摘要In MS7.0 Lushan earthquake, a large amount of strong ground motion recordings were collected. In this paper, we analyze the recordings carefully. The abnormality of ground motion recordings is identified through a log linear regression. In the station of 51BXD, the PGA value has exceeded 1 g, which is the biggest peak ground acceleration (PGA) value obtained from all recordings in this earthquake. The log linear relation shows the PGA value in this station is abnormally large. As this station is located on the footage of a hill, the topographic amplification factor is explored in order to explain this abnormality. Through 3D numerical modeling using spectral element method with transmitting boundary conditions, the amplification factor is quantized. In this station, the topographic amplification is highly polarized in the direction of East–West which agrees with the empirical recordings. This research result suggests us in future directionality of topographic amplification should be considered in the aseismic design.
Abstract：In MS7.0 Lushan earthquake, a large amount of strong ground motion recordings were collected. In this paper, we analyze the recordings carefully. The abnormality of ground motion recordings is identified through a log linear regression. In the station of 51BXD, the PGA value has exceeded 1 g, which is the biggest peak ground acceleration (PGA) value obtained from all recordings in this earthquake. The log linear relation shows the PGA value in this station is abnormally large. As this station is located on the footage of a hill, the topographic amplification factor is explored in order to explain this abnormality. Through 3D numerical modeling using spectral element method with transmitting boundary conditions, the amplification factor is quantized. In this station, the topographic amplification is highly polarized in the direction of East–West which agrees with the empirical recordings. This research result suggests us in future directionality of topographic amplification should be considered in the aseismic design.
基金资助:the National Basic Research Program of China (2011CB013601), the National Natural Science Foundation of China (91215301, 61203276), and the Special Fund of the Institute of Geophysics, China Earthquake Administration (DQJB12B12)
通讯作者:
Xiaojun Li
E-mail: beerli@vip.sina.com
引用本文:
Zhijun Dai, Xiaojun Li. An explanation of the large PGA value of 2013 MS7.0 Lushan earthquake at 51BXD station through topographic analysis[J]. 《地震学报》英文版, 2013, 26(3-4): 199-205.
Zhijun Dai, Xiaojun Li. An explanation of the large PGA value of 2013 MS7.0 Lushan earthquake at 51BXD station through topographic analysis. Earthquake Science, 2013, 26(3-4): 199-205.
