Development of an early-warning system for monitoring remote volcanoes

Abstract

Many andesitic volcanoes are quiescent for long time periods: usually (but not always) an increase in seismic activity and in deformation precedes an eruption by a few months or a few days. A UNESCO panel has put forward the concept of an early warning system for monitoring dormant volcanoes in remote regions. Simple seismic or deformation measuring devices can in principle be built for monitoring remote volcanoes. These instruments are composed of two units: 1) a processor that measures the baseline «activity» of the volcano and decides when the activity increases above a certain threshold; 2) a transmitter for long distance communication. For slow parameters like tilt or extensometry, the signal can be transmitted every few minutes or hours. For seismology, signals include a large quantity of data and therefore they are usually not transmitted. The processing unit is not easy to design because a single seismic station can record noises that are very similar to «volcanic events». Average noise level on a given time interval, event detection counters and high amplitude ground motion counters are a simple (but not exhaustive) way to summarize seismic activity. The transmission of data from the field to a monitoring center is feasible by present and future satellite telemetry. We present our attempt to develop an early warning system for remote volcano monitoring with data transmission by satellite.