Abstract

Fractures in the Earth’s crust and their connectivity are of critical important for a number of natural and anthropogenic geological applications, as they can act either as conduits or barriers to the flow of fluids such as water, CO2 or oil. Fractures and their frictional properties control the mechanical strength of rock masses, and therefore the location and timing of earthquakes, and fluid entrapment in large, fractured fault zones plays a central role in controlling fault mechanics and consequent seismicity. Magma ascent and subsequent location of volcanic hotspots is controlled in part by connected fracture systems, and many economically important mineral deposits are a direct result of enhanced fluid flow in the fractured regions surrounding faults, such as gold, copper and lithium. Fractured rock networks host reservoirs of oil, gas and geothermal energy resources, but when empty also provide potential storage locations for anthropogenically produced CO2 . In this talk, I will give an overview of the role of fluids in fault and fracture zones in the earthquake cycle, specifically focussing on processes that occur on much faster timescales than we are typically used to as geologists. This includes fracturing and frictional weakening processes that occur during earthquakes and planetary long runout landslides, as well as fast moving coseismic fluids that move through fracture systems, controlling aftershocks and deposition of economically important minerals.