Site-specific issues for strong ground motions during the Kocaeli, Turkey, earthquake of 17 August 1999, as inferred from array observations of microtremors and aftershocks

Abstract

Array observations of microtremors and aftershocks were carried out near the permanent strong-motion observation sites and the damaged areas, after the Kocaeli, Turkey, earthquake of 17 August 1999. The major objectives were to determine S-wave velocity structures at the sites and to understand the site effects on strong motion or damage. Array observation of microtremors is a useful method for determining the S-wave velocity structures in a sedimentary basin, with less practical restriction than the other geotechnical methods. The spatial autocorrelation method (SPAC) was applied to array data of microtremors for determining S-wave velocity structures. The SPAC method generally provides an equivalent result with that of the frequency-wavenumber method, using fewer array sites and a smaller array size.