Fuego is one of three large stratovolcanoes overlooking the city of Antigua, Guatemala. It has been erupting since January 2002, with observed eruptions dating back to 1531 CE. Typical activity is characterized by ashfall, pyroclastic flows, lava flows, and lahars. Frequent explosions with ash emissions, block avalanches, and lava flows have been reported since 2018. More recently, activity has been characterized by multiple explosions and ash plumes each day, ashfall, block avalanches, and pyroclastic flows (BGVN 48:09). This report describes similar activity of explosions, gas-and-ash plumes, and block avalanches during August through November 2023 based on daily reports from the Instituto Nacional de Sismologia, Vulcanología, Meteorología e Hidrologia (INSIVUMEH) and various satellite data.

Multiple explosions each day were reported during August through November 2023 that produced ash plumes that rose to 4.9 km altitude and drifted as far as 30 km in different directions. The explosions also caused rumbling sounds of varying intensities, with shock waves that vibrated the roofs and windows of homes near the volcano. Incandescent pulses of material rose as high as 350 m above the crater, accompanied by block avalanches that descended multiple drainages. Light ashfall was often reported in nearby communities (table 29). MIROVA (Middle InfraRed Observation of Volcanic Activity) analysis of MODIS satellite data showed intermittent low-to-moderate power thermal activity during the reporting period (figure 175). A total of seven MODVOLC thermal alerts were issued on 11 August, 1, 13, and 23 September, and 10, 17, and 18 November. On clear weather days thermal anomalies were also visible in infrared satellite imagery in the summit crater (figure 176).

Table 29. Activity at Fuego during August through November 2023 included multiple explosions every hour. Ash emissions rose as high as 4.9 km altitude and drifted in multiple directions as far as 30 km, causing ashfall in many communities around the volcano. Data from daily INSIVUMEH reports.

Figure 175. Intermittent low-to-moderate power thermal activity was detected at Fuego during August through November 2023, based on this MIROVA graph (Log Radiative Power). Courtesy of MIROVA.

Figure 176. Infrared (bands B12, B11, B4) satellite images showing a persistent thermal anomaly at the summit crater of Fuego on 27 August 2023 (top left), 1 September 2023 (top right), 16 October 2023 (bottom left), and 30 November 2023 (bottom right). Courtesy of Copernicus Browser.

Activity during August consisted of 1-11 explosions each day, which generated ash plumes that rose to 4-4.8 km altitude and drifted 8-30 km W, NW, SW, N, NE, and E. Fine ashfall was reported in Panimaché I and II (8 km SW), Morelia (9 km SW), Santa Sofía (12 km SW), Yepocapa (8 km NW), Finca Palo Verde (10 km WSW), Sangre de Cristo (8 km WSW), Acatenango (8 km E), Aldeas, El Porvenir (11 km SW), La Reunión (7 km SE), San Miguel Dueñas (10 km NE), Ciudad Vieja (13.5 km NE), Antigua (18 km NE), Quisaché (8 km NW), and El Sendero. The explosions sometimes ejected incandescent material 50-250 m above the crater and generated weak-to-moderate block avalanches that descended the Santa Teresa (W), Seca (W), Taniluyá (SW), Ceniza (SSW), Las Lajas (SE), El Jute (ESE), Trinidad (S), and Honda (E) drainages. Lahars were reported in the Ceniza drainage on 8-9, 16, 26-27, and 29 August, carrying fine and hot volcanic material, branches, tree trunks, and blocks measured 30 cm up to 1.5 m in diameter. Similar lahars affected the Las Lajas, El Jute, Seca, and El Mineral (W) drainages on 27 August.

Daily explosions ranged from 3-11 during September, which produced ash plumes that rose to 4-4.8 km altitude and drifted 10-30 km SW, W, NW, S, and SE. The explosions were accompanied by block avalanches that affected the Seca, Taniluyá, Ceniza, Las Lajas, Honda, Santa Teresa, Trinidad, and El Jute drainages and occasional incandescent ejecta rose 50-300 m above the crater. Fine ashfall was reported in Panimaché I and II, Morelia, Palo Verde, Sangre de Cristo, Yepocapa, El Porvenir, Aldeas, Santa Sofía, Montellano, El Socorro, La Rochela (8 km SSW), La Asunción (12 km SW), San Andrés Osuna (11 km SSW), Guadalupe, La Trinidad (S). Lahars triggered by rainfall were detected in the Ceniza drainage on 3-4, 8, 13-14, 17, 20-21, 24, 26, 29-30 September, which carried fine and hot volcanic material, branches, tree trunks, and blocks measuring 30 cm to 3 m in diameter. Similar lahars were also detected in the Seca, El Mineral, Las Lajas, and El Jute drainages on 27 September.

There were 2-10 explosions recorded each day during October, which produced ash plumes that rose to 4-4.9 km altitude and drifted 10-30 km W, SW, S, NW, N, NE, and SE. Incandescent pulses of material rose 50-350 m above the crater. Many of the explosions generated avalanches that descended the Ceniza, Santa Teresa, Taniluyá, Trinidad, Seca, El Jute, Las Lajas, and Honda drainages. Ashfall was reported in Aldeas, Panimaché I and II, Morelia, Santa Sofía, El Porvenir, Sangre de Cristo, Yepocapa, Yucales, Palo Verde, Acatenango, Patzicía, Alotenango, La Soledad (11 km N), El Campamento, La Rochela, Las Palmas, and Quisaché. Lahars continued to be observed on 2-5, 7, 9, 11, and 21-22 October, carrying fine and hot volcanic material, branches, tree trunks, and blocks measuring 30 cm to 3 m in diameter. Similar lahars were also reported in the Seca and Las Lajas drainage on 2 October and in the Las Lajas drainage on 4 October. On 4 October lahars overflowed the Ceniza drainage toward the Zarco and Mazate drainages, which flow from Las Palmas toward the center of Siquinalá, resulting from intense rainfall and the large volume of pyroclastic material in the upper part of the drainage. On 9 October a lahar was reported in the Seca and Las Lajas drainages, and lahars in the Las Lajas and El Jute drainages were reported on 11 October. A lahar on 22 October was observed in the Seca drainage, which interrupted transportation between San Pedro Yepocapa and the communities in Santa Sofía, Morelia, and Panimaché.

During November, 1-10 daily explosions were recorded, sometimes accompanied by avalanches, rumbling sounds, and shock waves. Gas-and-ash plumes rose 4.5-4.8 km altitude and extended 10-30 km W, SW, S, E, SE, NW, and N. Incandescent pulses of material rose 50-200 m above the crater. Fine ashfall was reported in Panimaché I and II, Morelia, Yepocapa, El Porvenir, Palo Verde, Santa Sofía, Aldeas, Sangre de Cristo, Yucales, La Rochela, San Andrés Osuna, Ceilán (9 km S), Quisaché, Acatenango, La Soledad. Avalanches of material descended the Seca, Taniluyá, Ceniza, Las Lajas, El Jute, Honda, Santa Teresa, and Trinidad drainages.

Geological Summary. Volcán Fuego, one of Central America's most active volcanoes, is also one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between Fuego and Acatenango to the north. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at the mostly andesitic Acatenango. Eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows.

Information Contacts: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia e Hydrologia (INSIVUMEH), Unit of Volcanology, Geologic Department of Investigation and Services, 7a Av. 14-57, Zona 13, Guatemala City, Guatemala (URL: http://www.insivumeh.gob.gt/ ); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Copernicus Browser, Copernicus Data Space Ecosystem, European Space Agency (URL: https://dataspace.copernicus.eu/browser/).