Investigating intermediate-depth seismicity in Northern Chile

In the framework of this project, we illuminate the structure of the descending Nazca plate in Northern Chile with seismological means. Over the last ~10 years, a giant set of seismic waveform data has been collected with the IPOC network and several smaller, temporary deployments (e.g. HART-Pisagua, MEJIPE project). From this dataset, we have already compiled a high-resolution earthquake catalog containing more than 100,000 earthquakes with magnitudes between 2 and 8. A large proportion of these earthquakes does not occur on the plate interface, where the Nazca plate and the South American plate slide past each other, but inside the slab of descending Nazca lithosphere. How these so-called ‘intermediate-depth earthquakes’ are created is currently not known. It is assumed that mineral reactions within the downgoing plate release fluids that were formerly bound in hydrous minerals, which enable earthquake activity.

We now utilize the existing datasets to study the seismogenic processes in greater detail. On the one hand, we use imaging techniques that are aimed at characterizing the downgoing plate in great detail, which can e.g. illuminate the oceanic crust atop the slab. On the other hand, we also study earthquake source parameters and thus aim at investigating the physics of the breaking process at depth.

PIs: Jörn Kummerow (FU Berlin), Serge Shapiro (FU Berlin), Bernd Schurr (sec 4.1)

Postdocs: Christian Sippl (sec 4.1), Wasja Bloch (FU Berlin)

Funding: DFG Project