Thursday 29 September 2016

Volcanos

Roundup of Global Volcanic Activity

Klyuchevskoy | Central Kamchatka (Russia) | 56.056°N, 160.642°E | Elevation 4754 m

KVERT reported that a Strombolian eruption at Klyuchevskoy continued during 16-23 September. Volcanic bombs that were ejected above the summit crater and the cinder cone landed in the Apakhonchich drainage on the E flank. A lava flow traveled down the Apakhonchich drainage and also down the SW flank. Satellite images showed a large and bright daily thermal anomaly at the volcano. During 20-22 September explosions generated ash plumes that rose as high as 7 km (23,000 ft) a.s.l. and drifted 100 km SW, E, and SE. The Aviation Color Code remained at Orange.

Tengger Caldera | Eastern Java (Indonesia) | 7.942°S, 112.95°E | Elevation 2329 m

PVMBG reported that during 1 June-25 September brownish gray plumes from Tengger Caldera's Bromo cone rose as high as 1.2 km above the crater. A sulfur odor was noted at the Bromo observation post, thunderous noises sometimes vibrated the post doors, and occasionally crater incandescence was observed. Seismic activity was dominated by shallow volcanic earthquakes and tremor. The deformation network measured inflation. Based on analyses of satellite images and information from PVMBG, the Darwin VAAC reported that during 22-23 September ash plumes rose to an altitude of 3 km (10,000 ft) a.s.l. (720 m above the crater) and drifted almost 40 km SW. On 26 September the Alert Level was raised to 3 (on a scale of 1-4); residents and visitors were reminded not to approach the crater within a radius of 2.5 km.

Tungurahua | Ecuador | 1.467°S, 78.442°W | Elevation 5023 m

IG reported that Tungurahua's seismic network detected a significant increase in the number of long-period (LP) earthquakes on 12 September and small episodes of tremor beginning on 16 September. A swarm of 24 LP events were detected during 0408-0424 on 18 September. Starting at 1400 on 24 September the number of LP events again increased. Gas emissions were low, and together with the increased seismicity, possibly indicates a blocked conduit. IG noted that a possible large-scale eruption may happen within hours to days. In response, the Secretaría de Gestión de Riesgos (SGR) announced that the Alert Level was raised from Yellow to Orange (the second highest on a 4-color scale) on 26 September.

Turrialba | Costa Rica | 10.025°N, 83.767°W | Elevation 3340 m

OVSICORI-UNA reported that during 21-22 September multiple eruptive episodes at Turrialba generated ash, gas, and steam emissions that generally rose as high as 700 m above the crater and drifted N, NW, W, and SW. Ashfall and a sulfur odor were reported in some areas of Valle Central. An energetic episode that began at 0320 on 22 September produced an ash plume that rose 2 km and drifted WSW. Another episode accompanied by tremor which began at 1345 generated an ash plume that rose 1 km. Surficial activity significantly decreased on 23 September; a few short episodes were detected but weather clouds prevented observations. Seismicity remained high, characterized by very-long-period events. Seismicity decreased on 24 September and activity was very low through the afternoon of 25 September; a few minor eruptions were detected. At 2110 on 25 September an eruption was detected seismically, but cloud cover blocked views. Ashfall and a sulfur odor was reported in Valle Central communities, including San José and Heredia. An eruption at 1225 on 26 September produced an ash plume that rose 1 km and drifted NW. Cloud cover again prevented visual observations of activity that began at 1242, and lasted for four hours. Based on the amplitude of the seismic signal, webcam images, and observations from scientists in the field, ash plumes were estimated to rise as high as 2 km. Continuous passive emissions continued to rise as high as 2 km until 1000 on 27 September; between 1000 and 1242 ash plumes rose 300-500 m.

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