Project description

What influence do metamorphic reactions have on the short- and long-term deformation behaviour of high-pressure and high-temperature rocks? Can metamorphic reactions trigger deep earthquakes?

We investigate whether and how metamorphic reactions can influence the rheology of rocks in different geological environments. In this project, we focus on the effects of hydration reactions on the rheology of the lower continental crust as well as on the influences of dehydration reactions in subducting oceanic crust that can trigger deep earthquakes and/or slow slip events. To this end, we combine complementary experimental methods with extensive structural and chemical analyses of the experimental samples. 

We try to link the findings in the laboratory with observations in natural rocks. The tangible evidence for the existence of deep earthquakes are pseudotachylites (see picture above). These glass-bearing veins in rocks are quenched frictional or deformational melts and are generally recognised as the result of rapid seismic displacement along fault surfaces. Why we find these structures in rocks of the lower crust and upper mantle is still not understood, as the high temperatures that prevail in the lower crust and upper mantle mean that frictional processes should not play a role in these rocks. By chemically and structurally analysing these earthquake structures, we are trying to better understand why these deep earthquakes could occur. It is often observed that the chemical composition of the pseudotachylites is different from that of the surrounding rock. Therefore, one theory is that chemical reactions in the rock (metamorphic reactions) could trigger these earthquakes. 

Project duration

2019 - 

Funding

Humboldt fellowship (2019-2021)

Cooperation

Ruhr University Bochum

University Potsdam