Volcanos

Roundup of Global Volcanic Activity - New Activity for the week of 12 April - 18 April 2023

Bezymianny - Central Kamchatka (Russia) : KVERT reported that the eruption at Bezymianny intensified to a significant explosive phase starting from 1738 on 7 April and ending before 0906 on 8 April (local times). Based on webcam and satellite data ash plumes rose 10-12 km (32,800-39,400 ft) a.s.l. and drifted 2,800 km E. Notable amounts of ash fell at the Apakhonchich station. A daily thermal anomaly from continuing lava effusion was identified in satellite images during 8-14 April.

Nevado del Ruiz - Colombia : Servicio Geológico Colombiano’s (SGC) reported that the eruption at Nevado del Ruiz continued during 11-18 April and was characterized by gas, steam, and ash emissions, thermal anomalies at the lava dome in Arenas Crater, and elevated seismicity. Seismic signals indicating rock-fracturing events continued to be located 2-6 km SW of Arenas Crater at depths of 2-4 km, though on 12 and 16 April signals were also located in the NE sector of the volcano at depths of 0.5-5 km. The number of daily events fluctuated through the week. Additionally, signals indicating fluid movement fluctuated in intensity and were associated with daily ash emissions. On 11 April ash-and-gas plumes rose as high as 2.5 km above the crater rim and drifted SW and NW, causing ashfall in the municipalities of Villamaría (Caldas) and Filandia (Quindío). Ash-and-gas plumes that rose as high as 1.8 km drifted SW and NW on 12 April, and 1.5 km high plumes drifted SW on 13 April. During 0759-1113 on 14 April and from 1515 on 14 April to 1257 on 15 April seismicity activity intensified and corresponded to continuous ash emissions that rose as high as 1.5 km and drifted SW. These emissions were visible from the municipalities of Murillo and Manizales. Later that day gas-and-ash plumes rose to 1.6 km and drifted NW. According to a news article 87 people had self-evacuated after the government called for the voluntary evacuation of around 2,500 families on 5 April.

Sheveluch - Central Kamchatka (Russia) : According to KVERT a significant eruption at Sheveluch began at 0110 on 11 April, local time. During the most intense phase of activity ash plumes possibly rose as high as 15.8 km (52,000 ft) a.s.l., a significant sulfur dioxide signature was detected in the plume, pyroclastic flows traveled notable distances, and ash-and-lapilli-fall impacted residents. Strong explosions continued during the morning of 12 April. At 0730 on 12 April satellite images showed ash plumes rising to 8 km (26,200 ft) a.s.l., though parts of the large ash plume generated earlier extended 600 km SW and 1,050 km ESE. The explosions weakened by 1710 when ash plumes were only rising to 4.5 km (14,800 ft) a.s.l. and drifting ESE; at 1801 KVERT issued a Volcano Observatory Notice for Aviation (VONA) lowering the Aviation Color Code to Orange. By 2310 ash extended as far as 3,000 km E. KVERT noted that ash deposits in Klyuchi were as deep as 8.5 cm, and ashfall was reported in Kozyrevsk, Maiskoye, Atlasovo, Lazo, and Esso during 10-12 April. According to news sources, the ash-and-gas plumes drifted E toward the Aleutian Islands and reached the Gulf of Alaska by 13 April, causing flight disruptions. More than 100 flights involving Alaska airspace were cancelled due to the plume. Flight cancellations were also reported in NW Canada (British Columbia) during 13-14 April. Alaskan flight schedules were mostly back to normal by 15 April, with only minor delays and far fewer cancellations; a few cancellations continued to be reported in Canada. On 13 April Kamchatka Volcanological Station (KVS) volcanologists inspected pyroclastic flow deposits that had stopped about 600 m from the Klyuchi-Ust-Kamchatsk federal highway. They walked about 1 km through deep snow (1 m) covered in 6 cm of ash and noted that some parts of the deposits were hot. Steam rose from downed smoldering trees. One picture showed a large block lodged high up in a bare tree. They also noted that the pyroclastic flow deposits were thin with very few large fragments, different from previous flows from Sheveluch. Clearing weather on 15 April revealed that most of the previous lava-dome complex was gone and there was a new crater 1 km in diameter from which voluminous steam-and-gas plumes were rising. Evidence suggested that there had been a directed blast to the SE, and pyroclastic flows traveled more than 20 km.