Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 18 July – 24 July 2018

Asamayama | Honshu (Japan) : JMA stated that during 16-23 July white plumes rose as high as 300 m above Asamayama’s summit crater. Weak crater incandescence was visible for the first time since 23 December 2017. The Alert Level remained at 2 (on a scale of 1-5).

Etna | Sicily (Italy) : INGV reported that during 16-22 July gas plumes rose from Etna’s summit crater; low-energy Strombolian activity also occurred from three vents at the bottom of Northeast Crater (NEC) and from two vents in Bocca Nuova. The activity was mostly confined to the craters, with material falling back into the craters, though occasionally incandescent lava was ejected about 100 m above the crater rim. The activity sometimes generated ash emissions that dissipated near the summit.

Krakatau | Indonesia : Based on satellite and wind model data, the Darwin VAAC reported that during 18-20 July ash plumes from Anak Krakatau rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted NE, E, SW, and W. The Alert Level remained at 2 (on a scale of 1-4); residents and visitors were warned not to approach the volcano within 1 km of the crater.

Nishinoshima | Japan : Based on Japan Coast Guard (JCG) observations, JMA reported that a very small eruption at Nishinoshima occurred at 1124 on 12 July, producing a brownish plume that rose from near the crater. During an aerial survey, JCG noted deposits 400 m from the vent. No thermal anomalies were detected. The report warned people to stay at least 500 m away from the crater.

Semeru | Eastern Java (Indonesia) : Based on analysis of satellite images, the Darwin VAAC reported that on 20 July a minor eruption at Semeru generated an ash plume that rose to an altitude of 4.9 km (16,000 ft) a.s.l. and drifted SW.

Sierra Negra | Isla Isabela (Ecuador) : IG reported that the eruption at Sierra Negra continued through 23 July, and continued to vary in intensity. Four fissures had initially opened on 26 June, at the start of the eruption. Fissure 1 is 4 km long and located at the edge of the caldera in the area of Volcán Chico. Lava flows from this fissure traveled 7 km down the flanks, and 1.7 km within the interior of the caldera, covering an area of 16.1 square kilometers. Fissure 2 is about 250 m long, located NW of the caldera, and produced lava flows that traveled 3 km and covered an area of 2.3 square kilometers. Fissure 3, located W of the caldera, is 250 m long and produced lava flows that descended the flanks 2 km, covering an area of 0.3 square kilometers. Fissures 1-3 were active until 27 June. Fissure 4, 250 m long and located on the NW flank, continued to be active. Lava from this fissure reached the ocean between 9 and 10 July, and by 16 July had covered an area of 11.6 square kilometers (30.4 square kilometers was covered by lava from all four fissures).

Villarrica | Chile : POVI reported that sometime during mid-morning on 18 July webcam images captured two vapor-and-gas emissions with some ash rising from Villarrica. Between 1100 and 1200 that same day a thermal anomaly (the largest since December 2017) was identified in satellite images. Crater incandescence was visible later that day. An earthquake, possibly a volcano-tectonic signal, was detected at about 0627 on 20 July, a few hours after gas-and-steam emissions decreased. Crater incandescence was visible on 23 July.

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