Integrated Plate Boundary Observatory Chile - MT Component

Monitoring the dynamic behaviour of an active deep subduction system is focus of the Integrated Plate Boundary Observatory Chile (IPOC), a permanent array of combined geophysical and geodetic stations in Northern Chile. It is operated since 2006 by the GFZ German Research Centre for Geosciences. Magnetotelluric (MT) data has been gathered at nine of a total of nineteen observation sites. The average site spacing is approximately 50 km and the monitoring stations are connected via satellite link to the GFZ in Germany. The objective of the MT part of the observatory is to monitor and analyse electromagnetic data to decipher possible changes in the subsurface electrical resistivity distribution. After elimination of a geomagnetic source field effect which strongly affects the measurements (Brändlein et al., 2012), we examine remaining temporal electromagnetic field variations to investigate possible links with the deep hydraulic system of the subduction zone in the aftermath of the earthquake sequence in 2007 near the town of Tocopilla.

Principal investigator

  • Prof. Dr. Oliver Ritter (GFZ)

Research scientists

  • Dr. Jaime Araya
  • Dr. Dirk Brändlein

Cooperation partners

  • Dr. Gabriel Gonzalez, Universidad Universidad Católica del Norte, Chile, Antofagasta
  • Dr. Guillermo Chong Díaz, Universidad Universidad Católica del Norte, Chile, Antofagasta
  • GFZ sections 1.1, 2.1, 2.4, 3.1 and 4.2
  • IPOC partners

Project duration

  • 2006 - present

Field work

  • 2006 - present

Methods & equipment

  • Three component long period fluxgate magnetometers
  • Non-polarising Ag/AgCl electrodes
  • EDL data logger
  • Continuous recording with a sampling rate of 20Hz
  • Magnetotellurics, Geomagnetic Deep Sounding

Additional information

Publications

  • Araya Vargas, Jaime, Large-scale distribution of fluids in the subduction zone of Northern Chile -constraints from magnetotelluric monitoring, Dissertation, Freie Universität Berlin 14. Juli 2016.
  • Araya, J., Ritter, O., (2016): Source effects in mid-latitude geomagnetic transfer functions. - Geophysical Journal International, 204, 1, p. 606-630, doi.org/10.1093/gji/ggv474.
  • Brändlein, D., 2013, Geo-electromagnetic monitoring of the Andean Subduction Zone in Northern Chile, PhD thesis, Free University Berlin.
  • Brändlein, D., Lühr, H., Ritter, O., 2012, Direct penetration of the interplanetary electric field to low geomagnetic latitudes and its effect on magnetotelluric sounding, Journal of Geophysical Research - Space Physics, doi:10.1029/2012JA018008.
  • Brändlein, D., Ritter, O., 2012, Electrical resistivity of the mantle at the South American subduction system in Northern Chile. Proceedings of the 24th Schmucker-Weidelt-Colloquium for Electromagnetic Depth Research, ISSN: 0946-7467, 22-26.
  • Brändlein, D., Ritter, O., Weckmann, U., 2010, A permanent array of magnetotelluric stations located at the South American subduction zone in Northern Chile. In O. Ritter, & U. Weckmann (Eds.), Proceedings of the 23th Schmucker-Weidelt-Colloquium for Electromagnetic Depth Research, ISSN: 2190-7021, 210-215.

Acknowledgements

This project is funded by GFZ German Research Centre for Geosciences.

Oliver Ritter
Group Leader
Prof. Dr. Oliver Ritter
Near-surface Geophysics
Telegrafenberg
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14473 Potsdam
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