Volcanos

Roundup of Global Volcanic Activity - New Activity for the week of 19 April - 25 April 2023

Bezymianny - Central Kamchatka (Russia) : KVERT reported that a daily thermal anomaly from continuing lava effusion at Bezymianny was identified in satellite images during 14-20 April. Gas-and-steam emissions were visible and occasional collapses from the growing lava dome produced avalanches of hot material.

Nevado del Ruiz - Colombia : Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that the eruption at Nevado del Ruiz continued during 18-25 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 were located 1-3 km W, SW, NE, and E of Arenas Crater and below the crater, at depths of 0.4-6.2 km. The largest event, a M 1.7, was recorded at 1735 on 24 April and was located 4.1 km E of the crater, at a depth of 3.2 km. The event was felt by residents in the Lagunilla river canyon. Additionally, signals indicating fluid movement fluctuated in intensity and were associated with daily gas-and-steam emissions, sometimes containing ash, that rose as high as 1.8 km above the crater rim. At 0711 on 18 April an ash plume rose 1.8 km above the crater rim and drifted SE, causing ashfall in the municipality of Anzoátegui, Tolima. At 2235 on 19 April and at 2248 on 21 April ash plumes rose 1.8 km and drifted SSE. Gas emissions with possible ash rose as high as 1.3 km and drifted SW and E during 20-21 April. Pulsating ash emissions were seen in webcam images during 23-25 April.

Rincon de la Vieja - Costa Rica : OVSICORI-UNA reported that phreatic eruptions, detected seismically but often with observed emissions, continued to occur at Rincón de la Vieja during 18-25 April. Several eruptive events recorded during 18-21 April produced gas-and-steam emissions that rose as high as 1.5 km above the crater rim. A strong eruptive event at 1550 on 21 April generated a dense plume of material that rose 500 m above the crater rim and then collapsed, producing a pyroclastic flow and lahars on the N flank. A steam-and-gas plume with minor ash content rose 4-5 km above the crater rim. Strong tremor levels and near-continuous gas emissions were recorded after the event. That same day OVSICORI-UNA noted that during the previous week sulfur dioxide emissions were 221 tons per day on average, though emissions spiked to close to 5,000 tons per day after several of the phreatic events. During 22-24 April nearly continuous gas emissions continued to be visible and strong tremor continued to be recorded by the seismic network. Small phreatic events were recorded at 1904 on 22 April and at 0054 and 0629 on 24 April. Small phreatic events at 2250 on 23 April and 0630 on 24 April produced steam-and-gas plumes that rose no higher than 500 m above the crater rim.

Sheveluch - Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 14-20 April. During 14-15 April ash plumes rose to 6 km (19,700 ft) a.s.l. and drifted 700 km NW. During 17-19 April plumes of unconsolidated ash resuspended from the flanks by wind rose to 4 km (13,100 ft) a.s.l. and drifted as far as 224 km NW. The sulfur dioxide gas portion of the eruption cloud produced during the notable 11-12 April activity continued to drift E; by 21 April the leading edge of the plume was over part of Greenland. T