Abstract
Generation of caves under pavements in the coastal area often causes serious accidents, however, those caves are not visible in general. Therefore, it is very important to establish an efficient method for the detection of caves under pavements. This paper aims at discussing the detection method of caves by use of microtremor. Microtremor observation was conducted at Sakaisenboku port where caves were generated. From the single point observation record of microtremor, both horizontal component and vertical component of microtremor were analyzed and it was found to be difficult to detect the caves by the single point observation record of microtremor. Next, array observation record of microtremor was analyzed using the spatial autocorrelation method. Phase velocity at the points with cave was found to be larger than that at the points without cave. As the results, maximum array radius for the detection of caves under pavements were found to be 3.6 meter in this study.
