Fig. 1

Observations and seismicity maps of northwestern part of Sumatran islands. a AGNeSS observation map corresponding to rectangle in b. Red and blue squares denote using campaign and continuous GNSS observations, respectively. White squares represent locations that did not use GNSS sites of AGNeSS. Seismicity map is based on BMKG (Agency for Meteorology, Climatology and Geophysics) database (lower detection limit is approximately \(M_{\mathrm{w}}\) 4.5). b Co-seismic offsets resulting from the April 11, 2012 earthquake derived from AGNeSS (blue arrows) and two previous studies (gray arrows) (Yadav et al. 2013; Hill et al. 2015). Red lines denote GSF surface trace. Circles denote seismicity from January 2012 to August 2013. Seismicity map is based on USGS database. c Time series of displacement at ACEH GNSS site