An overview of geotechnical aspects of the Cay-Eber (Turkey) earthquake

The Cay-Eber earthquake (M-d = 6.0) occurred in the Afyon province in the western part of Turkey on 3 February 2002 and resulted in the loss of 42 lives and damage to buildings in the settlements particularly close to the epicenter. In this study, characteristics of the main shock and its geotechnical aspects such as local site conditions and their effects, liquefaction phenomena and natural slope failures are evaluated. The causative fault is a normal fault with a slight left-lateral component and produced very short surface ruptures due to the presence of top soft and thick alluvial sequence filled the earthquake-affected basin. Horizontal acceleration-time histories and collapse direction of various buildings show a good agreement and indicate directivity effect. The earthquake caused soil liquefaction and limited rock falls. The presence of fine-grained and low permeability topsoil layers in the alluvial sequence prevented a widespread liquefaction and associated ground deformations. Based on the back analysis of liquefaction data and the results of cyclic triaxial testing, values of peak horizontal ground acceleration to initiate liquefaction are inferred. In addition, for selected sites, the assessments based on the soil amplification factors estimated from equivalent shear wave velocities and available microtremor data, and acceleration response spectra revealed that the resonance phenomena was one of the contributing factors in the damage sustained by some buildings. (C) 2004 Elsevier B.V. All rights reserved