A new concept of volcano activity monitoring: The multi-parameter station at Galeras volcano (Colombia)

D. Seidl1, D. Bannert, B. Buttkus, E. Faber, S. Greinwald, D. Gomez, R. Torres
1Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Seismologisches Zentralobservatorium, Mozartstr. 57, 91054 Erlangen, Germany.
Tel. : +49-9131-810400, Fax: +49-9131-8104099

In a new approach to monitor the activity and to understand the physics of active volcanoes, the German Federal Agency for Earth Sciences and Natural Resources (BGR) and the Instituto de Investigaciones en Geociencias, Mineria y Quimica (INGEOMINAS) are setting up a multiparameter station on Galeras volcano near city Pasto (Colombia). Galeras (4270 m) is South America's only IDNDR decade volcano. Seismic observations using broadband sensors with a high dynamic range constitute the backbone of the station. The goal of the multi-year project, however, is to study the long-term correlation of the seismic measurements with observations of other physical (electromagnetic, infrasound, thermographic, geodetic) and chemical (gas emission) signals originating from the volcano. To achieve this goal, several relevant parameters are to be measured at the same time, then telemetred continuously to a central monitoring site. The data are recorded, analysed and archived at the Observatorio Vulcanologico y Sismologico de Pasto, which is operated by INGEOMINAS.

As a first step a permanent network of seismic broadband stations and an accelerometer with 24-bit digitizers and digital telemetry using FreeWave spread spectrum radios were installed in July 1997. In addition, other components of the multiparameter station were tested. Using a new and unique instrumental set-up the chemical composition of the exhalation from several fumaroles and the electrical field associated with the volcano were measured. In addition, the temperature field in the active crater was imaged using an infrared thermal scanner mounted in a helicopter.