Multi-disciplinary Monitoring of the 2014 Eruption of Fogo Volcano, Cape Verde

Abstract:

The Fogo volcano, located in the Cape Verde Archipelago (offshore Western Africa), is a complete stratovolcano system. It is the most recent expression of the Cape Verde hotspot, that has formed the archipelago. The summit reaches ~2830m above sea level, and raises 1100m above Chã das Caldeiras, an almost flat circular area.

The last eruption of Fogo started on November 23, 2014 (~10:00UTC), after 19 years of inactivity. C4G, a distributed research infrastructure created in 2014 in the framework of the Portuguese Roadmap for Strategic Research Infrastructures, collaborated immediately with INMG, the Cape Verdean Meteorological and Geophysical Institut with the goal of complementing the permanent geophysical monitoring network in operation on Fogo island. The INMG permanent network is composed of seven seismographic stations and three tiltmeter stations, with real-time data transmitted.

On the basis of increased pre-event activity (which started in October 2014), INMG issued a formal alert of an impending eruption to the Civil Protection Agency, about 24 hours before the onset of the eruption. Although the eruption caused no casualties or personal injuries due to the warnings issued, the lava expelled by the eruption (which last until the end of January) destroyed the two main villages in the caldera (~1000 inhabitants) and covered vast areas of agricultural land, causing very large economic losses and an uncertain future of the local populations.

The C4G team installed a network of seven GNSS receivers and nine seismometers, distributed by the entire island. The data collection started on 28^th November 2014, and continued until the end of January 2015. The mission also included a new detailed gravimetric survey of the island, the acquisition of geological samples, and the analysis of the air quality during the eruption.

We present here a detailed description of the monitoring efforts carried out during the eruption as well as initial results of the analysis of the data collected.

This monitoring effort carried out at the request and in collaboration with INMG, was made possible by an emergency financial support provided by Fundação para a Ciência e Tecnologia, Portugal.