Conditioning criteria based on multiple intensity measures for selecting hazard-consistent aftershock ground motion records

A mainshock earthquake is typically followed by a sequence of aftershocks, normally with a higher probability of occurrence within the first few days after the mainshock event. Quantifying the subsequent damage due to an aftershock event for a given structure that is already at some state of damage due to the mainshock event is an important task in seismic hazard and loss assessment. This task requires a framework to quantify the aftershock hazard in addition to the mainshock hazard that is already well defined. The present study aims to develop such a framework that facilitates the quantification of aftershock hazard given two sequential fault rupture scenarios-an approach that ultimately serves the basis for a hazard-consistent aftershock ground motion selection. To this end, conditioning criteria based on a single, two, and average-of-multiple intensity measures are utilized in order to select hazard-consistent aftershock records from databases comprising both mainshock and aftershock events. The primary outcome of this study is, thus, a stochastic framework that defines the aftershock seismicity of a given site and enables the aftershock ground motion selection for performance-based seismic assessment and design of structures.