Earthquake swarms could indicate eruption near Nisyros, Greece

December 5, 2012 – GREECE – A seismic swarm of 2000 micro-earthquakes near the island of Nisyros since 24 November could indicate a start of a or coming of a volcanic eruption near Nisyros. The quakes are located between the area of Simi Island (Greece) and the Bozburun peninsula of SW of Turkey. Information is still scanty, but seismic signals from this possible eruption are very similar to those recorded from current volcanic eruptions. If an eruption is taking place, it would form a new submarine volcano near Nisyros. No proof has yet been found to prove that an eruption may be taking place. Some sources think the swarm may be tectonic (as the Aegean sea is very seismically active). The Volcano Discovery alert will be kept at Green until further evidence is found. The island has a 3 kilometers (1.9 mi) to 4 kilometers (2.5 mi) wide caldera, and was constructed within the past 150,000 years, with 3 separate eruptive stages, ranging from explosive and effusive andesitic eruptions to effusive and extrusive dacitic and rhyolitic activity. Its coasts are generally rocky or pebbled, but there are also a few sandy beaches (mainly in the northeastern part). The volcano is currently active (but not erupting), and fumaroles are found at the craters. It has had four historical eruptions, all of which had a VEI of 2. Almost all of its eruptions involved phreatic activity. The latest eruptive activity was a steam explosion in 1888, after small ash eruptions in 1871 and 1873 and earthquakes are not infrequent. A period of seismic unrest in 1996–1997 led an international team of scientist to initiate monitoring of the volcanic unrest in the European Union sponsored Geowarn project. The entire volcanic complex includes the seafloor between Nisyros and Kos, the island of Gyali, and a part of Kos Island. –Volcano Discovery, Wikipedia