Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 28 March - 3 April 2018

Aira | Kyushu (Japan) : JMA reported that there were 16 events at Minamidake crater (at Aira Caldera’s Sakurajima volcano) during 26 March-2 April, 12 of which were explosive. Tephra was ejected as far as 900 m from the crater. At 1541 on 26 March an explosion generated an ash plume that rose 3.4 km above the crater rim. An explosion recorded at 0740 on 1 April produced an ash plume that rose 3 km. Crater incandescence was visible the morning of 27 March and at night during 30 March-1 April. During 30 March-2 April there were three events at Showa crater. An event at 1611 on 1 April ejected tephra 300-500 m from the crater, and produced a very small pyroclastic flow (the first since 3 June 2016) that traveled 800 m E. A plume rose 1.7 km above the crater rim, up into weather clouds. The previous eruption at Showa crater occurred on 8 January. The Alert Level remained at 3 (on a 5-level scale).

Ambae | Vanuatu : Based on satellite data, webcam and VGO observations, and wind model data, the Wellington VAAC reported that during 28 March-3 April ash plumes from the vent at Ambae’s Lake Voui rose to altitudes of 2.3-6.1 km (8,000-20,000 ft) a.s.l. and drifted in multiple directions. News articles noted that ashfall continued to damage crops and buildings, and contaminate water.

Dieng Volcanic Complex | Central Java (Indonesia) : PVMBG reported that a phreatic eruption at the Sileri Crater lake (Dieng Volcanic Complex) occurred at 1342 on 1 April, ejecting mud and material 150 m high, and up to 200 m in multiple directions. The event was preceded by black emissions that rose 90 m, and then diffuse white emissions that rose 150 m. The report noted that there were not many tourists in the area due to rainy weather; tourists are not permitted within 200 m of the crater rim.

Kikai | Japan : JMA reported that the number of volcanic earthquakes at Satsuma Iwo-jima, a subaerial part of Kikai’s NW caldera rim, was low during 27 March-2 April after an increase recorded during 22-23 March. White plumes rose as high as 1.8 km above the Iwo-dake lava dome. Incandescence from the crater was visible at night during 27-28 March. The Alert Level remained at 2 (on a 5-level scale).

Kirishimayama | Kyushu (Japan) : Based on observations during overflights on 28 March and 2 April, JMA reported that the crack on the W flank of Shinmoedake (Shinmoe peak), a stratovolcano of the Kirishimayama volcano group, continued to widen. White emissions rose as high as 500 m above the crater rim. Several high-temperature regions around the margins of the lava in the crater, and from the flow on the NW flank, were detected on 28 March. The lava flow on the NW flank advanced 85 m from 9-29 March. Sulfur dioxide emissions were 300 tons/day on 30 March. The number of volcanic earthquakes began to decline after 26 March; though from 0014 to 1430 on 3 April the number increased to 239. Many low-frequency earthquakes with shallow hypocenters continued to be recorded. The Alert Level remained at 3 (on a scale of 1-5).

Piton de la Fournaise | Reunion Island (France) : OVPF reported that intermittent inflation at Piton de la Fournaise had been detected since the end of the last eruption on 28 August 2017. Seismicity began increasing the last two weeks in February. Seismicity fluctuated during March; peaks were recorded on 28 and 31 March, with volcano-tectonic earthquakes occurring less than 2 km below the summit area. An enrichment of carbon dioxide and sulfur dioxide in summit fumaroles was noted on 23 March. A seismic crisis began at 0300 on 3 April, and along with deformation, indicted magma migration towards the surface. An eruption began at 1040 on the N flank, just below the rampart at the Nez Coupé de Sainte Rose area. During an overflight, scientist observed a 1-km-long fissure, divided in seven segments, with two active vents producing lava fountains. At 1600 many landslides were recorded by the seismic network in the active area. The eruption ended At 0400 on 4 April, though a few landslides were recorded through 1530.