Electrical Resistivity Time Evolution of Volcanic Islands: Gran Canaria, Tenerife and La Palma Islands (Spain)

Abstract

The Canary Islands are an archipelago of volcanic origin located off northwest Africa, that comprises seven major islands. Among them Gran Canaria, Tenerife and La Palma. The Canary archipelago is volcanically active. The three islands display signs of Holocene volcanism and Tenerife and La Palma have had historical eruptions in the last 500 years. The last onshore eruption occurred on La Palma in 1971. The age of the islands spans from the 14.7 Ma of the older Gran Canarias islands, 11.7 Ma for Tenerife to 1.7 of La Palma. Electrical resistivity is a parameter that can be used to determine the structure and the processes that have occurred in volcanic islands. In this work we will present the 3D electrical resistivity models of the Gran Canaria, Tenerife an La Palma islands that have been obtained from the 3D inversion of magnetotelluric data acquired at the three islands in the last years. In the three islands a low resistivity structure is found at depth although the geological interpretation of this structure differs among the islands. Some of the differences of the observed electrical resistivity structures present in the three islands can be associated to the time evolution and the difference of ages among the three islands.