Study on applicability and its limit of microtremor H/V method

本研究利用日本近年来建立的KiK-net、K-net和大比平原强震观测网的地震观测资料，对微震H/V方法的适用性进行了检验。我们观测了221个基岩S波速度大于1500m/ S的地表微震，并将微震的H/V谱比与地震资料进行了比较。作为审查的结果，澄清了以下几点。在微颤H/V中，一个明显的主峰出现的频率很高。微震H/V谱比不仅与地表地震记录的H/V谱比非常相似，而且与地表与基岩间地震运动的若干谱比也非常相似。这说明微震H/V反映了基于地表水平运动和垂直运动的响应特征。在此基础上，尝试提出了一种利用微震H/V与地震观测资料之间的关系推测地表水平入射波响应特征的工程方法。

In this research, we examined the applicability of microtremor H/V method by earthquake observation data recorded at the strong earthquake motion observation networks of KiK-net, K-net and Nobi Plain which have been established in Japan in recent years. We observed the microtremors at ground surface of total 221 sites where the S wave velocity of base rock is more than 1500m/s, and compared the microtremor H/V spectrum ratio with that of earthquake data. As the result of examination, the followings were clarified. A clear predominant peak appears at a high rate in microtremor H/V. The microtremor H/V spectrum ratio is very similar not only to that of earthquake record on the ground surface, but also to several spectrum ratios of earthquake motions between surface and bedrock. This implies the microtremor H/V reflects the response characteristics based on the both of horizontal and vertical motions in the surface layer. Then, we tried to propose an engineering method in presuming the horizontal incident wave response characteristics of surface layer by using the relation between microtremor H/V and earthquake observation data.