The microzoznation of Ancient Galata Area (Istanbul)based on microtremor recordings

Microtremor measurement technique in the microzonning studies is an efficiently and easily applicable geophysical method to determine dynamic ground behaviours to enlighten and to control civil settlement parameters. Nakamura?s technique which is based on calculation of horizontal and vertical micro tremor acceleration components, is the most feasible option among the other micro tremor methods in assessing the predominant ground periods, soil amplifications, soil damping as well as estimated other parameters such as effective, overburden thickness and soil classification. In this study, the variations of predominant ground periods, soil amplifications and resonance of buildings in Galata and in its archeologically rich vicinity which have lots of historical places such as Galata tower, mosques, churches, temples, inns, city walls, schools are investigated by conducting short microtremor recordings at 147 measurement locations. In addition to that we also determined ground behaviours of the historical area which is surrounded by antic city walls. It is seen that the dynamic behaviour is weak on Holocene Golden Horn deposits, especially strong on slopes and the hill of founded Galata Tower from obtained results. Keywords: Microzonning, microtremor, soil parameters, ground period, soil amplification