The Geysir volcanic system in the Haukadalur valley of SW Iceland consists of an eroded basaltic central volcano and rhyolitic lava domes of Pleistocene age. Geysers around the world are named for the Geysir geothermal field, which lies SE of the rhyolitic Laugarfjall lava dome and is one of the most frequently visited geological sites in Iceland. No eruptions are known from the Geysir volcanic system during the Holocene.| Smithsonian Institution | Global Volcanism Program
Ring-shaped Deception Island, at the SW end of the South Shetland Islands, NE of Graham Land Peninsula, was constructed along the axis of the Bransfield Rift spreading center. A narrow passageway named Neptunes Bellows provides an entrance to a natural harbor within the 8.5 x 10 km caldera that was utilized as an Antarctic whaling station. Numerous vents along ring fractures circling the low 14-km-wide island have been reported active for more than 200 years. Maars line the shores of 190-m-de...| Smithsonian Institution | Global Volcanism Program
One of the world's most noted volcanoes, Vesuvius (Vesuvio) forms a dramatic backdrop to the Bay of Naples. The active cone was constructed within a large caldera of the older Monte Somma edifice, 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 ...| Smithsonian Institution | Global Volcanism Program
