Insights into the seismicity and eruptions of PantellerIa Island and its surroundings (Sicily Channel, Italy)

Abstract

The Istituto Nazionale di Geofsica e Vulcanologia – Osservatorio Etneo INGV-OE)manages a permanent local seismic network in Eastern Sicily, with the aim of monitoring the main tectonic areas (Iblei, Peloritani) and active Sicilian volcanoes (Etna, Vulcano, Stromboli). This network enables locating low magnitude earthquakes and detecting low energy signals that are typical of active volcanic areas (e.g. volcanic tremor, explosion quakes, LP events). Apart from Mt. Etna and the Aeolian islands, another area characterized by active volcanism is the Sicily Channel, with the volcanic edifices of Pantelleria and Linosa islands. The emergence (and subsequent disappearance after about two months) in 1831 of the Ferdinandea island, as well as the Foerstner island in 1891 (about 4 km north of Pantelleria), is the most reliable and recent evidence of volcanism in the Sicily Channel, which is undersea for the most part (Fig. 1). Since there are only a few onshore areas in the Sicily Channel, it is therefore diffcult to instrumentally detect its seismicity with traditional onshore networks, with the exception of locating the foci of high-energy earthquakes, which often have poor azimuthal constraints. Ocean Bottom Seismometers (OBS) are not widely used owing to the high costs of the instruments and their running. Consequently, seismological knowledge of the Sicily Channel, and Pantelleria Island in particular, is still lacking in detail. Moreover, there is no permanent local network on the island, which could provide useful data, particularly on the microseismicity. Between 2006 and 2007, we installed a temporary seismic network on the island of Pantelleria, with the aim of improving the knowledge on the local seismicity, and checking for any similarities with other volcanic areas, such as microseismic events that are typical of a hydrothermal environment(e.g. Fossa of Vulcano). In this paper, we compare the instrumental and historical seismicity, and provide a review on the historical eruptions in the Sicily Channel. Finally, we show the results of the experiment with the mobile seismic network deployed at Pantelleria.