Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 11 December – 17 December 2019

Bezymianny | Central Kamchatka (Russia) : Activity at Bezymianny began to increase at the beginning of December, characterized by nighttime crater incandescence, strong fumarolic emissions, a lava flow, and gradually increasing temperatures of a satellite-detected thermal anomaly. KVERT increased the Aviation colour Code to Orange (the second highest level on a four-colour scale) on 13 December.

Nishinoshima | Japan : The Japan Coast Guard (JCG) reported that during an overflight of Nishinoshima on 15 December surveyors observed that explosions were occurring from the main crater of the pyroclastic cone every second to several seconds. Blocks were ejected as high as 300 m above the crater rim; red hot blocks were scattered at the base of the cone. Gray plumes rose from the crater, and lava continued flowing E into the sea. A new crater had opened on the N flank of the cone and effused lava that flowed NW down to the sea. JMA expanded the marine exclusion zone around the island to 2.5 km the next day.

Semisopochnoi | United States : AVO reported that during 10-17 December activity at Semisopochnoi remained elevated, with bursts of tremor and small explosions detected in both seismic and infrasound data. An 80-km-long gas-and-steam plume possibly containing ash was visible in satellite images during 11-12 December. The Aviation colour Code remained at Orange and the Volcano Alert Level remained at Watch.

White Island | North Island (New Zealand) : GeoNet reported that the deadly 9 December eruption at White island modified the active crater area. The basin previously containing a hot acidic lake was mostly filled by debris with numerous, isolated ponds after the event. During overflights observers identified three main vents within a 100-square-meter area. Volcanic tremor significantly increased at around 0400 on 11 December and was accompanied by vigorous steaming and localized mud jetting from the active vent area. By the early evening tremor was at the highest level recorded since the 2016 eruption. On 12 December the Volcanic Alert Level was lowered to 2 (since no more eruptions had occurred since 9 December), though the Aviation colour Code remained at Orange. Later that day tremor levels decreased but remained very high compared to normal levels. Energetic steam-and-mud bursts continued from the active vent area. Gas emissions had increased compared to 10 December measurements. Tremor levels continued to decline during 12-13 December and then significantly dropped later on 13 December. During an overflight on 13 December observers noted small-scale gas jetting and steam bursts from the active vents. High heat flow was confirmed by a glow emanating from the vent area in overnight webcam images during 12-15 December; high-temperature (more than 200 degrees Celsius) volcanic gas was being emitted at a high rate when observed during an overflight on 15 December. GeoNet noted that data from various measurements suggested a magma source not far below the surface, possibly as shallow as tens of meters deep. According to the New Zealand Police the death toll from the 9 December eruption was 15, with two people still missing.