D47 Application of EQ-VO coupling model to the Azores – NVI

The application of EQ-VO coupling models in the Azores depends on good prior knowledge about the prevailing regional strain and stress fields. The focus of the work within the workpackage has been on quantifying regional strain taking place on the San Miguel island on the Azores, aiming in particular for determining the background strain at Furnas and Sete Cidades volcanoes.

GPS measurements on San Miguel island from 1993, 1994, 1997, 2000 and 2002 have been interpreted and used to constrain ongoing deformation processes, for comparision with seismic data. The main conclusion of these studies is that slow deformation on San Miguel island is interpreted as a result of plate tectonic transtension, but not as a result of magmatic movements. The results outline low rates of deformation taking place on the Furnas and Sete Cidades volcanoes. The deliverable is a manuscript submitted to Geophysical Journal International (listed below), currently under review.

Description of plate movements on San Miguel during a relatively quiet period 1993-2002 form the basis for interpretation of future deformation data. In case of crisis situations, collection of new GPS data and comparision with older one, can provide important constraints on the nature of ongoing crisis – of direct relevance for the civil defense authorities.

Application of EQ-VO coupling models in the Azores is still in the beginning stage. The work conducted within this workpackage is instrumental for the success of future studies comparing earthquake and deformation data.

Application of EQ-VO coupling models will continue after the end the Retina project.