Fig. 1
![Fig. 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs40623-020-01197-z/MediaObjects/40623_2020_1197_Fig1_HTML.png)
Map of the location of Nevado del Ruiz volcano (NRV). a Monitoring network at NRV. The square boxes at three infrasound stations show the alignments of two infrasound sensors (a Chaparral 60Vx sensor at ‘C’ and a Hakusan SI104 sensor at ‘H’). The distances of the stations from the NRV crater are 4.2 km (ACOLM), 5.3 km (ACINM), and 6.0 km (ACRUM). b Location of Nevado del Tolima Volcano (NTV) close to NRV. The image sources are RapidEye Satellite image in 2010 for a, and Google Earth (Landsat/Copernicus with copyrights of Maxar Technologies and CNES/Airbus) for b