Volcanos

Roundup of Global Volcanic Activity - New Activity for the week of 24 May - 30 May 2023

Ahyi - Mariana Islands (USA) : Unrest at Ahyi Seamount continued during 21-30 May. Underwater events were detected by pressure sensors on Wake Island (2,270 km E) at least during 24-25 and 28-30 May. The events were possibly related to underwater explosions or earthquakes at the volcano. No activity was visible in cloudy or partly cloudy satellite images.

Etna - Sicily (Italy) : INGV reported that during 23-24 May activity at Etna was characterized by weak intra-crater explosive activity at the SE Crater and minor incandescence at Bocca Nuova Crater based on webcam images. A drone survey of the lava flows and tephra deposits emplaced during the 21 May paroxysmal eruption was conducted on 27 May. Lava flows had traveled 2.3 km, reaching 2,650 m elevation. During a field inspection on 28 May volcanologists observed gas emissions rising from Bocca Nuova and fumarolic activity at both Voragine Crater and NE Crater.

Karangetang - Sangihe Islands : Webcam images of Karangetang published in PVMBG daily reports periodically showed incandescence at Main Crater (S crater) and from material on the flanks of Main Crater during 23-30 May. Incandescence at the summit was most intense in the webcam images from 2332 on 26 May and 2304 on 29 May; the material on the flanks was brightest in the 29 May image. White gas-and-steam plumes were visible on most days rising as high as 150 m above the summit and rifting in various directions.

Nyamulagira - DR Congo : On 28 May the Observatoire Volcanologique de Goma (OVG) reported that the lava flows on Nyamulagira’s upper W flank had begun to cool and solidify. By 29 May seismicity had returned to levels similar to those recorded before the 17 May increase in activity. Lava effusion continued but was confined to the summit crater; incandescence above the crater was periodically visible.

Popocatepetl - Mexico : CENAPRED reported that during 23-30 May activity at Popocatépetl consisted of seismic tremors, very few minor and moderate explosions, near-constant emissions of steam, gas, and sometimes ash, and ejections of incandescent material. Overall activity slightly decreased during the week. A total of approximately 140 hours of high-frequency tremors of variable duration and intensity were recorded. A M 1.2 volcano-tectonic earthquake was recorded at 0340 on 24 May. Less than two hours later, at 0503, a minor explosion generated an ash plume that rose to 1 km above the summit and ejected incandescent material onto the flanks. A moderate explosion occurred at 1343. The Washington VAAC reported continuous ash emissions that rose 8.5-10.7 km (28,000-35,000 ft) a.s.l. and drifted SE. Ashfall was reported in Nealtican (21 km E), San Pedro Cholula (34 km E), San Andrés Cholula (36 km E), Tzicatlacoyan (65 km E), Tianguismanalco (22 km SE), Atlixco (25 km SE), Huaquechula (30 km SE), Ocoyucan (33 km SE), San Diego La Mesa Tochimiltzingo (39 km SE), San Juan Atzompa (71 km SE), Tehuitzingo (85 km SE), Tepexi de Rodríguez (88 km SE), Atzitzihuacán (23 km S), and Tilapa (48 km S). Emissions were sometimes continuous during the night of 24 May into the early morning of 25 May; the plumes drifted SE and were occasionally visible in webcam images. According to the VAAC ash emissions rose 7.6-8.5 km (25,000-28,000 ft) a.s.l. and drifted S, SSE, and SE. Ashfall was reported at 0045 in Atlixco, San Pedro Cholula, and the capital of Puebla. Minor ashfall was reported at 0600 in the municipality of Tetela del Volcan of Estado de Morelos. Incandescent material was ejected onto the flanks close to the crater on 25 May. The Secretary of Navy (SEMAR) conducted a drone flight during the morning of 25 May to collect information about crater activity for the Comité Científico Asesor (CCA), or Scientific Advisory Committee. During a meeting on 26 May that included the CCA, CENAPRED, CNPC, and other agencies it was shared that the drone footage of the crater showed no new lava dome, and that ash and incandescent material had significantly filled in the inner crater. Periods of continuous or nearly continuous ash emissions were recorded during 26-30 May and incandescent material was sometimes ejected short distances from the crater rim. At 1726 on 26 May a minor explosion generated steam, gas, and ash plume and ejected incandescent material. At 1926 on 29 May a minor explosion was recorded. During 26-30 May ash, steam, and gas emissions rose 5.2-7.9 km (17,000-26,000 ft) a.s.l. and drifted SE, E, and ESE according to the VAAC. Ashfall was reported in Nopalucan (87 km NE), San Pedro Cholula (34 km E), Cuautlancingo (38 km E), Puebla Capital, Amozoc (61 km E), Chietla (56 km S), Tlapanalá (39 km SE), Nopalucan (87 km NE), Tepexco (43 km S), Chila de la Sal (104 km S), Chila de las Flores (144 km SE), Tulcingo del Valle (111 km S), Atzala (53 km S), Xochiltepec (53 km SE), Yecapixtla (30 km SW), Amecameca (18 km NW), Atlixco, Atzitzihuacán (23 km S), Ayapango (21 km NW), San Pedro Benito Juárez (10-12 km SE), Acatlán de Osorio, Tlacotepec (110 km SE), Ecatzingo (15 km SW), Tochimilco (16 km SSE), Hueyapan (17 km SW), Tetela del Volcán, Tianguismanalco (22 km SE), Atlixco, Tenango del Aire (29 km NW), Huaquechula, Chautla (36 km NE), and Zacualpan (31 km SW). The eruption continued to impact residents. Air quality alerts were issued in Puebla on a few of the days during the first part of the week. According to the government of Puebla on 25 May the Ministry of Health warned residents to protect themselves from airborne ash with protective clothing and to stay inside when possible due to a reported increase in illnesses relating to ash exposure. By 26 May over one million students were able to return to classrooms.

Rincon de la Vieja - Costa Rica : OVSICORI-UNA reported that phreatic explosions continued at Rincón de la Vieja during 24-30 May. Moderate phreatic events at 1815 and 1830 on 24 May produced voluminous gas-and-steam plumes possibly containing some lake sediments that rose about 2.5 km above the crater rim. Aerial photos from that day showed fairly low lake water levels. The water was a milky gray color and was convecting, partly due to of subaqueous fumaroles. White deposits comprised of altered rocks blanketed the active crater from eruptive activity in recent days. A strong phreatic explosion at 1435 on 25 May produced an ash, gas, and steam plume that drifted NW. Small phreatic events were recorded at 2230 on 25 May and at 0453 and 0704 on 26 May. During a 26 May overflight the lake water level was observed to have significantly dropped compared to 24 May. Phreatic eruptions were recorded at 1357 and 2348 on 26 May and at 0221 and 0632 on 27 May. An energetic eruption at 2135 on 27 May ejected incandescent material and generated a plume mainly comprised of water vapor that rose 3.5-4 km above the crater rim. A significant lahar descended the Pénjamo River and possibly other drainages. On 29 May OVSICORI-UNA noted that the volcano was very active with frequent explosive eruptions. At 0244 an explosion ejected incandescent material and generated a lahar in the Pénjamo River.