Evaluation of Site Amplification of Erbaa, Tokat (Turkey)

The study area, Erbaa, is one of the largest towns of Tokat with a population of 47000 in the northern part of Turkey. Erbaa is in North Anatolian Fault Zone (NAFZ) and partly located on the Kelkit river plain, also referred to as the Erbaa basin. After the disastrous 1942 earthquake (Ms=7.2), the settlement area was seriously damaged and moved farther southwards of its old place in 1944. Dynamic properties of Erbaa soils were determined and shear wave velocity profiles were prepared to be used in site response analyses as part of a microzonation study. During this process, empirically-based shear wave velocities were calculated and site-specific formulas were proposed. 1-D equivalent linear site response analyses were performed in accordance with site-specific grid model using ProSHAKE (v.1.12) software. The amplification ratio was calculated on the basis of site amplification method using soil/bedrock ratio to obtain amplification factors (AF) for the study area. Amplification factors from 1-D site response analyses mostly vary within a range of approximately 1.5-2.5 in the study area.