Volcanos

Global Volcanic Activity - Ongoing Activity for the week of 24 April - 30 April 2019

Agung | Bali (Indonesia) : PVMBG reported that at 0534 on 30 April a dense gray ash plume from Agung rose 1 km above the crater rim and drifted E. The Alert Level remained at 3 (on a scale of 1-4) with the exclusion zone set at a 4-km radius.

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 24-27 and 29-30 April ash plumes from Dukono rose to altitudes of 1.5-2.1 km (5,000-7,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and visitors were warned to remain outside of the 2-km exclusion zone.

Ebeko | Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 21-22 and 24 April that sent ash plumes up to 2.5 km (8,200 ft) a.s.l. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Karymsky | Eastern Kamchatka (Russia) : KVERT reported that a weak thermal anomaly over Karymsky was visible in satellite images during 18-21 April. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Krakatau | Indonesia : PVMBG reported that there were 19 events during 22-28 April recorded by Anak Krakatau’s seismic network; no emissions from the events were visually observed, even though the visibility was a mix of clear and foggy conditions. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to remain outside of the 2-km radius hazard zone from the crater.

Merapi | Central Java (Indonesia) | 7.54°S, 110.446°E | Elevation 2910 m

PVMBG reported that during 22-28 April the lava dome at Merapi continued to grow slowly, with any extruded material channeled into the SE-flank Gendol River drainage. White emissions rose 70 m. Five block-and-ash flows traveled as far as 1.2 km in the Gendol drainage on 24 April. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to remain outside of the 3-km exclusion zone.

Nevados de Chillan | Chile : SERNAGEOMIN reported that the lava dome in Nevados de Chillán’s Nicanor Crater continued a cycle of slow growth and partial destruction from explosions during 23-30 April. The pulsating, generally white, emissions were sometimes gray and rose no higher than 900 m above the crater rim and drifted NW, S, and SE. Nighttime webcam data showed incandescent ejecta around the crater. The Alert Level remained at Orange, the second highest level on a four-colour scale, and residents were reminded not to approach the crater within 3 km. ONEMI maintained an Alert Level Yellow (the middle level on a three-colour scale) for the communities of Pinto, Coihueco, and San Fabián.

Poas | Costa Rica : OVSICORI-UNA reported that on 24 April a very diffuse ash emission rose from Poás. Incandescence from vent A (Boca Roja) was sometimes visible during 24 and 27-28 April.

Reventador | Ecuador : IG reported that during 23-30 April periodic seismic data from Reventador’s network indicated a high level of seismic activity, including explosions, long-period earthquakes, harmonic tremor, and signals indicating emissions. Steam, gas, and ash plumes sometimes rose higher than 1 km above the crater rim and drifted N, NW, W, and SW. Incandescent blocks were observed rolling 500-800 m down the flanks. Inclement weather sometimes prevented visual observations.

Ruapehu | North Island (New Zealand) : GeoNet reported that the period of high water temperatures at Ruapehu’s summit Crater Lake along with elevated tremor levels was over. Tremor levels began to decline on 16 April and by 29 April was described as weak. The lake water reached a peak temperature of 44 degrees Celsius on 19 April and then began cooling; the temperature was 39 degrees Celsius by 29 April. The report noted that the probability of an eruption during a heating cycle had decreased with the decreasing activity. The Volcanic Alert Level remained at 1 (minor volcanic unrest) and the Aviation colour Code remained at Green.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch’s lava dome was identified daily in satellite images during 18-26 April. Ash plumes were visible drifting 300 km NE during 22-23 April. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Turrialba | Costa Rica : OVSICORI-UNA reported that a diffuse ash emission rose from Turrialba on 24 April, and an emission with low ash content drifted N on 26 April. At 0722 on 27 April a small, short-duration eruption generated an ash plume that rose less than 100 m above the crater rim.

Veniaminof | United States : On 30 April AVO lowered the Aviation colour Code for Veniaminof to Green and the Volcano Alert Level to Normal, noting that signs of unrest had continued to decline over the previous four months since the eruption ended in early January. Low-level tremor, slightly elevated surface temperatures, and minor steam emissions continued and considered typical activity for a post-eruptive period.