Earthquake slip is accompanied by substantial frictional heating which can activate numerous weakening mechanisms by raising the temperature of the fault gouge. Conversely, temperature anomalies observed across faults after large natural earthquakes have been used to infer the level of dynamic friction. Earthquake rupture models of slip on faults in the Groningen gas reservoir (NL) need to assume that frictional strength breaks down with accumulated slip but at present there is little constraint on the dynamic friction, how this might vary across the different lithologies and how it evolves with slip. Constraining both the level of dynamic friction as well as its variation with lithology requires a thorough understanding of the temperature rise that can occur during seismic slip. Here, we propose to investigate the effect of frictional heating on pore fluid pressure and flow to constrain how much heat is available to raise the temperature and cause dynamic weakening. We will use a laboratory-calibrated magnetic geothermometer to measure temperature anomalies both in experimental faults of Slochteren sandstone and of Ten Boer claystone as well as in samples from faults that outcrop in the U.K., as a natural analogue for the faults presently active in the Groningen gas field to constrain frictional heating in small slip events. Combined, these measurements will constrain the evolution of dynamic friction and temperature within fault rocks of the Groningen reservoir for small magnitude induced events.

The imprint of deep-time paleoenvironmental change on biodiversity Dr. L.M. Boschman, Utrecht University New Caledonia, an island in the Pacific Ocean, is a biodiversity hotspot with a unique species composition. It is unclear why. To better understand how biodiversity develops through geological time, I will study the origin of New Caledonian life, and how it adapted to changes in geography, soil, and climate.

Subduction zones drive global plate tectonics, yet their birth is mysterious. After slow initial convergence, subduction zones initiate with a sudden, catastrophic collapse of a plate into the mantle, but the cause of collapse is unknown. My research shows that rocks in the syn-collapse plate contact are colder than they were pre-collapse; thus, I hypothesize that mineral changes resulting from cooling weaken flow behaviour. I will test this with state-of-the-art 2D-and-3D structural imaging of rocks recording various stages of subduction lifetimes. If correct, ‘refrigeration weakening’ explains collapse and self-sustained plate recycling and impacts understanding of the start of Plate Tectonics.

The researcher unravel how changes in motions of tectonic plates may propagate across the planet in plate tectonic chain reactions. To this end, they reconstruct mountain belts from the Mediterranean region to Indonesia, and around the Pacific Ocean, determine the motions of these plates relative to the Earths mantle, and they model the driving forces behind plate motions.

Earthquakes often result in damage to buildings and infrastructure and sometimes loss of human lives. Induced earthquakes due to human activities like gas extraction, are the result of fast slip on powder-filled pre-existing faults in the subsurface due to a rapid breakdown of their strength. The physical mechanisms contributing to the rapid failure remain unclear. In this project we will perform experiments at scales of a single rock grain to millions of grains combined with computer models to investigate these weakening mechanisms. Our results will help to better constrain the hazard of induced earthquakes.