Tuesday, 29 July 2014

Volcanos

Roundup of Global Volcanic Activity

Zhupanovsky (Kamchatka, Russia): Intermittent eruptions continue. New ash emissions occurred yesterday from the volcano. VAAC Tokyo spotted an ash plume at estimated 28,000 ft (8 km) altitude drifting north on satellite imagery.

Nishino-shima (Volcano Islands): Activity at the growing island continues, perhaps even with increased intensity, judging from the recent pictures obtained by the Japanese Coast Guard on 23 July: They show active lava flows reaching the sea and enlarging the island continuously, most notably towards the east, where a stretch of new land up to 250 m wide was added during only 1 month!

Karangetang (Siau Island, Sangihe Islands, Indonesia): An comparably small eruption occurred last week at the volcano. Incandescent lava avalanches were reported to descend from the summit lava dome to the SE, towards the area of Batu Awang, during 19-21 July. It seems to have been a short-lived and relatively small event that did not form the feared pyroclastic flows (which Karangetang is notorious for): avalanches of gas-rich fresh lava that detaches from the dome and/or lava flows and turns into devastating hot turbulent flows that can reach many kilometers distance.

Ibu (Halmahera, Indonesia): New thermal signals have been detected recently coming from the northern rim of the volcano's summit crater, suggesting that the volcano has entered a phase of increased activity. The rarely visited remote Ibu volcano has been in more or less continuous eruption since 1998, slowly growing a new lava dome as well as producing strombolian to vulcanian-type explosions, with significant variations in intensity. The new thermal signals, in the same area where glowing rockfalls had been reported last year, probably indicate that the (continued) lava extrusion has increased recently.

Dukono (Halmahera): Activity at the volcano continues to be elevated. VAAC Darwin frequently spots ash plumes from relatively strong strombolian to vulcanian activity.

Kilauea (Hawai'i): A piece of the crater walls of the Halema'uma'u lava lake collapsed on 23 July and triggered a small explosive eruption. Liquid spatter was ejected to the outer perimeter of the pit crater (including webcam position and the closed observation area) and an ash plume was generated. The reason for the event was a sudden disturbance of the gas influx and release equilibrium of the lava lake induced by the rockfall, triggering a spontaneous and very strong degassing phase.

Reventador (Ecuador): Activity at the volcano has increased with more frequent small to moderately sized explosions from the growing lava dome in its summit. An explosion on the evening of 26 July generated a pyroclastic flow on the southwestern slope that reached almost 1 km length. Seismic activity reflects frequent explosions and tremor, but visual observations are often not possible due to frequent cloud cover. IGPEN characterizes the activity as "moderate". The volcano's activity at the present does not pose a risk for the closest inhabited areas approx. 8 km away.

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