Influence of site conditions on ground motion at far field loess sites during strong earthquake

• 作 者: WUZhi-jian[1]WANGLan-min[1]WANGPing[1]CHENTuo[2]SHIHang[1]YANGXiao-peng[3]
• 机 构: Lanzhou Institute of Seismology, China Earthquake Administration, Lanzhou 730000, China
• 出 处: 第八届全国青年岩土力学与工程会议暨青年华人岩土工程论坛
• 发表日期: 2013年期

　　Loess is widely distributed in China and the Loess Plateau is one of the major areas where strong earthquakes often take place.The seismic amplification effects were discovered in the Plateau during the Wenchuan Ms8.0 earthquake and some other strong events.Based on earth tremor observation, borehole exploration and site seismic response analysis, the site effects of topography of Loess Yuan on ground motion were investigated in details.The earth tremor investigation shows that predominant frequencies at the bottom sites of Loess Yuan are greater than those at the top obviously.The sites seismic response analysis shows that the Loess Yuan may amplify peak ground acceleration (PGA) by 1.44-2.0 times.Therefore, site effects of mountains and loess topography on ground motion should be taken account into in seismic design in loess regions.