An eroded central cone was constructed during the late Pleistocene, along with an isolated cone near the NW coast. Two Holocene cones were built within the crater of the central cone. The westernmost forms the 956-m high point of the island and is the source of lava flows that flooded the crater floor and descended to the coast. This crater may have formed during a violent eruption in 1846. The only other known historical eruption produced weak explosions in 1957.
Fumarolic activity continues in the eastern crater and in the saddle between the two summit cones.
Click on the index link or scroll down to read the reports. All information contained in these reports is preliminary and subject to change. Fumarolic areas in the crater Four groups of fumaroles were observed in a crater, breached to the SE, during a 14 January overflight.