Volcano Calendar 2018: We're proud to present our 2018 volcano calendar: 13 different and attractive images of volcanoes, volcanic landscapes and phenomena taken during volcano tours over the past few years.
The Volcano Adventure Guide: Excellent information and background for anyone wishing to visit active volcanoes safely and enjoyably. The book presents guidelines to visiting 42 different volcanoes around the world.
The 1635 m high stratovolcano fo Gamkonora is the highest peak on Halmahera.
It has had shifting shifting eruption centers that have produced an elongated series of summit craters along a N-S trending rift. Young-looking lava flows originate near the cones of Gunung Alon and Popolojo, south of Gamkonora.
Since its first recorded eruption in the 16th century, Gamkonora has typically produced small-to-moderate explosive eruptions. Its largest historical eruption, in 1673, was accompanied by tsunamis that inundated villages and killed many people.
Source: GVP, Smithsonian Institution
PVMBG reported that observers at the Gamkonora observation post in Gamsungi (6 km NW), West Halmahera, reported that during 1 August-3 November diffuse white plumes rose up to 70 m above the crater rim. ...more
RSAM values fluctuated; an increase was detected in October coincident with a period of increased tremor. The Alert Level was lowered to 2 (on a scale of 1-4) on 1 July. Residents and tourists were asked not to venture near the crater within a radius of 1.5 km. (Smithsonian / USGS Weekly Volcanic Activity Report 4-10 November 2015) [less]
Increased earthquake activity has triggered an eruption alert by VSI, who raised the volcano's status to 3 ("Siaga", "warning") out of 4 this morning. Indonesian volcanologists reported that the degassing plume from the summit crater of the volcano has turned dark, which suggests the presence of ash (probably phreatic in origin) since 25 May. ...more
The seismicity has shown significant changes with the appearance of harmonic tremor, low-frequency "tornillo" type-earthquakes (known from Galeras volcano in Colombia to often precede explosions). Volcanic-tectonic quakes (VA-type) related to rock fracturing have increased a lot, suggesting that magma at depth is intruding into new dykes. No ash plumes have been detected on satellite images. The last activity of Gamkonora goes back to January, when it produced some small phreatic explosions. [less]
After last week's intense ash eruptions generating plumes 2-3 km high, Gamkonora volcano has quieted down over the past days. Since July 13, seismicity has decreased sharply and no new larger ash eruptions have occurred since then.The Indonesian Volcanological Survey has lowered the alert level and many villagers who had been evacuated from the slopes of the volcano have returned home.
Etna's steam rings: A collection of fantastic vortex rings ("smoke rings") we observed recently on Etna.
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