The 7th International Conference on Advances in Civil and Ecological Engineering Research (ACEER 2025)

Abstract: The basic purpose of Seismic Microzonation is to evaluate the seismic hazard on the ground surface with respect to ground shaking intensity. A probabilistic local seismic hazard study is the initial phase to define the probable earthquake characteristics on the rock outcrop. In recent years, with the increase in the computational capabilities, detailed probabilistic site response analyses are being conducted to determine possible site effects and earthquake characteristics on the ground surface to estimate earthquake damages for the existing building stock.
The basic issues are the uncertainties in source characteristics, soil profile, soil properties, and characteristics of the building inventories that would introduce critical uncertainties associated with these analyses. At this stage, the probability distribution of the related earthquake parameters on the ground surface may be determined considering all possible input acceleration time histories, site profiles, and dynamic soil properties. One option, the variability in earthquake source and path effects may be considered using a large number of acceleration records compatible with the site-dependent earthquake hazard. Likewise, a large number of soil profiles may be used to account for the site condition variability. A seismic microzonation methodology is proposed based on the probabilistic assessment of these factors involved in site response analyses. The second important issue in the seismic microzonation procedure is the selection of microzonation parameters. The purpose is mitigation of structural damage, it is possible to adopt earthquake parameters like cumulative average velocity (CAV) or Housner intensity (HI) that was observed to have a better correlation with building damage during past earthquakes. The main approach is to develop a microzonation procedure for ground shaking intensity considering probabilistic values of ground motion parameters. The third issue is the reliability and correctness of the site response analysis procedure. The adopted site response method is updated for frequency and stress dependence to achieve the preferred correctness.

Biography: Dr. Atilla Ansal received his Ph.D. in Geotechnical Engineering from Northwestern University, USA in 1977. He was promoted to full Professorship in 1988 in Istanbul Technical University, moved to Kandilli Observatory and Earthquake Research Institute of Bogaziçi University in 2002. Since March 2012, he is professor in the Civil Engineering Department of Ozyegin University.
He served as the Secretary General of European Association for Earthquake Engineering during 1994-2014 and President during 2014-2018, Vice President during 2018-2022 and currently Honorary Member of EAEE. He also served as Co-Chairman of ISSMFE Technical Committee TC4 on “Earthquake Geotechnical Engineering between 2005 – 2009.
He has been the Editor in Chief of the Bulletin of Earthquake Engineering and the book series on “Geotechnical, Geological and Earthquake Engineering” by Springer since 2002. He worked as visiting scholar in Tokyo University, Japan, in LNEC, Portugal, in University College, UK, University of Napoli, Italy, and USGS Menlo Park, USA.
He served as the President of the Turkish Chamber of Civil Engineers during 1998-2000 and Co-Chairman of the Organizing Committee for the 2014 Second European Conference on Earthquake Engineering and Seismology held in Istanbul.
He was selected for the Prof. Ambraseys Lecture Award by EAEE for the year of 2024, 15th Nonveiller Lecture Award for the year of 2017 by Croatian Geotechnical Society, Zagrep, Croatia, Third Prof.Dr. Rıfat Yarar Lecture Award for 2015 by Chamber of Turkish Civil Engineers and Earthquake Engineering Committee of Turkish Earthquake Foundation, and Third Ord.Prof.Dr. Hamdi Peynircioglu Lecture Award for 1988 by the Turkish National Committee on Soil Mechanics and Foundation Engineering.
His main areas of interest are microzonation methodologies, site response analysis, effects of geotechnical factors on earthquake damage, liquefaction, cyclic behaviour of clays and sands, constitutive soil models. He published large number of papers in conferences and engineering journals.