Volcanos

Roundup of Global Volcanic Activity

Stromboli (Eolian Islands, Italy): Occasional mild strombolian explosions occur from the summit vents. Very weak lava effusion also continues, at least intermittently from the vent at 650 m elevation.

Ontake-san (Honshu): JMA reported that cloud cover often prevented visual observations of Ontakesan during 5-11 November; white plumes rose 200-300 m above the crater rim and drifted NE, E, and SE. The Alert Level remained at 3 (on a scale of 1-5).

Suwanose-jima (Ryukyu Islands): Tokyo VAAC reported a small eruption this morning, producing an ash plume to 6,000 ft (1.8 km) altitude. At least intermittently, the volcano continues to produce strombolian explosions of varying intensity.

Mayon (Luzon Island): During 5-11 November white plumes rose from Mayon's crater and drifted S, SW, WSW, WNW, and NW, sometimes downslope. Weak incandescence from the crater was noted some nights. As many as five volcanic earthquakes were recorded per day. The Alert Level remained at 3 (on a 0-5 scale).

Ibu (Halmahera, Indonesia): When observed during 12-13 Nov, there was frequent mild to moderate explosive activity from at two different vents in the center of the lava dome. No activity was observed at the lava dome itself. The vent to the south is surrounded by a recent-looking cinder cone, about 30 m tall and 60 m wide, and produced likely phreatomagmatic explosions at intervals of 20-30 mintues. These typically seemed to start from a cluster of vents inside the cone's crater, ejecting dense white steam as well as gray ash plumes, sometimes followed by dense black tephra jets reaching 10-20 m in height. Sometimes, the ash plumes collapsed to form small pyroclastic flows running down the western slope of the cone. At night, weak incandescence could be seen and only few glowing blombs were ejected during these eruptions.

Monowai (Kermandec Islands, New Zealand): New Zealand scientists concluded that most likely 3 underwater eruptions occurred during this October at the shallow submarine volcano, one of the most active ones in the Tonga-Kermadec arc. This conclusion was based on both the observation of a pumice raft in the area on 31 Oct and the analysis of so-called T-waves, a particular kind of acoustic waves that propagate well in the ocean and have been found to be typically associated with submarine eruptions from Monovai seamount.

Pavlof (Alaska Peninsula, USA): A new eruption began at the volcano on 12 Nov afternoon about 3:00 pm AKST (00:00 UTC on 13 November). The eruption comes from a vent at the upper northern flank just below the summit and has been characterized by ash emissions to about 9000 feet (2.7 km), lava fountaining and avalanches of rock debris and ash descending the north flank of the volcano. Minor ash emissions were visible in the FAA-operated web camera in Cold Bay beginning around 4:50 pm AKST yesterday (1:50 UTC on 13 November). Observations from ground observers in Cold Bay coincided with a subtle but distinct increase in seismic activity, and the appearance of a thermal signal at the summit of Pavlof evident in satellite images at 5:40 pm AKST (02:40 UTC 13 November). Since these initial reports of activity, seismic activity has continued to increase gradually and the thermal signal at the summit remains evident in satellite data. Cloud cover has obscured the volcano and no new observations on ash emissions are available. However, the level of seismicity suggests that ash emission continues. (AVO)

Santiaguito (Guatemala): Both explosive and effusive activity continue from the Caliente lava dome. The observatory reports weak ash explosions ejecting plumes that rise approx. 500 m. The length of the viscous lava flow to the SE is now more than 3.3 km long and has two active fronts, one inside the Nima1 river bed, the other outside its banks.

Pacaya (Guatemala): It seems new strombolian explosive activity has started around 10-11 November from the Mackenney crater. INSIVUMEH reported in its special bulletin that an increase in gas emissions as well as fine ash expulsions have been observed. Together, they form plumes reaching 3000 m altitude and drifting SW for approx. 7 km. The seismic signal shows elevated activity as well. This could be the beginning of a new episode of strombolian activity, which in turn would slowly start building a new cone inside the Mackenney crater.

Fuego (Guatemala): Explosive activity from the volcano has slowly been increasing over the past 1-2 weeks. Eruptions of moderate size with ash plumes up to more than 1000 m height have become more frequent. Shock waves could be felt in up to 20 km distance and rattled windows and roofs of houses in villages around the volcano.

Reventador (Ecuador): IG reported moderate volcanic activity including explosions, long-period earthquakes, harmonic tremor, and tremor at Reventador during 5-11 November. On 11 November steam plumes with a minor ash content rose 1 km and drifted NW. Cloudy conditions frequently obscured views of the summit.