The largest earthquakes occur at tectonic plate boundaries in subduction zones, known as subduction megathrusts. The subduction megathrust in northern Chile (19°-23°S) has been monitored since 2007 by the Integrated Plate Boundary Observatory Chile (IPOC) network, which includes an array of 11 long-period magnetotelluric (MT) sites to infer changes in deep fluid distribution. Here we present time-series data from 2007-2016, the interval encompassing the precursory and foreshock seismic sequences of the 2007 Mw 7.7 Tocopilla and 2014 Mw 8.1 Iquique earthquakes, an interval that also includes a dozen slow slip events. The time series for this data publication represent a subset of the MT data recorded within the framework of the IPOC project. The dataset comprises 5-component MT data from 5 sites with sampling rate of 8 Hz and 1 Hz. This data publication (10.5880/GIPP-MT.200699.1) encompasses a detailed report in pdf format with a description of the project, information on the experimental setup, data collection, instrumentation used, recording configuration and data quality. The folder structure and content of the data repository are described in detail in Ritter et al. (2019). Time-series data are provided in EMERALD format (Ritter et al., 2015).

The Geophysical Instrument Pool Potsdam (GIPP) provides field instruments for (temporary) seismological studies (both controlled source and earthquake seismology) and for magnetotelluric (electromagnetic) experiments. The GIPP is operated by the GFZ German Research Centre for Geosciences. The instrument facility is open for academic use. Instrument applications are evaluated and ranked by an external steering board. See Haberland and Ritter (2016) and https://www.gfz.de/gipp for more information.