Sistema de vigilancia geodésica en las Islas Canarias

Comunicación presntada a la 3ª Asamblea Hispano-Portuguesa de Geodesia y Geofísica = 3ª Assembleia Luso-Espanhola de Geodesia e Geofisica, celebrada en Valencia entre el 4 y el 8 de febrero de 2002.
To define the most suitable volcano monitoring system is a particularly difficu/t task in the absence of recent activity. It must take into account not only the technical optimization of the monitoring systems, but also their economic and scientific profitability. Traditionally, observations of seismic, hydrologic, or fumarolic activity have proven useful. Since volcanic activity almost inevitably produces deformation and gravity changes before, during, between and after the events geodetic techniques are now included, in the light of the lA VCEJ's recommendations regarding routine monitoring. They are proving to be a powerful tool in the monitoring of volcanic activity detecting anomalies somefimes months or weeks before the magma jlow leads to earthquakes or other eruption precursors. Geodetic monitoring thus complements seismic monitoring by extending the study of volcanic phenomena from seconds to years and providing details on the growth of magma bodies within the volcano. Canary Islands, with a population of about 1.8 mil/ion people, are located less than /00 km from the African continent. They were formed on the continental rise and slope as independent structures. Despite being on a passive margin, they are a volcanic archipelago with a long-standing history of volcanic activity that began more than 40 m.y. ago. At least a dozen eruptions occurred on the islands ofLanzarote, Tenerife, and La Palma between /500 and 197 J. Several different types of volcanic manifestations, which follow a time pattern are to be seen on the Canary Islands. This is a typical case in which the volcanic monitoring system must be carefully designed. The system must be efficient, but must also make full use of existing facilities and have acceptable installation and running costs, in line with the current inactivity. In this presentation we described a proposal for the geodetic monitoring system in Canary lslands. This monitoring system has been develoloped with base on experimental results from different research projects and the application of theoretical analysis. This system makes used of terrestrial and space geodetic techniques.