Weekly Volcano Watch: 9 April 2009

Volcanic Activity Report: 1 April – 7 April 2009

Source: SI / USGS Weekly Volcanic Activity Report

New activity/unrest:

• Ebeko, Paramushir Island (Kuril Island chain, Russia)
• Krakatau, Indonesia
• Llaima, Central Chile
• Nyamuragira, Democratic Republic of Congo
• Nyiragongo, Democratic Republic of Congo
• Pacaya, Guatemala
• Redoubt, Southwestern Alaska

VoW: Vesuvius

An aerial photo of Vesuvius. Source: solarnavigator. Image may be subject to copyright.

Country: Italy
Region: Campania
Volcano Type: Somma volcano
Last Known Eruption: 1944
Summit Elevation: 1281 m (4,203 feet)
Latitude: 40.821°N 40°49’17″N
Longitude: 14.426°E 14°25’34″E

One of the world’s most noted volcanoes, Vesuvius (Vesuvio) forms a dramatic backdrop to the Bay of Naples. The historically active cone of Vesuvius was constructed within a large caldera of the ancestral Monte Somma volcano, thought to have formed incrementally beginning about 17,000 years ago. The Monte Somma caldera wall has channeled lava flows and pyroclastic flows primarily to the south and west. Eight major explosive eruptions have taken place in the last 17,000 years, often accompanied by large pyroclastic flows and surges, such as during the well-known 79 AD Pompeii eruption. Intermittent eruptions since 79 AD were followed by a period of frequent long-term explosive and effusive eruptions beginning in 1631 and lasting until 1944. The 1631 eruption was the largest since 79 AD and produced devastating pyroclastic flows that reached as far as the coast and caused great destruction. Many towns are located on the volcano’s flanks, and several million people live within areas potentially affected by eruptions of Vesuvius. Photo by Dan Dzurisin, 1983 (U.S. Geological Survey). Caption: GVP.

[Note: A somma volcano is a volcanic caldera in which a new cone  has grown. The name comes from Mount Somma, a stratovolcano that hosts the cone of Mount Vesuvius. Other examples of somma  include volcanoes on  Kamchatka Peninsula (Russia) and the Kuril Islands that extend from Kamchatka to the island of  Hokkaido, Japan.]

Index of monthly reports (GVP)

• 06/1996 (BGVN 21:06) Seismicity during 1995-96 is the highest in the past 50 years
• 08/1996 (BGVN 21:08) Ongoing sub-crater seismic activity
• 04/1997 (BGVN 22:04) Low seismicity prevails after March-May 1996 earthquake swarm
• 10/1999 (BGVN 24:10) 9 October seismic swarm includes an M ~ 3.5 event, the largest in 50 years

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Vesuvius Eruption photographed in March 1944. Image: John Reinhardt, USAAF.

FEWW Forecast: There is at least a 0.6 probability that Vesuvius may erupt by August/September 2009.

Ongoing Activity:

• Asama, Honshu (Japan)
• Batu Tara, Komba Island (Indonesia)
• Galeras, Colombia
• Karymsky, Eastern Kamchatka (Russia)
• Kilauea, Hawaii (USA)
• Koryaksky, Eastern Kamchatka
• Popocatépetl, México
• Rabaul, New Britain
• Sakura-jima, Kyushu
• Shiveluch, Central Kamchatka (Russia)
• Soufrière Hills, Montserrat
• Suwanose-jima, Ryukyu Islands (Japan)
• Tungurahua, Ecuador