The special geological conditions in the Xiji-Langfu area are the main reason for the anomalous high macroseismic intensity caused by the Tangshan, 1976 earthquake. The area is formed by deep deposits-mainly alluvium sands and clays poorly consolidated and with high water content -that have been trapped by the Xiadian fault. From simulated ground motion we have computed quantities commonly used for engineering purposes like the acceleration maximum amplitude (AMAX) and the total energy of ground motion (W), which is related to the Arias Intensity. The thick low velocity deposits are responsible for the large increment of the values of AMAX and W inside the basin. On the two sides of the Xiadian fault AMAX and W can vary by 200% and 700% respectively, and these variations are quite stable with varying thickness of the sedimentary deposit used in the models. With the existing relationships between acceleration (AMAX) and macroseismic intensity (I) our results can explain the large values of I observed in the Xiji-Langfu area, in connection with the Tangshan earthquake.
In this paper a hybrid method, based on mode summation and finite difference, is used to simulate the ground motion of SH wave in the Xiji‐Langfu area induced by the 1976 Tangshan earthquake. We estimate the acceleration maximum amplitude and total energy of ground motion often used for engineering purposes to quantify seismic hazard. On the two sides of the Xiadian fault the acceleration maximum amplitude and total energy can vary by 200% and 700% respectively. Our results can explain the observed anomalous intensity in the Xiji‐Langfu area induced by the 1976 Tangshan earthquake.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.