Geophysical monitoring of the Purace volcano, Colombia

Abstract

Located in the extreme northwestern part of the Los Coconucos volcanic chain in the Central Cordillera, the Purace is one of Colombia's most active volcanoes. Recent geological studies indicate an eruptive history of mainly explosive behavior which was marked most recently by a minor ash eruption in 1977. Techniques used to forecast the renewal of activity of volcanoes after a long period of quiescence include the monitoring of seismicity and ground deformation near the volcano. As a first approach toward the monitoring of the Purace volcano, Southwest Seismological Observatory (OSSO), located in the city of Cali, set up one seismic station in 1986. Beginning in June 1991, the seismic signals have also been transmitted to the Colombian Geological Survey (INGEOMINAS) at the Volcanological and Seismological Observatory (OVS-UOP), located in the city of Popayan. Two more seismic stations were installed early in 1994 forming a minimum seismic network and a geodetic monitoring program for ground deformation studies was established and conducted by INGEOMINAS.