Are simulated ground motions an option for earthquake risk engineering?

Synopsis

Synthetic ground motion signals (hereinafter, "ground motions" or "GMs"), simulated at fine grid spacing, represent an attractive option for loss estimation purposes within the catastrophe risk modelling framework. Among stakeholders the general concern is that simulated GMs may not be equivalent to real (e.g., recorded during past earthquakes) records in estimating seismic structural demand, and hence, in estimating the induced damages to structures and losses. To overcome this, the Southern California Earthquake Center (SCEC) has established a Technical Activity Group (TAG) focused on Ground Motion Simulation Validation (GMSV) in order to develop and implement testing/rating methodologies via collaboration between ground motion modellers and engineering users worldwide. Within the GSMV TAG, a significant bulk of research has been produced to validate simulated GMs for past earthquakes using intensity measures (conventional and advanced) and several engineering demand metrics, i.e., elastic and inelastic response spectra, generalized interstory drift and floor accelerations spectra, buildings and bridge inelastic responses and fragilities.

The present talk introduces some the main findings of this ongoing project. In particular, the aim here is to address, on a statistical basis, whether state-of-the-art simulated GMs for historical earthquakes are systematically biased in terms of median Engineering Demand Parameters (EDPs) of various structural systems in comparison with real records. The study also investigates the dispersion (i.e., intra-event variability) and the sources of possible differences in the seismic response to recorded and simulated GMs.

The results from this study highlight the similarities and differences between synthetic and real records. These similarities should provide confidence in using the simulation methodology for earthquake risk engineering applications, while the discrepancies, if statistically significant, help in improving the generation of synthetic records.

About the speaker

Dr Carmine Galasso is a Lecturer in Catastrophe Risk Engineering with a joint appointment in the UCL's Department of Civil, Environmental & Geomatic Engineering and the UCL's Institute for Risk & Disaster Reduction. He is also member of the UCL's EPICentre research group and Degree Programme Director for the MSc in Earthquake Engineering with Disaster Management. Prior to joining UCL, Carmine has worked as a Lecturer in Structural Engineering & Catastrophe Risk Modelling in the School of Civil Engineering and Geosciences at Newcastle University, UK, where he is now Associate Lecturer, as a Catastrophe Risk Modeller in the Catastrophe Risk Engineering group of Applied Insurance Research (AIR) Worldwide, San Francisco, USA, and as an Associate Research Scientist in the Department of Civil and Environmental Engineering at the University of California, Irvine, USA.

Carmine's research focuses on the development and use of probabilistic and statistical tools for modelling and managing risk caused by extreme loads on the built environment, with emphasis on developing new tools for hazard-consistent seismic input assessment, engineering applications of earthquake early warning systems, structural reliability and catastrophe risk engineering for earthquake and flood.

Carmine earned both his MSc in (Civil) Engineering Management (March 2007) and his PhD in Seismic Risk (December 2010) at the University of Naples Federico II, Italy. He has authored over 50 journal and conference papers and he is a Section Editor for the Encyclopaedia of Earthquake Engineering by Springer (Section: Seismic Risk Assessment), Guest Editor for the ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems (Part A: Civil Engineering), Review Editor for Frontiers in Interdisciplinary Climate Studies and Frontiers in Frontiers in Built Environment/Earthquake Engineering Journals, and he is involved in several international research programs dealing with earthquake engineering and catastrophe risk modelling.

Further information

This evening meeting is organised by SECED and chaired by Sean Wilkinson (Newcastle University). Non-members of the society are welcome to attend. Attendance at this meeting is free. Seats are allocated on a first come, first served basis. Tea and biscuits will be served from 5.30pm - 6pm. For further information, please contact Greg James (tel. 020 7665 2229).