Estimating the Risk of Paired/Grouped Earthquakes and Strong Aftershocks for the Safety of Rescue Process and Post-Seismic Reconstruction

摘要

Quite a few earthquakes tend to occur in pairs or groups. These paired or grouped earthquakes, as well as strong aftershocks following the main shock, threaten the safety of the rescue process and the on-going post-seismic reconstruction, increasing the seismic disasters and the economic/societal losses. One of the practical problems is whether or not the risk of paired/grouped earthquakes and strong aftershocks can be estimated by considering the physical properties of the preceding earthquake or the main shock. In this paper we reported two approaches to such an estimation based on the focal mechanism and apparent stress, respectively, of the preceding earthquake/main shock. We show that earthquakes with thrust mechanisms are more likely to occur in pairs or groups, while strike-slip earthquakes are more likely to be single. Meanwhile, strike-slip earthquakes with extremely low apparent stress or reduced energy tend to be single. These results are applied to the November 14, 2001, Kunlunshan mountain pass, the Qinghai-Tibet border, China, M_w7.8 earthquake.