areal exceedance of ground motion as a characteristic of multiple site seismic hazard: sensitivity analysis

Probabilistic seismic hazard assessment (psha) is widely used in earthquake engineering practice and seismic risk management. however, the results of classical point-wise psha contain no information about simultaneous ground motionsduring one earthquake at different sites located within a defined area. such multiple-site estimations are very useful for assessment of damage and corresponding losses in densely populated areas and for analysis of lifeline performance. recently the standard metric for hazard – exceedance rate of a given ground motion level at a particular site – is appropriate andwidely used for specifications in building codes. however, this metric provides no information about simultaneous ground motions at different sites located within a defined area. the design ground motion (dgm) value may be exceeded within certain fraction of the reference area during particular earthquake. to describe how large may be the exceedance fraction and how frequently the dgm value (or any other ground motion level) may be exceeded within thereference area, wenzel and sokolov (2018) introduced a parameter called fraction of areal exceedance (fae). the parameter specifies the probability that a particular ground motion level will be exceeded at least once in at least the fraction (e.g. percentage from 0% to 100%) of the reference area during considered time period (e.g. 50 years).