论文部分内容阅读
大规模流动地震台阵观测已经成为高分辨率深、浅部结构成像的重要手段和发展方向,台基条件和背景噪声是影响流动地震观测质量的关键因素.为了研究地形条件对背景噪声的影响,服务于降噪流动观测技术的发展要求,开展了龙祠地震台毗邻的麦圪岭小山地形对背景噪声的放大影响研究.通过地震观测和开放体系的时域显式波动有限元SH、P-SV波动数值模拟分析,结果表明,(1)不管是把白噪声信号当作SH型地震动,还是当作P-SV型地震动,山顶相对于山洞的传递函数,在频率16—18Hz之间,发现了由于山体地形导致的背景噪声的放大效应,该结果与背景噪声的观测结果相一致;(2)从山顶、山腰、山洞到山脚这4个观测点,数值模拟的震动响应最大值逐渐减小,揭示了地形放大效应,山顶相对于山脚的放大因子约为2.0;(3)场地土层对背景噪声的放大效应显著,甚至远超过地形效应的影响.
Large-scale mobile seismic array observation has become an important method and direction of high-resolution deep and shallow structure imaging, and the base station conditions and background noise are the key factors affecting the quality of mobile seismic observation.In order to study the impact of topography on background noise , To serve the development requirements of noise reduction flow observation technology and to study the amplification effect of background noise on the Meiling ridge hill adjacent to Longci station.Through the observation and open system of time domain explicit wave finite element SH, P The results show that (1) no matter whether the white noise signal is taken as the SH type ground motion or the P-SV type ground motion and the peak as the transfer function of the cave, And found the amplification effect of the background noise caused by the mountain topography. This result is consistent with the background noise observations. (2) From the summit of mountain, mountainside and cave to the foot of mountain, the maximum value of the numerical simulation vibration response Gradually reduced and revealed the effect of topography amplification. The amplification factor at the top of the mountain is about 2.0 with respect to the foot of the mountain. (3) The amplification effect of background soil on the background noise is significant, even far exceeding the topographic effect Impact.