of seismic activity change with time and have a significant differentiation among the regions. According to the comparison of Local Spatial Autocorrelation characteristics in different periods, seismic activities in the Alpide Himalayan seismic belt were consistent with the periodic characteristics. Assuming the alternating seismic calm period and active period, we could notice that it turned from the active period to the calm period around 2008, which is the most recent turning point between the active and calm periods. At last, the spatio-temporal dynamic characteristics of the seismic activity in the Alpide Himalayan seismic belt is not only consistent with the formation mechanism of seismic activity but also represents the spatial disparity of the geological tectonic movements. It is the feasibility and effectiveness to explore the seismic mechanism based on spatio-temporal dynamic characteristics of the seismic activity.