Seismic Microzonation and Earthquake Scenarios for Urban Sustainability
Cancelled
Event details
| Date | 19.01.2016 |
| Hour | 16:15 › 17:15 |
| Speaker | Prof. Dr Atilla Ansal, Ozyegin University, Civil Engineering Department, Istanbul, Turkey |
| Location | |
| Category | Conferences - Seminars |
Seismic microzonation and earthquake loss estimation scenarios are needed for city planning, disaster preparedness, risk reduction and hazard mitigation decisions, and urban rehabilitation actions in earthquake prone areas. Loss estimation due to earthquakes in an urban environment is a very complex process that requires detailed building inventories, realistic estimation of earthquake characteristics on the ground surface and comprehensive assessment of building vulnerabilities.
The earthquake hazard is spatially distributed in relation to earthquake sources that need to be assessed based on the regional seismotectonic scale and local site conditions. Mapping the variation in earthquake hazard at an urban scale makes it possible to select zones that may relatively be less affected for the allocation of appropriate land use. Urban development patterns can be oriented toward these zones to minimize possible earthquake damages.
The three principal factors controlling earthquake loss are earthquake source characteristics, site response and structural features. The seismic microzonation maps would indicate the distribution of site response with respect to ground shaking intensity, liquefaction and landslide susceptibility; thus providing an input for urban planning and earthquake mitigation priorities at an urban scale.
A grid system is recommended for dividing the investigation area into cells according to the availability of geological, geophysical and geotechnical data. Site characterizations are performed based on available borings and other relevant information for defining representative soil profiles for each cell with shear wave velocities extending down to the engineering bedrock. 1D site response analyses are conducted to estimate site specific earthquake ground motion characteristics on the ground surface for each representative soil profile. Average of spectral accelerations between 0.1s and 1s periods of elastic acceleration response spectrum are calculated as one of the two parameters representing earthquake shaking intensity on the ground surface. Site specific peak spectral accelerations corresponding to 0.2s period are also calculated as the second microzonation parameter using the empirical amplification relationships proposed by Borcherdt (1994) based on equivalent shear wave velocities for the top 30m of the soil profiles. Superposition of these two parameters is assumed to represent overall effect of site conditions and is adopted as the criteria for the microzonation with respect to ground shaking intensity.
It is also possible to estimate building damage and causalities based on microzonation maps used as an input to earthquake damage scenarios. These estimates may be very approximate and may not always be on the conservative side based on the accuracy of the input data and methods of analyses. However, they can be more realistic when more comprehensive data and more sophisticated analysis methods are implemented. Thus one of the important issues is the estimation of the accuracy and corresponding level of complexity in the analytical studies.
The results obtained using different levels of seismic hazard and site characterisation data will be summarised very briefly to demonstrate the importance of the comprehensive site characterisation as well as the procedures used to estimate site effects for different levels of seismic hazard based on case studies conducted in Istanbul.
Bio : Atilla Ansal received his Diploma Engineering degree in Civil Engineering from Istanbul Technical University in 1969 and his Ph.D. in Geotechnical Engineering from Northwestern University, USA in 1977. He was promoted to Associate Professorship in 1982 and to Professorship in 1988 in Istanbul Technical University. He moved to Kandilli Observatory and Earthquake Research Institute of Bogaziçi University in 2002. Since March 2012 he is professor in the Engineering Faculty of Ozyegin University and Chairman of Civil Engineering Department. He served as visiting professor and researcher in Norway, Portugal, Italy, Japan, USA and UK.
He has been the Secretary General of European Association for Earthquake Engineering during 1994-2014 and President since 2014. He started the publication of Bulletin of Earthquake Engineering in 2002 as the Editor in Kluwer which later became part of Springer. BEE got its first impact factor in 2007 from SCSI, and since then, the impact factor of BEE kept increasing and in 2014 was 1.89 which is the second highest among SCSI Indexed earthquake engineering journals. He is also the Editor in Chief of the book series by Springer on “Geotechnical, Geological and Earthquake Engineering”.
He served as the President of the Turkish Chamber of Civil Engineers between 1998-2000, and of Turkish National Committee on Earthquake Engineering between 2005-2009, Co-chairman of ISSMGE Technical Committee TC4 on “Earthquake Geotechnical Engineering” between 2005-2009, and Core Member of ISSMGE Technical Committee TC 19 on “Preservation of Monuments and Historic Sites” between 2001-2009 and European Technical Committee ETC12 on “Evaluation of Eurocode 8” since 2003.
His main areas of interest are microzonation methodologies, earthquake scenarios, effects of geotechnical factors on earthquake damage, cyclic behaviour of clays and sands, liquefaction, variability of strong ground motion characteristics. He published about 200 articles in conference proceedings, journals, books and as technical reports in English and Turkish.
The earthquake hazard is spatially distributed in relation to earthquake sources that need to be assessed based on the regional seismotectonic scale and local site conditions. Mapping the variation in earthquake hazard at an urban scale makes it possible to select zones that may relatively be less affected for the allocation of appropriate land use. Urban development patterns can be oriented toward these zones to minimize possible earthquake damages.
The three principal factors controlling earthquake loss are earthquake source characteristics, site response and structural features. The seismic microzonation maps would indicate the distribution of site response with respect to ground shaking intensity, liquefaction and landslide susceptibility; thus providing an input for urban planning and earthquake mitigation priorities at an urban scale.
A grid system is recommended for dividing the investigation area into cells according to the availability of geological, geophysical and geotechnical data. Site characterizations are performed based on available borings and other relevant information for defining representative soil profiles for each cell with shear wave velocities extending down to the engineering bedrock. 1D site response analyses are conducted to estimate site specific earthquake ground motion characteristics on the ground surface for each representative soil profile. Average of spectral accelerations between 0.1s and 1s periods of elastic acceleration response spectrum are calculated as one of the two parameters representing earthquake shaking intensity on the ground surface. Site specific peak spectral accelerations corresponding to 0.2s period are also calculated as the second microzonation parameter using the empirical amplification relationships proposed by Borcherdt (1994) based on equivalent shear wave velocities for the top 30m of the soil profiles. Superposition of these two parameters is assumed to represent overall effect of site conditions and is adopted as the criteria for the microzonation with respect to ground shaking intensity.
It is also possible to estimate building damage and causalities based on microzonation maps used as an input to earthquake damage scenarios. These estimates may be very approximate and may not always be on the conservative side based on the accuracy of the input data and methods of analyses. However, they can be more realistic when more comprehensive data and more sophisticated analysis methods are implemented. Thus one of the important issues is the estimation of the accuracy and corresponding level of complexity in the analytical studies.
The results obtained using different levels of seismic hazard and site characterisation data will be summarised very briefly to demonstrate the importance of the comprehensive site characterisation as well as the procedures used to estimate site effects for different levels of seismic hazard based on case studies conducted in Istanbul.
Bio : Atilla Ansal received his Diploma Engineering degree in Civil Engineering from Istanbul Technical University in 1969 and his Ph.D. in Geotechnical Engineering from Northwestern University, USA in 1977. He was promoted to Associate Professorship in 1982 and to Professorship in 1988 in Istanbul Technical University. He moved to Kandilli Observatory and Earthquake Research Institute of Bogaziçi University in 2002. Since March 2012 he is professor in the Engineering Faculty of Ozyegin University and Chairman of Civil Engineering Department. He served as visiting professor and researcher in Norway, Portugal, Italy, Japan, USA and UK.
He has been the Secretary General of European Association for Earthquake Engineering during 1994-2014 and President since 2014. He started the publication of Bulletin of Earthquake Engineering in 2002 as the Editor in Kluwer which later became part of Springer. BEE got its first impact factor in 2007 from SCSI, and since then, the impact factor of BEE kept increasing and in 2014 was 1.89 which is the second highest among SCSI Indexed earthquake engineering journals. He is also the Editor in Chief of the book series by Springer on “Geotechnical, Geological and Earthquake Engineering”.
He served as the President of the Turkish Chamber of Civil Engineers between 1998-2000, and of Turkish National Committee on Earthquake Engineering between 2005-2009, Co-chairman of ISSMGE Technical Committee TC4 on “Earthquake Geotechnical Engineering” between 2005-2009, and Core Member of ISSMGE Technical Committee TC 19 on “Preservation of Monuments and Historic Sites” between 2001-2009 and European Technical Committee ETC12 on “Evaluation of Eurocode 8” since 2003.
His main areas of interest are microzonation methodologies, earthquake scenarios, effects of geotechnical factors on earthquake damage, cyclic behaviour of clays and sands, liquefaction, variability of strong ground motion characteristics. He published about 200 articles in conference proceedings, journals, books and as technical reports in English and Turkish.
Practical information
- General public
- Free
Organizer
- Prof. Dr Katrin Beyer
Contact
- Prof. Dr Katrin Beyer