Effects of static stress triggering of the strongest earthquakes along the Bengco—southeastern Piedmont of Nyainqentanglha mountain fault zone, Tibet

Abstract

In this paper, we calculate the Coulomb stress changes triggered by the four strongest earthquakes (M ≥ 6.3) occurred along the Bengco—southeastern piedmont of Nyainqentanglha mountain fault zone in 1411 (M8.0), in 1951 (7.7), in 1952 (M7.4), and 2008 (M6.3). We demonstrate that each strong earthquake occurred in the area where Coulomb stress had been increased (0.018~1.353 bar) by the prior major earthquakes. For example, the Coulomb stress of M7.7 earthquake in 1951 increased by 0.874 bar by the M8.0 earthquake in 1411. The Coulomb stress of M7.4 earthquake in 1952 increased by 1.353 bar by the M7.7 earthquake in 1951. However, the Coulomb stress of M6.3 earthquake in 2008 increased only by 0.018 bar by the M7.4 earthquake in 1952. The 1411, 1951, and 1952 prior strong earthquakes brought cumulative Coulomb stress triggering effects on the Nimu segment of the southeastern piedmont fault of Nyainqentanglha mountain, which is related with the occurrence of the M6.3 earthquake in 2008. The result shows that all of the strong earthquakes on the Bengco—southeastern piedmont of Nyainqentanglha mountain fault zone since 1411 were triggered by a series of prior strong earthquakes and tectonic stress loading.