December 30, 2002 Tsunami: Stromboli Island, Italy

Two large slides with a total volume about 17 million cubic meters occurred on December 30. It generated a tsunami that "caused severe destruction in the [Stromboli] island, produced some damage in the Aeolian archipelago, and was observed in several coastal places in the south-Tyrrhenian sea" (ref #2439).

On 30 December at 1315 and 1322 two landslides suddenly formed along the Sciara del Fuoco. As they traveled down the volcano's flank they produced wet, fine ashfall (less than 0.1 mm in size) on the island's SE side. The first landslide had a volume of about 600,000 m3, the second about 5,000,000 m3, and they both reached the sea. Upon contact with the sea the landslides produced two tsunamis with waves that were several meters high. The tsunamis injured few people, and damaged buildings and boats in the villages of Stromboli and Ginostra. Large waves were reported as far away as the town of Milazzo, on Sicily's N coast, 60 km S of Stromboli... According to several news articles, volcanic activity at Stromboli on 30 December caused a landslide, which entered the sea and generated a tsunami. The articles stated that in the small village of Ginostra, waves injured six people, and damaged homes and boats. Residents and tourists were evacuated to nearby Sicily. (ref #2432)

During the last months of 2002 Stromboli was dominated by an intense explosive activity that lasted till December 28. On that day Stromboli started a new effusive phase that compromised the stability of the Sciara del Fuoco flank leading to the landslides of December 30. It has been ascertained that two different landslides occurred in that day. The first one occurred at 13:15 and it was mainly a submarine one, whereas the second one, occurred 7-8 min later and produced a subaerial scar on the Sciara del Fuoco at a height of 500 m a.s.l., for a volume of about 7-8 million cubic meters. The mass moved by the first landslide was much greater than the sub-aerial one, and bathymetric surveys revealed that the total volume of the material moved by the two slides was about 20 million cubic meters. According to Tinti both landslides produced tsunami waves: the first event was characterized by a first negative sea movement, while the second produced a positive wave. The submarine slide caused a sea level lowering of about 10-15 m at the foot of the Sciara, immediately propagating in both directions, northward towards Piscità and southward towards Ginostra. A destructive tsunami, starting with an initial slow withdrawal, violently invested the northern coasts of the island with three-four big waves. It has been ascertained that within a few minutes the water invaded Ficogrande beach, and attacked Punta Lena and Scari producing severe damage. The second tsunami was generated around 13:22 by a subaerial mass failure. Only a few people were able to distinguish the arrival of the second tsunami and to recognize the positive leading wave, while most considered it as the continuation of the first. Several field surveys were undertaken soon after the event both in the near and far-field. The strongest tsunami effects were observed at Stromboli. In the beach called Spiaggia Longa (north-eastern coast) the highest value of runup (10.90 m) was measured. At Piscità the buildings located near the shore were seriously damaged. (ref #4139)

The total volume of the involved material was about 20,000,000 m3, the largest contribution coming from the submarine displacement [...] Low season visitor numbers to the island determined that only minor injuries were reported; otherwise, the victim toll might have been much higher. (ref #4395)