Volcanos

Roundup of Global Volcanic Activity - New activity for the week 5 April - 12 April 2023

Ambae - Vanuatu : The cone in Ambae’s Lake Voui continued to produce emissions consisting of steam, volcanic gases, and ash that drifted downwind during 5-7 April, based on reports from Vanuatu Meteorology and Geo-Hazards Department (VMGD) and Wellington VAAC notices. On 5 April low-level intermittent plumes of gas and ash rose as high as 2.5 km above the crater rim and drifted W and SW. A loud explosion followed by a dark ash emission was possibly reported. Webcam images from 2100 showed incandescence above the crater and reflected in the clouds. Intermittent emissions of gas-and-steam and gas-and-ash were visible on 7 April. Plumes rose an estimated 3 km above the crater rim and drifted E. Webcam images during 0107-0730 on 7 April showed continuing ash emissions.

Bezymianny - Central Kamchatka (Russia) : KVERT reported an ongoing eruption at Bezymianny generally characterized by gas-and-steam emissions and occasional collapses of hot material from the flanks of the summit lava dome. A thermal anomaly over the summit persisted in satellite images during 31 March-6 April. Diffuse ash plumes drifted as far as 550 km E during 2 and 5-6 April. On 6 April volcanologists at the Kamchatka Volcanological Station (KVS) traveled to the Apakhonchich station to assess Bezymianny, take aerial photos, and install monitoring equipment. They observed frequent collapses of the crater rim and ash plumes that drifted NE towards Apakhonchich. KVERT stated that at 1326 local time on 7 April a satellite image showed an ash plume drifting 150 km E at altitudes of 5.5-6 km (18,000-19,700 ft) a.s.l. A satellite image from 1600 local time that same day showed an ash plume extending as far as 230 km ESE. KVERT noted that ash emissions were intensifying, likely caused by hot avalanches from a growing lava dome. On 7 April KVS volcanologists traveled to Ambon to collect ash. They reported that a notable eruption began at 1730 local time, and within 20 minutes a large ash plume had risen to 10 km and drifted NW. KVERT reported that the strong explosive phase began at 1738 local time. Based on webcam and satellite data ash plumes rose 10-12 km (32,800-39,400 ft) a.s.l. and drifted SE. Explosions were clearly audible at 20 km distance and were heard for 90 minutes, according to KVS. Significant amounts of ash fell at the Apakhonchich station, and the snow turned gray. The volcanologists had returned to KVS by the evening, and they were covered in ash. Ashfall continued until the morning of 8 April. In a Volcano Observatory Notice for Aviation (VONA) issued at a 0906 on 8 April, KVERT stated that the strong eruptive phase was over.

Nevado del Ruiz - Colombia : Servicio Geológico Colombiano’s (SGC) reported that the number of daily events detected by the seismic network at Nevado del Ruiz fluctuated during 3-8 April but declined overall. Earthquakes were generally located 2-5 km SW of Arenas Crater at depths of 3-4 km. On 9 April SGC noted that daily counts of events were no longer going to be posted in their daily reports and instead the focus will be on the location of the earthquakes. Gas emissions had also decreased in density. That same day Gestión del Riesgo de Desastres (UNGRD) reported that 2,000-2,500 families had been identified as living in high-risk areas and requested that local authorities expedite a preventive evacuation; families that had evacuated were staying with family and friends and not in evacuation shelters. During 3-11 April the earthquakes were associated with daily emissions of gas-and-steam and gas-and-ash plumes. Ash-and-gas plumes rose as high as 1.5 km above the crater rim on 3 April and drifted NW and SW. During 6-7 April several pulsating ash emissions were observed in webcam images and by residents of La Cabaña (Murillo, Tolima). The emissions rose as high as 1.5 km and drifted SE and NE. Webcam images and La Cabaña residents again saw ash emissions on 10 April, rising as high as 1.8 km and drifting E and NE. Thermal anomalies from Arenas Crater were periodically visible through the week.

Sheveluch - Central Kamchatka (Russia) : On 28 March the Kamchatka Volcanological Station (KVS) reported that activity had increased at Sheveluch during the previous few days. Incandescence at the summit of the lava dome was constant and the focus of activity shifted from the E side to the NE side. KVERT reported that the ongoing eruption was generally characterized by explosions, hot avalanches, lava-dome extrusion, and strong fumarolic activity. A daily thermal anomaly was identified in satellite images during 30 March-6 April. Satellite images showed an ash plume drifting 250 km E and SE. Seismic data around 0054 local time on 11 April indicated a significant increase in activity, as reported by the Institute of Volcanology and Seismology, Far Eastern Branch, Russian Academy of Sciences (IVS FEB RAS). According to the Tokyo VAAC the ash plume had risen to 15.8 km (52,000 ft) a.s.l. by 0110 and was drifting NW. By 0158 the plume extended over a 75 x 100 km area. KVS reported that significant pulses of activity occurred at around 0200, 0320, and then a stronger phase started around 0600. Video of the rising plume was taken at around 0600 from near Békés (3 km away) by Levin Dmitry, who reported that a pyroclastic flow traveled across the road behind him as he left the area. Ashfall began in Klyuchi (45 km SW) at 0630, and the large black ash plume had blocked the daylight by 0700. A large ash plume had risen to 10 km (32,800 ft) a.s.l. and drifted 100 km W. According to IVS FEB RAS the cloud was 200 km long and 76 km wide by 0830, and was spreading W at altitudes of 6-12 km (19,700-39,400 ft) a.s.l. KVS reported that at about 0930 the plume drifted over Kozyrevsk (112 km SW) and turned the day to night. Almost constant lightning strikes in the plume were visible and sounds like thunderclaps were heard until about 1000. The sky lightened up in Kozyrevsk at about 1030; residents in Klyuchi reported continuing darkness and ashfall at 1100. As the day went on the light had a reddish-brown hue due to the ash in the atmosphere. In some areas ashfall was 6 cm deep and some residents reported dirty water coming from their plumbing. At 1150 an ash cloud 400 km long and 250 km wide was spreading W at altitudes of 5-20 km (16,400-65,600 ft) a.s.l., according to IVS FEB RAS. KVERT issued a VONA at 1155 noting that ash had risen to 10 km and that it had extended 340 km NNW and 240 km WSW. According to Simon Carn about 0.2 Tg of sulfur dioxide in the plume was measured in a satellite image acquired at 1343. A satellite image at 1748 showed ash plumes rising to 8 km (26,200 ft) a.s.l. and drifting 430 km WSW and S, based on a VONA. Residents of Klyuchi measured ashfall as thick as 8.5 cm, according to the Kamchatka Branch of Geophysical Services (KBGS; Russian Academy of Sciences). In a VONA issued at 0748 on 12 April KVERT stated that strong explosions were continuing. Ash plumes from explosions rose to 8 km and drifted ESE. The larger ash cloud continued to drift and had extended 600 km SW and 1,050 km ESE. IVS FEB RAS scientists photographed the terminal part of a pyroclastic flow that had traveled 19 km SSE the day before, which had stopped a few hundred meters from a bridge on the road between Kliuchi and Petropavlovsk-Kamchatsky.