The study of many large earthquakes in recent years (e.g., Satriano et al. 2014; Grandin et al., 2015; Vallée and Satriano, 2014) has demonstrated that, when looking at the rupture process from its high-frequency (HF) radiation, higher complexity emerges. In particular, HF radiation is not directly associated with large fault slip but rather occurs at the border of the large slip areas, possibly within zones of abrupt changes of rupture velocity or slip rate.
These discontinuities can be, in turn, associated with fault segmentation and spatial heterogeneities of frictional properties, fracture energy or stress drop, as expected from theoretical studies (e.g., Spudich and Frazer, 1984; Gabriel et al., 2013).
An important issue is whether the current imaging methods are able to accurately reconstruct the rupture process on the fault or whether they are rather sensitive to specific areas, depending on the resolution and on the relative position of the receiver array with respect to the source.
The objective of this project is to investigate into detail the variability of the earthquake rupture process, associated with the spatio-temporal heterogeneities of mechanical and dynamic properties in the fault zone.
Rupture complexity influences the way seismic energy is radiated and, in particular, the level and variability of high-frequency seismic waves, which are responsible for strong ground motion. This overall objective will be pursued through the use and further development of high-resolution tools to image in space and time the rupture process and through the study of synthetic source models.