Roundup of Global Volcanic Activity – Ongoing activity for the week 22 March – 28 March 2023
Ahyi – Mariana Islands (USA) : Unrest at Ahyi Seamount continued during 21-28 March. A plume of discolored water was observed in high-resolution satellite images acquired on 21 and 22 March. No observations indicated that activity has breached the ocean surface. One possible underwater explosion was detected by pressure sensors on Wake Island, 2,270 km E, during 26-27 March.
Aira – Kyushu (Japan) : JMA reported ongoing eruptive activity at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) during 20-27 March, with crater incandescence visible nightly. Two explosions recorded on 21 and 22 March produced ash plumes that rose 1.2 km above the crater rim and ejected large blocks 1-1.3 km from the vent. Two eruptive events during 24-27 March produced volcanic plumes that rose 1.1 km.
Asosan – Kyushu (Japan) : The amplitude of volcanic tremor signals at Asosan increased in December 2022, and then further intensified on 30 January. The amplitude fluctuated at high levels for a few weeks, and then decreased on 19 February and again on 14 March. Daily sulfur dioxide emissions had exceeded 1,000 tons per day starting in December 2022; emissions declined to below that threshold by mid-January and remained at lower levels.
Cotopaxi – Ecuador : IG reported that eruptive activity at Cotopaxi was ongoing during 22-28 March. Gas-and-steam emissions were visible during 21-24 March rising as high as 1 km above the crater rim and drifting E; weather clouds prevented views of the volcano on 23 March. Ash emissions rose 500-800 m above the crater rim and drifted SW and SE during 25-26 March. Ash plumes rose 1.1 km above the crater rim and rifted SE, NE, and NW on 27 March. Ash plumes rose as high as 2 km above the crater rim on 28 March and drifted NW, causing minor ashfall in the Machachi parish on the N flank, in Parque Nacional Cotopaxi.
Ebeko – Paramushir Island (Russia) : KVERT reported that moderate activity at Ebeko was ongoing during 16-23 March. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during 18 and 21-22 March generated ash plumes that rose as high as 2.8 km (9,200 ft) a.s.l. and drifted NE and E. Ash plumes were identified in satellite images drifting 76 km E during 22-23 March.
Fuego – South-Central Guatemala : INSIVUMEH reported that 4-10 explosions per hour recorded at Fuego during 22-28 March generated ash plumes that rose as high as 1.1 km above the crater rim and drifted at least 25 km in multiple directions. Ashfall was reported almost daily in areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), Finca Palo Verde, La Rochela, Sangre de Cristo (8 km WSW), El Porvenir (8 km ENE), Finca Asunción, Aldeas, and San Pedro Yepocapa (8 km NW). Ashfall was not confirmed during 23-24 March Explosions ejected incandescent material up to 200 m above the crater. Daily block avalanches descended the flanks in various directions towards the Ceniza (SSW), Santa Teresa, Seca (W), Taniluya (SW), Trinidad (S), Las Lajas (SE), Honda (E), and El Jute (ESE) ravines, sometimes reaching vegetated areas. Shockwaves caused structures to shake in communities around the volcano.
Great Sitkin – Andreanof Islands (USA) : AVO reported that a 23 March satellite image confirmed that lava continued to slowly erupt at the summit of Great Sitkin, producing a thick lava flow. The flow advanced to the E and likely continued to be fed through 28 March.
Karangetang – Sangihe Islands : Webcam images of Karangetang posted in PVMBG daily reports during 23-28 March showed incandescent material at the summit Main Crater (S crater) and on the flanks.
Krakatau – Sunda Strait : PVMBG reported that the eruption at Anak Krakatau continued during 22-29 March and multiple ash plumes were visible rising from the vent during 28-29 March. Ash plumes recorded at 0412, 0743, 1221, 1513, and 1935 on 28 March were dense and dark gray and rose as high has 2.5 km above the summit. The ash plumes drifted NE and W. Webcam images captured incandescent material being ejected above the vent at 0415 and around the summit area at 2003. At 0041 on 29 March a dense dark ash plume rose 600 m and drifted W. A webcam image from 0047 showed incandescent material at the vent.
Lewotolok – Lembata Island : PVMBG reported that the eruption at Lewotolok was ongoing during 22-28 March. Daily ash plumes, sometimes dense, were visible rising as high as 800 m above the summit and drifting mainly W and NW. VONAs issued on most days described dense gray or gray-to-white ash plumes at 0517, 1623, and 2016 on 22 March, at 1744 on 24 March, at 0103 on 26 March, at 0845 and 1604 on 27 March, and at 0538 on 28 March. A webcam image at 2220 on 22 March showed incandescent material around the summit area and being ejected above the summit. Another webcam images at 0103 on 26 March captured a Strombolian explosion at the summit.
Merapi – Central Java : BPPTKG reported that the eruption at Merapi (on Java) continued during 17-23 March and seismicity remained at high levels. The SW lava dome produced 160 lava avalanches that traveled as far as 1.8 km down the SW flank (upstream in the Bebeng and Boyong drainages). Two pyroclastic flows traveled 1.3 km down the SW flank, upstream of the Bebeng/Krasak drainage. Morphological changes to the SW lava dome were evident in webcam images due to continuing collapses of material, though the volume remained unchanged at 1,686,200 cubic meters.
Santa Maria – Southwestern Guatemala : INSIVUMEH reported that the Santa Maria-Santiaguito lava dome complex remained highly active during 22-28 March. On most days steady degassing from the dome produced gas plumes that drifted S and SW. Incandescence from the dome and along lava flow margins was visible most nights or early mornings. The lava flow that extended 4.3 km down the SW flank in the San Isidro and Zanjón Seco drainages was active. Activity from the lava dome included explosions and avalanches, and small pyroclastic flows during 22-23 March. Daily weak to moderate explosions generated ash plumes up to 1 km above the crater that drifted SW and W, and avalanches traveled down multiple flanks.
Semeru – Eastern Java : PVMBG reported that the eruption at Semeru continued during 22-28 March, with daily emissions of dense ash plumes. At 0605 and 0810 on 23 March gray and white-to-gray ash plumes rose 800 m above the summit and drifted NW and SW. At 0548 on 24 March a white-to-gray ash plume rose 1 km and drifted S. On 25 March at 0600 a white-to-gray ash plume rose 500 m and drifted S and SW, at 0705 a gray ash plume rose 700 m and drifted SE and S, and at 0738 a gray-to-brown ash plume rose 1.2 km and drifted SE. At 0619 and 0659 on 26 March dense white-to-gray ash plumes rose 1 km and drifted SE. At 0756 on 27 March a white-to-gray ash plume rose 800 m and drifted S. At 0130 on 28 March a dense gray ash plume drifted NE and at 0759 a somewhat dense white-to-gray plume rose 800 m and drifted N.
Semisopochnoi – Aleutian Islands (USA) : AVO reported that low-level unrest continued at Semisopochnoi during 22-28 March. Steam emissions from the N crater of Mount Young were visible during 22 and 26-27 March. No explosive activity was detected in seismic or infrasound data.
Sheveluch – Central Kamchatka (Russia) : KVERT reported that the ongoing eruption at Sheveluch was generally characterized by explosions, hot avalanches, lava-dome extrusion, and strong fumarolic activity. A daily thermal anomaly was identified in satellite images during 16-23 March.
Stromboli – Aeolian Islands (Italy) : INGV reported that both explosive and effusive activity at Stromboli occurred during 20-26 March, though inclement weather conditions prevented views on most days. Activity was centered at three vents in Area N within the upper part of the Sciara del Fuoco, and from four vents in Area C-S (South-Central Crater) on the crater terrace. Explosions at two vents in the N1 crater and one vent in the N2 crater in Area N were low to medium intensity and ejected coarse material (bombs and lapilli) 80-150 m at a rate of 6-12 explosions per hour. Explosive activity at three active vents at the S2 sector in Area C-S ejected coarse material generally as high as 150 m above the vent at a rate of 5-7 explosions per hour; material was ejected as high as 300 m on 23 March. Sector C was characterized by occasional low-intensity explosive activity through the week and intense spattering on 22 March. No activity was recorded at sector S1. A strong explosion at 1549 on 25 March at Area C-S and was followed by two minor explosions; the sequence lasted about three minutes. A lava overflow event at one of the N1 vents began at 2242 on 23 March and was preceded by spattering activity in Area N. After about an hour lava flowed along the Sciara del Fuoco in the ravine that had formed in October 2022. The flow rate notably increased during 0200-0400 on 26 March and caused avalanches of material from collapses at the advancing flow front. By that afternoon the flow was cooling down and no longer being fed. It was unknown due to weather conditions if material reached the coastline.
Suwanosejima – Ryukyu Islands (Japan) : JMA reported that the eruption at Suwanosejima’s Ontake Crater continued during 20-27 March. Eruptive activity including three explosions sent ash plumes as high as 2 km above the rim and ejecting large blocks as far as 300 m from the vent. Crater incandescence was visible nightly. Occasional ashfall was reported in Toshima village (3.5 km SSW).
Villarrica – Central Chile : The eruption at Villarrica was ongoing during 21-28 March. POVI reported that on 21 March Strombolian explosions ejected material 100 m above the crater rim. SERNAGEOMIN reported that at 0551 on 24 March a long-period earthquake was associated with low-intensity crater incandescence. According to POVI a cone with a vent that was about 13 m in diameter had formed on the crater floor and was visible during a recent overflight. Sometimes lava fountains rose over 100 m. At 2249 on 26 March Strombolian explosions ejected incandescent material more than 110 m above the crater rim.