(A) The topography of study area with main tectonic faults indicated (black dotted lines). Yellow diamonds depict seismic stations used in this study; black line indicates profiles used for showing the main results; red dotted line highlights the high-resolved area for which resulting maps are presented; solid black lines highlight major volcanic complexes in the area. The inset shows the location of study area (red dot); red triangles depict active volcanoes. NRV is Nevado del Ruiz Volcano. (B) Numbers of events per month and cumulative value for dataset used in this study. Areas of different colors highlight the time periods used for data selections. This picture is produced using Surfer 12, Golden Software.