Anatomy of a Subduction Zone from Ocean Mantle to Crust: Seismicity and Seismic Structure in Northern Chile

Term:
Jan 01, 2015 — Dec 31, 2018

We investigate subduction-related seismic structures, including the fine-scale structure of the megathrust shear zone and underlying oceanic plate, and of earthquake sources in the northern Chile forearc by employing a suite of innovative methods of seismicity processing, imaging and interpretation. We will exploit the specific situation, where an extraordinarily high rate of seismicity has been recorded for almost ten years on a large number of seismic stations, including the permanent IPOC network (http://www.ipoc-network.org/welcome-to-ipoc) and several temporary networks. Northern Chile, in particular the recently installed MEJIPE network on the Mejillones peninsula, also offers a rare chance to monitor at least a part of the seismogenic zone onshore. We therefore expect to image the structural and seismic architecture of this subduction zone at highest possible resolution.

An important component of the project will be the detailed study of seismicity and related physical processes in the deepest, upper ocean mantle layer of the newly confirmed shallow triple seismic zone in northern Chile. Eventually this will contribute to advance the understanding of intermediate depth earthquakes in general.

Directors:

Dr. Jörn Kummerow

Dr. Bernd Schurr (GFZ Potsdam)

Prof. Dr. Serge A. Shapiro

Staff:

Dr. Wasja Bloch (GFZ Potsdam)

Project Partner:

Prof. Dr. Pablo Salazar (Universidad Catolica del Norte, Chile)

Funding:

DFG Project (2015-2018)

Publications:

Bloch, W., J. Kummerow, P. Salazar, P. Wigger, and S. A. Shapiro (2014), High-resolution image of the North Chilean subduction zone: seismicity, reflectivity and fluids, Geophysical Journal International, 197(3), 1744-1749, doi.org/10.1093/gji/ggu084

Salazar, P., J. Kummerow, P. Wigger, S. Shapiro, and G. Asch (2017), State of stress and crustal fluid migration related to west-dipping structures in the slab-forearc system in the northern Chilean subduction zone, Geophysical Journal International, 208(3), 1403-1413, doi.org/10.1093/gji/ggw463

Schmelzbach, C., J. Kummerow, P. Wigger, A. Reshetnikov, P. Salazar, S. A. Shapiro (2016), Microseismic reflection imaging of the Central Andean crust. Geophysical Journal International, 204(2), Pages 1396-1404, doi.org/10.1093/gji/ggv530

Sippl, C., B. Schurr, G. Asch, and J. Kummerow (2018), Seismicity structure of the Northern Chile forearc from >100,000 double‐difference relocated hypocenters. Journal of Geophysical Research,123, doi.org/10.1002/2017JB015384

Bloch, W., B. Schurr, J. Kummerow, P. Salazar, and S. A. Shapiro (2018), From Slab Coupling to Slab Pull: Stress Segmentation in the Subducting Nazca Plate. Geophysical Research Letters, doi.org/10.1029/2018GL078793