Analysis of liquefaction during Van Earthquake

Abstract

The destructive Van Earthquake that struck eastern Turkey on Sunday, 23 October 2011 caused significant damage in the Southeastern Turkish City of Van. It resulted in the collapse of hundreds of buildings and buried numerous victims under the debris. The earthquake killed and injured thousands of people. More than 11,000 buildings sustained various degrees of damage, including more than 6,000 that were rendered uninhabitable, resulting in around 60,000 people being homeless. The moment magnitude of the Van earthquake, Mw = 7.2 (USGS), its epicenter was about 16 kilometers north-northeast of the city of Van, and the focal depth was estimated to be 7.2 km. This study focuses on the seismic liquefactions occurred in Ercis Plain, where Irsat and Zilan streams are discharged to Lake Van. The liquefaction potential in this area was studied using various analytical methods. The assessment of liquefaction triggering and estimation of seismic induced settlement and lateral spreading were performed. The results of site specific ground response analyses showed that the ground motions were amplified significantly during the earthquake, which resulted in larger Cyclic Stress Ratio (CSR) values relative to those, estimated using simplified methods. The comparison of analytical results with post liquefaction observation indicated that a proper evaluation of CSR results in a realistic estimation of liquefaction triggering and post liquefaction deformations.