Southern Europe and Turkey lie within the highest seismic risk areas in the world. Understanding the physico-chemical processes controlling earthquake generation is essential in seismic hazard assessment. Destructive earthquakes nucleate at depth (7-15 km), therefore monitoring active faults at the Earth's surface, or interpreting seismic waves, yields only limited information on earthquake mechanics. We propose to investigate earthquake processes by:
1) installing a new world class high velocity rock friction apparatus to perform experiments under deformation conditions typical of earthquakes;
2) studying fossil seismic sources now exhumed at the Earth's surface;
3) analyzing natural and experimental fault rock materials using a novel multidisciplinary approach involving state of the art techniques in microstructural analysis, mineralogy and petrology;
4) producing new theoretical earthquake models calibrated (and tightly constrained) by field observations, mechanical data from rock-friction experiments and analyses of natural and experimental fault rocks.
The integration of such an original and complementary data set shall provide an unprecedented insight into the mechanics of seismic faulting. The proposed study has additional implications for understanding other friction-controlled processes important in Earth sciences and hazard mitigation¬ (e.g., rock landslides). Friction also has broad applications in the industry, including innovative but poorly understood production processes. Our experimental results will help to improve industrial milling techniques and investigate the mechanical-chemical transformations induced during milling.
The scope of the machine is to simulate seismic slip during an earthquake, under ambient conditions approaching as much as possible those of natural faults. Such conditions combine, for example, seismic slip rates (1 m/s) on the fault and and high normal stress due to lithostatic load at seismogenic depth (typically, down to 30 km in the Earth Crust and 20-200 MPa). These conditions represent a new frontier in the field of material studies.
The machine belongs to the class of HVRF "High Velocity Rotary Friction" apparatuses, first proposed and developed by T. Shimamoto, Japan. However, the SHIVA prototype is planned to surpass by and large previous limits on slip-rate, stress and high-speed response to rapid variations.
As such, SHIVA poses several technical challenges and this machine is a prototype with unique, high-tech properties.