As one of the major components of earthquake risk mitigation studies, seismic microzonation can be defined as the process of estimating response of soil layers under earthquake excitations and thus the variation of earthquake ground motion characteristics on the ground surface. It is possible consider seismic microzonation with respect to ground shaking intensity, liquefaction susceptibility and landslide hazard. In all these three cases, the geotechnical site characterization and assessment of site response during earthquakes is one of the crucial phases of seismic microzonation. In addition, site characterization and assessment of site response is also very essential for earthquake scenario studies and site specific structural design.
During the last decade more accurate and sophisticated in-situ testing techniques are developed to determine the needed characteristics of the soil and rock layers for site response analysis. In parallel with these developments, there have been significant efforts to improve the analytical capabilities for analysing two or three dimensional site response taking into consideration the complex site conditions as well as the nonlinear inelastic behavioural characteristics of the soil layers.
In spite of the increase in testing and analytical capabilities, the data needed to validate the developed approaches were very limited. In order to establish reliable methodologies that would match the current needs for earthquake risk mitigation additional data sets are needed.
During the last decade in Turkey, striking effects related to damage distribution and site conditions were observed in 1992 Erzincan, 1995 Dinar, 1999 Kocaeli and Duzce earthquakes. Significant national and international efforts were spend to analyze and evaluate the factors affecting damage and effects of site conditions. Researchers from KOERI-EED took active part in major portion of these projects.
Faculty members of KOERI-EDD also took active part in Int. Committees (i.e. Technical Committee on Earthquake Geotechnical Engineering of the Int. Society of Soil Mechanics and Geotechnical Engineering and in the preparation of Manual for Zonation on Seismic Geotechnical Hazard) and in various international projects (i.e. Microzonation for Earthquake Risk Mitigation Project financed by Swiss Agency for Development and Cooperation). In addition various national microzonation projects in different towns in Turkey were also conducted by the faculty members of KOERI-EDD.
Ansal, A. Editor (2004) Recent Advances in Earthquake Geotechnical Engineering and Microzonation, Kluwer Academic Publishers, 2004.
Ansal, A., Biro, Y., Erken, A., and Gulerce, U. (2003) “Seismic Microzonation: A Case Study” Chapter 8 in Recent Advances in Earthquake Geotechnical Engineering and Microzonation, Kluwer Academic Publications
Ansal, A., Springman, S., Studer, J., Demirbaş, E., Önalp, A., Erdik, M., Giardini, D., Şeşetyan, K., Demircioğlu, M., Akman, H., Fäh, D., Christen, A., Laue, J., Buchheister, J., Çetin, Ö., Siyahi, B., Fahjan, Y., Gülkan, P., Bakir, S., Lestuzzi, P., Elmas, M., Köksal, D., and Gökçe, O. (2003) Part 2C-Case Studies, Microzonation of Pilot Areas, Adapazarı, Gölcük, İhsaniye and Değimendere, Research Task Group Report, World Institute for Disaster Risk Management project on Microzonation for Earthquake Risk Mitigation
Ansal,A.. & Slejko,D. (guest editors) (2001) Soil Dynamics and Earthquake Engineering, Special Issue on Seismic Risk Maps and Scenarios: Protecting Tools Against Earthquakes, Vol.21, No.5
Ansal, A.. (editor)(2001) Lessons Learned from Recent Strong Earthquakes, Proceedings of Earthquake Geotechnical Engineering Satellite Conference, Turkish Chamber of Civil Engineers, Istanbul Section
Ansal,A.., İyisan,R. & Güllü,H. (2001) “Microtremor Measurements for the Microzonation of Dinar”, Pageoph, Special Issue, Vol.158, N.11
Ansal,A.. & Marcellini, A. (1998) “Variability of source and site factors in seismic microzonation, State-of-the-art report”, Proc. 11th European Conference on Earthquake Engineering, Paris, Balkema, Rotterdam Siyahi,B.G. & Ansal,A.. (1993) Manual for Zonation on Seismic Geotechnical Hazard, TC4 Committee of ISSMFE, Japanese Society of Soil Mechanics and Foundation Engineering, pp.55-57.