A minimal rupture model for earthquakeoccurrence with implications for the multiscaleanalysis of physical parameters from the lab tofault systems

Abstract

An accurate assessment of seismic hazards requires a combination of earthquakephysics and statistical analysis. Because of the limits in the investigation of theseismogenic source and of the short temporal intervals covered by earthquakecatalogs, laboratory experiments have been playing a crucial role in improvingour understanding of earthquake phenomena. However, differences are observedbetween acoustic emissions in the lab and seismicity. One of the most pressingissues concerns the role of mechanical parameters (e.g., fault friction) and howthey affect seismic activity depending on boundary conditions and on the spatialand temporal scales. Here, we propose a model for earthquake occurrence basedon seismological evidence in agreement with fracture mechanics. We show that,although extremely simple, not only it reproduces the fundamental properties ofseismicity like other models, but it can also explain some peculiar phenomenaabout observational and statistical seismology (e.g., low stress drops and the originof characteristic earthquakes) being more coherent with earthquake physics.It also provides hints for multiscale modeling of physical parameters. Static anddynamic friction coefficients are investigated. While the latter is not affected by the spatial scale, static frictional resistance decreases with fault size convergingto the dynamic value.