On 1st April, 23:46:50 UTC, an Mw 8.1 earthquake ruptured offshore northern Chile, near the town of Pisagua northwest of Iquique, followed one day later by a Mw7.6 event, both events in the centre of the Integrated Plate boundary Observatory Chile (IPOC). These earthquakes occurred within a seismic gap left behind by two great earthquakes devastating the northern Chilean and southern Peruvian coast about 140 years ago in 1868 and 1877. The segment inbetween, about 500 km long, was the only one along the Chilean subduction zone that has not ruptured within the last century. The earthquakes were recorded by the IPOC multi-parameter stations plus several additional off-line strong- and weak-motion instruments. A network of GPS monuments covering the onshore region deformed by the earthquake was measured just weeks before the event by GFZ scientists. Taking advantage of the long history of preceding work, presence of the permanent multi-parameter network and excellent knowledge of GFZ scientists of the region, a 20 short-period seismograph network was installed to complement the existing pre- and co-seismic data sets. This campaign was the first case for the „HAzard-Risk-Team (HART)“ initiative of GFZ. Stations operated from mid April 2014, i.e. shortly after the mainshock, to January 2016.