Journey to the centre of the earthquake; what affects earthquake source properties and radiated wavefields?

Earthquakes have the potential to cause enormous human, structural and economic devastation. The frequency and magnitude of the seismic waves produced are a product of the earthquake source - the fault zone that is slipping - and the path along which the seismic waves travel. Little is known about the seismic source, in particular how the characteristics of a fault zone affect the slip kinematics of an earthquake. In principal both the frictional properties of the fault plus the elastic properties of surrounding rock, which will have been modified by fracture damage, will contribute to the nature of the rupture properties. These properties, such as stress drop and rupture velocity, will dictate the source character of the earthquake (e.g., how energetic the rupture is) and the resultant radiated wavefield. This project will use a combination of laboratory experiments and numerical modelling to understand how the properties of the earthquake source are affected by the country rock surrounding a fault. Simulated spontaneous earthquakes will be produced in the laboratory where key properties of the system can be carefully controlled and measured. The elastic properties of the blocks surrounding the slipping fault will be varied to observe the resultant properties of the rupture (velocity and amplitude). Numerical modelling of the ruptures will be developed so that upscaling of the results can be made to predict the larger-scale behaviour of earthquake ruptures.