Development of a synthetically generated earthquake catalogue towards assessment of probabilistic seismic hazard for Tehran

This paper presents the methodology to develop a synthetically simulated earthquake catalogue for northern Iran. The study area covers the northern boundary of Central Iran Plate, which coincides with the Alborz Mountains. A set of areal seismic sources as well as major active faults and their recurrence relationships is modelled to represent the temporal and spatial distribution of potential earthquakes in this region. Probabilistic sampling of events from various spatial and temporal distribution functions, forming sources of uncertainties, is used to generate synthetic events. Areal seismic sources oriented more towards representation of general and background seismicity, derived from statistical and spatial analyses on historical earthquakes. Recurrence relationships as well as potential maximum magnitudes for seismic sources are estimated from records of historical earthquakes and where available from measured and calculated slip rates from recent GPS surveys in this region. The synthetically generated earthquake catalogue provides a realization of potential earthquakes, each characterized with a defined magnitude, location, focal depth, faulting orientation and recurrence frequency. The catalogue is used for assessment of probabilistic seismic hazard, and the results are presented for a test point in the city of Tehran.