BRIDGSEISMTIME · BRIDGING THE TIMESCALES IN FAULT-SLIP ACCUMULATION: FROM THE EARTHQUAKE RECORD TO THE GEOLOGICAL RECORD

Natural hazards, earthquakes in particular, can have a significant impact on the economic vitality of European regions. An improved understanding of seismic risk can help minimize the loss of human life and resources during extreme seismic events. This proposal aims to investigate the development of faults in the Earth’s crust and to improve the current understanding of earthquake behavior on timescales ranging from individual earthquakes to millions of years. Faults are breaks in the Earth's crust that grow due to slip caused by earthquakes. However, the slip accumulation on faults during successive earthquakes and the patterns arising from this process are poorly understood, mainly due to the brevity of the available earthquake record. The proposed research will employ an interdisciplinary approach that combines geological and geophysical data, geostatistical tools and numerical models to improve our understanding of earthquake occurrence on faults. The major axes of this approach will involve the acquisition, geostatistical analysis and simulation of fault-slip measured from seismic catalogues, paleoearthquake investigations and surface/subsurface geology. Collectively, the data will span timescales of days to millions of years. The objectives will be accomplished by analyzing and combing the statistics of 1792 slip/time measurements from a global dataset of faults located in 6 fault systems. The dataset will be augmented by new field measurements collected from faults in New Zealand using fault-trenching and outcrop geology. Geostatistical analysis of the fault-slip histories will be performed independently for different timescale-data in order to measure their individual earthquake statistical properties. The results will be subsequently merged using Bayesian statistics into a single stochastic model which will simulate slip histories over a range of timescales. The simulated earthquake statistics will then be tested against real world fault-displacement data.