Unusual eruptions

23. Januar 2002

Summary of «Preliminary report on the eruptive activity occurred at Stromboli volcano on 23 January 2002»

by Sonia Calvari, Massimo Pompilio and Daniele Andronico, posted on VOLCANO LISTSERV; Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Catania (INGV-CT) Piazza Roma 2, 95123 Catania (Italy)

«On 23 January at 20:54 (local time) a major explosion occurred. The noise from the explosion was heard from all the villages on the island, and it was accompanied by ash fallout which lasted several minutes. In the morning of 24 January we have surveyed the summit area of the volcano to verify the dispersal of the erupted products and their nature.

The field survey was carried out in the area of Il Pizzo Sopra la Fossa between the Bastimento and La Fossetta This part of the volcano was covered with ash and blocks. Most of the fallout comprised lithic material up to 60 cm in size, with minor amount of spatter up to 1.7 m in lenght. The greater density of lithics on the ground has been found in a belt about 200 m wide between the craters and Il Pizzo. Fine-grained material covered the crater zone and the NE flank of the volcano up to the village of Stromboli. In the zone of Il Pizzo, where usually many tourists stop to look at the eruptive activity, the fallout material formed an almost continuous carpet.

Fallout of this eruption damaged the webcam of INGV - CT and a geochemical station of GNV, both located near the summit. This episode would have posed serious threath also to people if it had occurred when the summit of the volcano is visited by many tourists.

Our survey also revealed morphological changes at Crater 2, which resulted widened when compared to our previous survey of 20 October 2001. From thermal images recorded on 20 October 2001, Crater 2 showed three hot spots with maximum temperatures of 205°C. Crater 2 diameter is now 26 m, whereas estimation of crater size on October last year suggested a maximum size of 10 m.»