The Weekly Volcanic Activity Report: November 9 – 15, 2022

the weekly volcanic activity report

New activity/unrest was reported for 4 volcanoes from November 9 to 15, 2022. During the same period, ongoing activity was reported for 28 volcanoes.

New activity/unrest: Ahyi, Mariana Islands (USA) | Ambae, Vanuatu | Kavachi, Solomon Islands | Kikai, Ryukyu Islands (Japan).

Ongoing activity: Aira, Kyushu (Japan) | Alaid, Kuril Islands (Russia) | Bezymianny, Central Kamchatka (Russia) | Dukono, Halmahera | Ebeko, Paramushir Island (Russia) | Fuego, South-Central Guatemala | Great Sitkin, Andreanof Islands (USA) | Heard, Kerguelen Plateau | Ibu, Halmahera | Karangetang, Sangihe Islands | Karymsky, Eastern Kamchatka (Russia) | Kerinci, Central Sumatra | Kilauea, Hawaiian Islands (USA) | Krakatau, Sunda Strait | Manam, Northeast of New Guinea | Mauna Loa, Hawaiian Islands (USA) | Mayon, Luzon (Philippines) | Merapi, Central Java | Nevado del Ruiz, Colombia | Pavlof, Alaska Peninsula, Alaska | Popocatepetl, Mexico | Reventador, Ecuador | Sabancaya, Peru | Sangay, Ecuador | Santa Maria, Southwestern Guatemala | Semeru, Eastern Java | Sheveluch, Central Kamchatka (Russia) | Suwanosejima, Ryukyu Islands (Japan).

New activity/unrest

Ahyi, Mariana Islands (USA)

20.42°N, 145.03°E | Summit elev. -75 m

On 15 November the USGS reported that hydroacoustic sensors at Wake Island began to record signals in mid-October that are consistent with submarine volcanic activity. A combined analysis of the hydroacoustic signals and seismic data from stations on Guam and Chichijima Island, Japan, suggest the source of this activity is at or near Ahyi seamount. Contrary to initial observations of there being discoloration on the water’s surface, a reanalysis of satellite imagery from 6 November showed no evidence of water discoloration at the ocean surface.

Geological summary: Ahyi seamount is a large conical submarine volcano that rises to within 75 m of the sea surface about 18 km SE of the island of Farallon de Pajaros (Uracas) in the northern Marianas. Water discoloration has been observed there, and in 1979 the crew of a fishing boat felt shocks over the summit area of the seamount, followed by upwelling of sulfur-bearing water. On 24-25 April 2001 an explosive eruption was detected seismically by a station on Rangiroa Atoll, Tuamotu Archipelago. The event was well constrained (+/- 15 km) at a location near the southern base of Ahyi. An eruption in April-May 2014 was detected by NOAA divers, hydroacoustic sensors, and seismic stations.

Ambae, Vanuatu

15.389°S, 167.835°E | Summit elev. 1496 m

On 15 November the Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that at approximately 1300 satellite data showed a large sulfur dioxide emission from Ambae. Seismicity also slightly increased. Residents on the southern and northern parts of the island reported a strong smell of sulfur dioxide gas and heard explosions. The Alert Level remained at 2 (on a scale of 0-5) and the public was warned to stay outside of the Danger Zone, defined as a 2-km radius around the active vents in Lake Voui, and away from drainages during heavy rains.

Geological summary: The island of Ambae, also known as Aoba, is a massive 2,500 km3 basaltic shield that is the most voluminous volcano of the New Hebrides archipelago. A pronounced NE-SW-trending rift zone dotted with scoria cones gives the 16 x 38 km island an elongated form. A broad pyroclastic cone containing three crater lakes (Manaro Ngoru, Voui, and Manaro Lakua) is located at the summit within the youngest of at least two nested calderas, the largest of which is 6 km in diameter. That large central edifice is also called Manaro Voui or Lombenben volcano. Post-caldera explosive eruptions formed the summit craters about 360 years ago. A tuff cone was constructed within Lake Voui (or Vui) about 60 years later. The latest known flank eruption, about 300 years ago, destroyed the population of the Nduindui area near the western coast.

Kavachi, Solomon Islands

8.991°S, 157.979°E | Summit elev. -20 m

Satellite data showed distinct yellow-green discolored water in the vicinity of the submarine Kavachi volcano on 2, 7, 12, and 22 September, 2, 7, 12, 17, and 27 October, and 1, 6, and 11 November.

Geological summary: Named for a sea-god of the Gatokae and Vangunu peoples, Kavachi is one of the most active submarine volcanoes in the SW Pacific, located in the Solomon Islands south of Vangunu Island. Sometimes referred to as Rejo te Kvachi (“Kavachi’s Oven”), this shallow submarine basaltic-to-andesitic volcano has produced ephemeral islands up to 1 km long many times since its first recorded eruption during 1939. Residents of the nearby islands of Vanguna and Nggatokae (Gatokae) reported “fire on the water” prior to 1939, a possible reference to earlier eruptions. The roughly conical edifice rises from water depths of 1.1-1.2 km on the north and greater depths to the SE. Frequent shallow submarine and occasional subaerial eruptions produce phreatomagmatic explosions that eject steam, ash, and incandescent bombs. On a number of occasions lava flows were observed on the ephemeral islands.

Kikai, Ryukyu Islands (Japan)

30.793°N, 130.305°E | Summit elev. 704 m

JMA reported that minor eruptive activity continued to be recorded at Satsuma Iwo-jima, a subaerial part of Kikai’s NW caldera rim, during 7-14 November. White gas-and-steam plumes rose 600 m above the crater rim. Surveillance cameras observed nightly incandescence. The Alert Level remained at 2 (on a 5-level scale), and residents were warned to stay 500 m away from the crater.

Geological summary: Kikai is a mostly submerged, 19-km-wide caldera near the northern end of the Ryukyu Islands south of Kyushu. It was the source of one of the world’s largest Holocene eruptions about 6,300 years ago when rhyolitic pyroclastic flows traveled across the sea for a total distance of 100 km to southern Kyushu, and ashfall reached the northern Japanese island of Hokkaido. The eruption devastated southern and central Kyushu, which remained uninhabited for several centuries. Post-caldera eruptions formed Iodake lava dome and Inamuradake scoria cone, as well as submarine lava domes. Historical eruptions have occurred at or near Satsuma-Iojima (also known as Tokara-Iojima), a small 3 x 6 km island forming part of the NW caldera rim. Showa-Iojima lava dome (also known as Iojima-Shinto), a small island 2 km E of Tokara-Iojima, was formed during submarine eruptions in 1934 and 1935. Mild-to-moderate explosive eruptions have occurred during the past few decades from Iodake, a rhyolitic lava dome at the eastern end of Tokara-Iojima.

Ongoing activity

Aira, Kyushu (Japan)

31.593°N, 130.657°E | Summit elev. 1117 m

JMA reported ongoing eruptive activity at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) and nighttime crater incandescence during 9-15 November. An eruptive event at 2130 on 10 November generated an eruption plume that rose to 1 km above the crater rim. An explosion at 2010 on 15 November produced an ash plume that rose 600 m above the crater and drifted SE. Seven volcanic earthquakes were detected. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.

Geological summary: The Aira caldera in the northern half of Kagoshima Bay contains the post-caldera Sakurajima volcano, one of Japan’s most active. Eruption of the voluminous Ito pyroclastic flow accompanied formation of the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera was formed during the early Holocene in the NE corner of the Aira caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim of Aira caldera and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4850 years ago, after which eruptions took place at Minamidake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu’s largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76.

Alaid, Kuril Islands (Russia)

50.861°N, 155.565°E | Summit elev. 2285 m

KVERT reported that the eruption at Alaid was ongoing during 3-10 November. A weak thermal anomaly was identified in satellite images on 3, 6, and 8-9 November; the volcano was obscured by clouds the other days of the week. On 10 November, KVERT reported that the eruptive activity was gradually decreasing. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Geological summary: The highest and northernmost volcano of the Kuril Islands, 2285-m-high Alaid is a symmetrical stratovolcano when viewed from the north, but has a 1.5-km-wide summit crater that is breached widely to the south. Alaid is the northernmost of a chain of volcanoes constructed west of the main Kuril archipelago. Numerous pyroclastic cones dot the lower flanks of this basaltic to basaltic-andesite volcano, particularly on the NW and SE sides, including an offshore cone formed during the 1933-34 eruption. Strong explosive eruptions have occurred from the summit crater beginning in the 18th century. Reports of eruptions in 1770, 1789, 1821, 1829, 1843, 1848, and 1858 were considered incorrect by Gorshkov (1970). Explosive eruptions in 1790 and 1981 were among the largest in the Kuril Islands during historical time.

Bezymianny, Central Kamchatka (Russia)

55.972°N, 160.595°E | Summit elev. 2882 m

KVERT reported that during 3-10 November a daily thermal anomaly over Bezymianny was identified in satellite images. Strong fumarolic activity was visible, the lava dome continued to grow and was sometimes incandescent at night, and occasional collapses from the dome produced avalanches of hot material. The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Geological summary: The modern Bezymianny, much smaller than its massive neighbors Kamen and Kliuchevskoi on the Kamchatka Peninsula, was formed about 4,700 years ago over a late-Pleistocene lava-dome complex and an ancestral edifice built about 11,000-7,000 years ago. Three periods of intensified activity have occurred during the past 3,000 years. The latest period, which was preceded by a 1,000-year quiescence, began with the dramatic 1955-56 eruption. This eruption, similar to that of St. Helens in 1980, produced a large open crater that was formed by collapse of the summit and an associated lateral blast. Subsequent episodic but ongoing lava-dome growth, accompanied by intermittent explosive activity and pyroclastic flows, has largely filled the 1956 crater.

Dukono, Halmahera

1.693°N, 127.894°E | Summit elev. 1229 m

PVMBG reported that daily white-and-gray gas-and-steam plumes from Dukono rose as high as 800 m above the summit and drifted NE, E, and S during 9-15 November. The Darwin VAAC reported a continuous ash plume that rose to 2.1 km altitude and extended E on 11 November, based on satellite imagery. A discrete ash plume on 14 November rose to 10.7 km altitude and drifted SW. In addition, a strong hotspot and sulfur dioxide signal was observed in satellite imagery. On the same day, a continuous ash plume rose to 2.1-2.4 km altitude and drifted NE, which persisted through 15 November. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Geological summary: Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia’s most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the north-flank cone of Gunung Mamuya. This complex volcano presents a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.

Ebeko, Paramushir Island (Russia)

50.686°N, 156.014°E | Summit elev. 1103 m

KVERT reported that moderate activity at Ebeko was ongoing. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions on 4, 5, 7, and 9 November generated ash plumes that rose to 2.2-3.1 km altitude and drifted in E, NE, and N directions. Ashfall was reported at Severo-Kurilsk on 7 November. A thermal anomaly was identified in satellite images on 4 November; the volcano was covered by clouds the other days of the week. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Geological summary: The flat-topped summit of the central cone of Ebeko volcano, one of the most active in the Kuril Islands, occupies the northern end of Paramushir Island. Three summit craters located along a SSW-NNE line form Ebeko volcano proper, at the northern end of a complex of five volcanic cones. Blocky lava flows extend west from Ebeko and SE from the neighboring Nezametnyi cone. The eastern part of the southern crater contains strong solfataras and a large boiling spring. The central crater is filled by a lake about 20 m deep whose shores are lined with steaming solfataras; the northern crater lies across a narrow, low barrier from the central crater and contains a small, cold crescentic lake. Historical activity, recorded since the late-18th century, has been restricted to small-to-moderate explosive eruptions from the summit craters. Intense fumarolic activity occurs in the summit craters, on the outer flanks of the cone, and in lateral explosion craters.

Fuego, South-Central Guatemala

14.473°N, 90.88°W | Summit elev. 3763 m

INSIVUMEH reported that 5-12 explosions per hour were recorded at Fuego during 9-15 November, generating daily ash plumes that rose as high as 4.5-4.8 km above the crater rim. The ash plumes drifted as far as 10-15 km S, SE, E, NE, SW, and W, causing fine ashfall in areas downwind, including Panimaché I and II (8 km SW), Morelia (9 km SW), La Asunción, La Rochela, Ceilán, San Andrés Osuna, El Rodeo, Ceylén, Santa Sofía (12 km SW), El Porvenir (8 km ENE), Finca Palo Verde, Sangre de Cristo (8 km WSW), and Yepocapa (8 km NW). The explosions generated weak and moderate rumbling that vibrated the roofs and windows of nearby houses. Daily block avalanches descended the Seca (W), Taniluyá (SW), Ceniza (SSW), Trinidad (S), Las Lajas (SE), Honda, Santa Teresa, and El Jute (ESE) drainages, often reaching vegetated areas. The avalanches uplifted fine material 200 m high that dispersed to the S and SW. Explosions ejected incandescent material as high as 400 m above the summit. Weak crater incandescence was observed accompanied by gas-and-steam emissions. On 9 November lahars were generated in the Las Lajas and Ceniza drainages, which carried branches, tree trunks, and blocks 30 cm to 1.5 m in diameter.

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 historical 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.

Great Sitkin, Andreanof Islands (USA)

52.076°N, 176.13°W | Summit elev. 1740 m

AVO reported that slow lava effusion continued at Great Sitkin during 9-15 November and seismicity was low. Satellite images were often cloudy, though elevated surface temperatures were identified on 9, 13, and 15 November. The Volcano Alert Level remained at Watch (the second highest level on a four-level scale) and the Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Geological summary: The Great Sitkin volcano forms much of the northern side of Great Sitkin Island. A younger parasitic volcano capped by a small, 0.8 x 1.2 km ice-filled summit caldera was constructed within a large late-Pleistocene or early Holocene scarp formed by massive edifice failure that truncated an ancestral volcano and produced a submarine debris avalanche. Deposits from this and an older debris avalanche from a source to the south cover a broad area of the ocean floor north of the volcano. The summit lies along the eastern rim of the younger collapse scarp. Deposits from an earlier caldera-forming eruption of unknown age cover the flanks of the island to a depth up to 6 m. The small younger caldera was partially filled by lava domes emplaced in 1945 and 1974, and five small older flank lava domes, two of which lie on the coastline, were constructed along northwest- and NNW-trending lines. Hot springs, mud pots, and fumaroles occur near the head of Big Fox Creek, south of the volcano. Historical eruptions have been recorded since the late-19th century.

Heard, Kerguelen Plateau

53.106°S, 73.513°E | Summit elev. 2745 m

Satellite images of Heard Island’s Big Ben volcano showed thermal anomalies of varying intensity over Mawson Peak (the summit area) and on the NW flank on 9 and 14 November. Weather clouds prevented views of the volcano for the rest of the month. The thermal anomaly on 9 November consisted of three pixels that trended NE-SW from the summit. The activity on 14 November was visible as a larger anomaly over a vent or multiple vents about less than 1 km NW of the peak.

Geological summary: Heard Island on the Kerguelen Plateau in the southern Indian Ocean consists primarily of the emergent portion of two volcanic structures. The large glacier-covered composite basaltic-to-trachytic cone of Big Ben comprises most of the island, and the smaller Mt. Dixon lies at the NW tip of the island across a narrow isthmus. Little is known about the structure of Big Ben because of its extensive ice cover. The historically active Mawson Peak forms the island’s high point and lies within a 5-6 km wide caldera breached to the SW side of Big Ben. Small satellitic scoria cones are mostly located on the northern coast. Several subglacial eruptions have been reported at this isolated volcano, but observations are infrequent and additional activity may have occurred.

Ibu, Halmahera

1.488°N, 127.63°E | Summit elev. 1325 m

PVMBG reported that the eruption at Ibu continued during 9-15 November. Daily white and gray gas-and-steam emissions rose 200-1,000 m above the summit and drifted S, SW, and NW. On 11 November similar emissions rose as high as 1.5 km above the summit and drifted SW and NW. The Darwin VAAC reported that discrete ash emissions rose to 2.1 km altitude and drifted W on 13 November. A possible weak thermal anomaly was observed in satellite imagery. On 15 November a hotspot was visible, accompanied by multiple ash emissions that rose to 2.7 km altitude and drifted NE. The Alert Level remained at a 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater and 3.5 km away on the N side.

Geological summary: The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, has contained several small crater lakes. The 1.2-km-wide outer crater is breached on the N, creating a steep-walled valley. A large cone grew ENE of the summit, and a smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks. The first observed and recorded eruption was a small explosion from the summit crater in 1911. Eruptive activity began again in December 1998, producing a lava dome that eventually covered much of the floor of the inner summit crater along with ongoing explosive ash emissions.

Karangetang, Sangihe Islands

2.781°N, 125.407°E | Summit elev. 1797 m

PVMBG reported that incandescence from Karangetang’s S crater on 9 November and from both the N and S craters on 14 and 15 November. Daily white emissions rose generally 50-150 m above the summit, but sometimes as high as 200 m. The Alert Level remained at 2 (on a scale of 1-4).

Geological summary: Karangetang (Api Siau) volcano lies at the northern end of the island of Siau, about 125 km NNE of the NE-most point of Sulawesi. The stratovolcano contains five summit craters along a N-S line. It is one of Indonesia’s most active volcanoes, with more than 40 eruptions recorded since 1675 and many additional small eruptions that were not documented (Neumann van Padang, 1951). Twentieth-century eruptions have included frequent explosive activity sometimes accompanied by pyroclastic flows and lahars. Lava dome growth has occurred in the summit craters; collapse of lava flow fronts have produced pyroclastic flows.

Karymsky, Eastern Kamchatka (Russia)

54.049°N, 159.443°E | Summit elev. 1513 m

KVERT reported that a thermal anomaly at Karymsky was identified in satellite images on 4 and 9 November. Gas-and-steam emissions persisted. The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Geological summary: Karymsky, the most active volcano of Kamchatka’s eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater.

Kerinci, Central Sumatra

1.697°S, 101.264°E | Summit elev. 3800 m

PVMBG reported that diffuse white-and-brown plumes from Kerinci rose as high as 150 m above the summit and drifted W during 9-15 November. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 3-km exclusion zone.

Geological summary: Gunung Kerinci in central Sumatra forms Indonesia’s highest volcano and is one of the most active in Sumatra. It is capped by an unvegetated young summit cone that was constructed NE of an older crater remnant. There is a deep 600-m-wide summit crater often partially filled by a small crater lake that lies on the NE crater floor, opposite the SW-rim summit. The massive 13 x 25 km wide volcano towers 2400-3300 m above surrounding plains and is elongated in a N-S direction. Frequently active, Kerinci has been the source of numerous moderate explosive eruptions since its first recorded eruption in 1838.

Kilauea, Hawaiian Islands (USA)

19.421°N, 155.287°W | Summit elev. 1222 m

HVO reported that lava continued to effuse from a vent in the lower W wall of Kilauea’s Halema`uma`u Crater during 9-15 November, entering the lava lake and flowing onto the crater floor. On 9 November the sulfur dioxide emission rate was 600 tonnes per day (t/d). The active part of the lake remained at a steady level all week. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.

Geological summary: Kilauea overlaps the E flank of the massive Mauna Loa shield volcano in the island of Hawaii. Eruptions are prominent in Polynesian legends; written documentation since 1820 records frequent summit and flank lava flow eruptions interspersed with periods of long-term lava lake activity at Halemaumau crater in the summit caldera until 1924. The 3 x 5 km caldera was formed in several stages about 1,500 years ago and during the 18th century; eruptions have also originated from the lengthy East and Southwest rift zones, which extend to the ocean in both directions. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1,100 years old; 70% of the surface is younger than 600 years. The long-term eruption from the East rift zone between 1983 and 2018 produced lava flows covering more than 100 km2, destroyed hundreds of houses, and added new coastline.

Krakatau, Sunda Strait

6.102°S, 105.423°E | Summit elev. 155 m

PVMBG reported that multiple ash plumes were visible in webcam images rising from Anak Krakatau during 11 and 14 November. Dense gray ash plumes rose as high as 200 m above the summit and drifted NE at 1047 and at 2343 on 11 November. On 14 November at 0933 ash plumes rose 300 m above the summit and drifted E. Daily white gas-and-steam emissions rose 25-300 m above the summit and drifted generally E and NE. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay at least 5 km away from the crater.

Geological summary: The renowned volcano Krakatau (frequently misstated as Krakatoa) lies in the Sunda Strait between Java and Sumatra. Collapse of the ancestral edifice, perhaps in 416 or 535 CE, formed a 7-km-wide caldera. Remnants of that volcano are preserved in Verlaten and Lang Islands; subsequently Rakata, Danan, and Perbuwatan volcanoes were formed, coalescing to create the pre-1883 Krakatau Island. Caldera collapse during the catastrophic 1883 eruption destroyed Danan and Perbuwatan, and left only a remnant of Rakata. This eruption caused more than 36,000 fatalities, most as a result of tsunamis that swept the adjacent coastlines of Sumatra and Java. Pyroclastic surges traveled 40 km across the Sunda Strait and reached the Sumatra coast. After a quiescence of less than a half century, the post-collapse cone of Anak Krakatau (Child of Krakatau) was constructed within the 1883 caldera at a point between the former cones of Danan and Perbuwatan. Anak Krakatau has been the site of frequent eruptions since 1927.

Manam, Northeast of New Guinea

4.08°S, 145.037°E | Summit elev. 1807 m

The Darwin VAAC reported that on 14 November an ash plume from Manam rose to 2.1 km (7,000 ft) and drifted W based on RVO webcam images.

Geological summary: The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country’s most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical basaltic-andesitic stratovolcano to its lower flanks. These valleys channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Five small satellitic centers are located near the island’s shoreline on the northern, southern, and western sides. Two summit craters are present; both are active, although most observed eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE valley. Frequent eruptions, typically of mild-to-moderate scale, have been recorded since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas.

Mauna Loa, Hawaiian Islands (USA)

19.475°N, 155.608°W | Summit elev. 4170 m

HVO reported continuing unrest at Mauna Loa during 9-15 November. The seismic network detected 27-74 daily small-magnitude (below M 3) earthquakes 2-5 km beneath Mokua’weoweo caldera and 6-8 km beneath the upper NW flank of Mauna Loa. An M 3.6 earthquake occurred NW of the summit on 9 November at 0621. Data from Global Positioning System (GPS) instruments at the summit and flanks showed continuing inflation, though data from tiltmeters at the summit did not show significant surface deformation over the past week. The Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale) and the Aviation Color Code remained at Yellow (the second lowest level on a four-color scale).

Geological summary: Massive Mauna Loa shield volcano rises almost 9 km above the sea floor to form the world’s largest active volcano. Flank eruptions are predominately from the lengthy NE and SW rift zones, and the summit is cut by the Mokuaweoweo caldera, which sits within an older and larger 6 x 8 km caldera. Two of the youngest large debris avalanches documented in Hawaii traveled nearly 100 km from Mauna Loa; the second of the Alika avalanches was emplaced about 105,000 years ago (Moore et al. 1989). Almost 90% of the surface of the basaltic shield volcano is covered by lavas less than 4000 years old (Lockwood and Lipman, 1987). During a 750-year eruptive period beginning about 1500 years ago, a series of voluminous overflows from a summit lava lake covered about one fourth of the volcano’s surface. The ensuing 750-year period, from shortly after the formation of Mokuaweoweo caldera until the present, saw an additional quarter of the volcano covered with lava flows predominately from summit and NW rift zone vents.

Mayon, Luzon (Philippines)

13.257°N, 123.685°E | Summit elev. 2462 m

PHIVOLCS reported that white gas-and-steam plumes from Mayon crept downslope and drifted generally W during 9-15 November. Sulfur dioxide emissions averaged 276 per day on 3 November. Faint crater incandescence was observed at night during 9-12 November. Five volcanic earthquakes were detected during 10-13 November. Electronic Distance Measuring (EDM), precise leveling, continuous GPS, and electronic tilt monitoring data showed that the volcano had been slightly inflated, especially on the NW and SE flanks, since 2020. The Alert Level remained at 2 (on a 0-5 scale) and the public was reminded to stay outside of the 6-km-radius Permanent Danger Zone.

Geological summary: Symmetrical Mayon, which rises above the Albay Gulf NW of Legazpi City, is the most active volcano of the Philippines. The steep upper slopes are capped by a small summit crater. Recorded eruptions since 1616 CE range from Strombolian to basaltic Plinian, with cyclical activity beginning with basaltic eruptions, followed by longer term andesitic lava flows. Eruptions occur predominately from the central conduit and have also produced lava flows that travel far down the flanks. Pyroclastic flows and mudflows have commonly swept down many of the approximately 40 ravines that radiate from the summit and have often damaged populated lowland areas. A violent eruption in 1814 killed more than 1,200 people and devastated several towns.

Merapi, Central Java

7.54°S, 110.446°E | Summit elev. 2910 m

BPPTKG reported that the eruption at Merapi continued during 9-15 November and seismicity remained at high levels. Cloudy often prevented clear visuals of the summit. A seismogram detected a pyroclastic flow at 0905 on 11 November that lasted 135 seconds; it descended 1 km down the Boyong drainage (SW), though webcam images were cloudy. A second pyroclastic flow occurred at 1208 on the same day, lasting 104 seconds and descending 1 km down the Boyong drainage (SW). On 12 November a lava avalanche traveled as far as 800 m down the SW flank. Two lava avalanches were observed descending the SW for 1.5 km on 15 November. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-7 km away from the summit based on location.

Geological summary: Merapi, one of Indonesia’s most active volcanoes, lies in one of the world’s most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequent growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities.

Nevado del Ruiz, Colombia

4.892°N, 75.324°W | Summit elev. 5279 m

Servicio Geológico Colombiano’s (SGC) reported that during 8-14 November seismicity associated with rock fracturing at Nevado del Ruiz increased in number and energy compared to the previous week. Some of the signals were associated with gas-and-ash emissions. The hypocenters were located 0.6-7 km deep. The largest event was an M 3.1 that was recorded at 0225 on 10 November at a depth of 3.6 km below the crater and 2.7 km SW of the crater. The Washington VAAC reported ash plumes that rose to 6.4-7.3 km altitude (21,000-24,000 ft) and drifted S and SE on 11 November, based on satellite and webcam images. During 13-14 November ash plumes rose to 6.7 km altitude (22,000 ft) and drifted NE based on satellite and webcam images. Several low-to-moderate thermal anomalies in Arenas Crater were identified in satellite images. Gas-and-steam plumes (mainly sulfur dioxide) continued to be emitted, rising as high as 1.8 km above the summit on 8 November and drifting NW, SW, SE, and NE. The Alert Level remained at 3 (Yellow; the second lowest level on a four-color scale).

Geological summary: Nevado del Ruiz is a broad, glacier-covered volcano in central Colombia that covers more than 200 km2. Three major edifices, composed of andesitic and dacitic lavas and andesitic pyroclastics, have been constructed since the beginning of the Pleistocene. The modern cone consists of a broad cluster of lava domes built within the caldera of an older edifice. The 1-km-wide, 240-m-deep Arenas crater occupies the summit. The prominent La Olleta pyroclastic cone located on the SW flank may also have been active in historical time. Steep headwalls of massive landslides cut the flanks. Melting of its summit icecap during historical eruptions, which date back to the 16th century, has resulted in devastating lahars, including one in 1985 that was South America’s deadliest eruption.

Pavlof, Alaska Peninsula, Alaska

55.417°N, 161.894°W | Summit elev. 2493 m

AVO reported that a minor eruption at a vent on Pavlof’s upper E flank was ongoing during 9-15 November and nearly continuous seismic tremor was recorded. Multiple explosions were detected almost daily in seismic and infrasound data. Elevated surface temperatures were seen in cloudy satellite images during 10 and 12-15 November. Clear webcam images taken on 12 and 15 November showed a lava flow and ash deposits on the upper flanks, though due to cloudy conditions earlier in the week the timing of these events is uncertain. Nighttime crater incandescence was visible in webcam images on 14 and 15 November. The Volcano Alert Level remained at Watch (the second highest level on a four-level scale) and the Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Geological summary: The most active volcano of the Aleutian arc, Pavlof is a 2519-m-high Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and its twin volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, Pavlof has been frequently active in historical time, typically producing Strombolian to Vulcanian explosive eruptions from the summit vents and occasional lava flows. The active vents lie near the summit on the north and east sides. The largest historical eruption took place in 1911, at the end of a 5-year-long eruptive episode, when a fissure opened on the N flank, ejecting large blocks and issuing lava flows.

Popocatepetl, Mexico

19.023°N, 98.622°W | Summit elev. 5393 m

CENAPRED reported that there were 39-108 steam-and-gas emissions, sometimes containing minor amounts of ash, rising from Popocatépetl each day during 9-15 November. Weather clouds often prevented visual observations of activity. The seismic network recorded daily periods of tremor lasting from 33 minutes to 302 minutes. According to the Washington VAAC, daily ash plumes rose to 5.8-7.6 km altitude (19,000-25,000 ft) and drifted SW, S, SE, and E. Four minor explosions were detected at 1337, 1625, 1629, and 2026 on 10 November. Another four minor explosions were detected at 0141, 1109, 1223, and 1519 on 11 November. Three minor explosions were recorded at 0919, 1933, and 2057 on 12 November. Three minor explosions were detected at 1302 on 13 November, and four minor explosions at 0131, 0615, 1459, and 2330 on 14 November. A minor explosion was also detected at 0710 on 15 November. A total of five volcano-tectonic earthquakes were recorded on 11 and 12 November. Light ashfall was reported in Tochimilco, Puebla on 10 November. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale).

Geological summary: Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, rises 70 km SE of Mexico City to form North America’s 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 400 x 600 m wide crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas to the south. The modern volcano was constructed south of the late-Pleistocene to Holocene El Fraile cone. Three major Plinian eruptions, the most recent of which took place about 800 CE, have occurred since the mid-Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since Pre-Columbian time.

Reventador, Ecuador

0.077°S, 77.656°W | Summit elev. 3562 m

IG described the ongoing eruption at Reventador as moderate during 9-15 November. Daily seismicity was characterized by 18-47 explosions, 22-45 long-period earthquakes, and 2-18 signals that indicated emissions. During 9-12 November there were also 1-4 periods of daily harmonic tremor. Gas, steam, and ash plumes, observed almost daily with webcams or reported by the Washington VAAC, rose as high as 1.3 km above the summit and drifted S, W, SW, N, and NW. Crater incandescence was occasionally visible at night and the lava flow on the NE flank was active. Sulfur dioxide emissions averaged 22, 20.2, and 174.9 tons per day on 9, 11, and 12 November, respectively. An incandescent avalanche was visible on the N flank during the night of 9 November; by 10 November it had traveled to 800 m below the crater.

Geological summary: Volcán El Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well east of the principal volcanic axis. The forested, dominantly andesitic stratovolcano has 4-km-wide avalanche scarp open to the E formed by edifice collapse. A young, unvegetated, cone rises from the amphitheater floor about 1,300 m to a height comparable to the rim. It has been the source of numerous lava flows as well as explosive eruptions visible from Quito, about 90 km ESE. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the scarp. The largest recorded eruption took place in 2002, producing a 17-km-high eruption column, pyroclastic flows that traveled up to 8 km, and lava flows from summit and flank vents.

Sabancaya, Peru

15.787°S, 71.857°W | Summit elev. 5960 m

Instituto Geofísico del Perú (IGP) reported moderate levels of activity at Sabancaya during 7-13 November with a daily average of 33 explosions. Gas-and-ash plumes rose as high as 3 km above the summit and drifted S, E, and NE. As many as five thermal anomalies originating from the lava dome in the summit crater were identified in satellite data. Minor inflation continued to be detected near Hualca Hualca (4 km N). The Alert Level remained at Orange (the second highest level on a four-color scale) and the public were warned to stay outside of a 12-km radius. Geological summary: Sabancaya, located in the saddle NE of Ampato and SE of Hualca Hualca volcanoes, is the youngest of these volcanic centers and the only one to have erupted in historical time. The oldest of the three, Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene age. The name Sabancaya (meaning “tongue of fire” in the Quechua language) first appeared in records in 1595 CE, suggesting activity prior to that date. Holocene activity has consisted of Plinian eruptions followed by emission of voluminous andesitic and dacitic lava flows, which form an extensive apron around the volcano on all sides but the south. Records of historical eruptions date back to 1750.

Sangay, Ecuador

2.005°S, 78.341°W | Summit elev. 5286 m

IG reported a high level of activity at Sangay during 9-15 November, which included daily explosions, volcanic tremor, and gas-and-steam emissions. Incandescence at the summit was periodically visible at night. Daily ash-and-gas plumes were identified in either or both IG webcam images and satellite images according to the Washington VAAC. Plumes generally rose as high as 1.8 m above the volcano and drifted SW, W, S, N, and NW. Moderate ashfall was reported in Zuñac on 9 November. During 10-14 November an incandescent avalanche was observed descending the SE flank during the night.

Geological summary: The isolated Sangay volcano, located east of the Andean crest, is the southernmost of Ecuador’s volcanoes and its most active. The steep-sided, glacier-covered, dominantly andesitic volcano grew within the open calderas of two previous edifices which were destroyed by collapse to the east, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. It towers above the tropical jungle on the east side; on the other sides flat plains of ash have been eroded by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an eruption was in 1628. Almost continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The almost constant activity has caused frequent changes to the morphology of the summit crater complex.

Santa Maria, Southwestern Guatemala

14.757°N, 91.552°W | Summit elev. 3745 m

INSIVUMEH reported that nighttime incandescence was observed in the crater of Santa María’s Santiaguito lava-dome complex during 9-15 November. The lava flows continued to descend the San Isidro and El Tambor drainages, as well as the S flank. Block-and-ash avalanches from the dome, and from the middle and front of the lava flows, descended the W, SW, and S flanks. Fine ash fell on the perimeter of the volcano. Moderate gas-and-steam plumes rose as high as 500-700 m above the dome complex that extended 3-6 km E, SE, S, SW, and W. Geological summary: Symmetrical, forest-covered Santa María volcano is part of a chain of large stratovolcanoes that rise above the Pacific coastal plain of Guatemala. The sharp-topped, conical profile is cut on the SW flank by a 1.5-km-wide crater. The oval-shaped crater extends from just below the summit to the lower flank, and was formed during a catastrophic eruption in 1902. The renowned Plinian eruption of 1902 that devastated much of SW Guatemala followed a long repose period after construction of the large basaltic-andesite stratovolcano. The massive dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four vents, with activity progressing W towards the most recent, Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Semeru, Eastern Java

8.108°S, 112.922°E | Summit elev. 3657 m

PVMBG reported that the eruption at Semeru continued during 9-15 November. A pyroclastic flow was observed descending the SE flank as far as 4.5 km at 1550 on 9 November. The event also generated a white-gray ash plume that rose 1.5 km above the summit and drifted NE. On 14 November an ash plume rose to 3.9 km altitude and drifted SW, according to the Darwin VAAC. White gas-and-steam emissions rose 100-1,000 m above the summit and drifted N, NE, S, and SW. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 5 km away from the summit, and 500 m from Kobokan drainages within 17 km of the summit, along with other drainages originating on Semeru, including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards.

Geological summary: Semeru, the highest volcano on Java, and one of its most active, lies at the southern end of a volcanic massif extending north to the Tengger caldera. The steep-sided volcano, also referred to as Mahameru (Great Mountain), rises above coastal plains to the south. Gunung Semeru was constructed south of the overlapping Ajek-ajek and Jambangan calderas. A line of lake-filled maars was constructed along a N-S trend cutting through the summit, and cinder cones and lava domes occupy the eastern and NE flanks. Summit topography is complicated by the shifting of craters from NW to SE. Frequent 19th and 20th century eruptions were dominated by small-to-moderate explosions from the summit crater, with occasional lava flows and larger explosive eruptions accompanied by pyroclastic flows that have reached the lower flanks of the volcano.

Sheveluch, Central Kamchatka (Russia)

56.653°N, 161.36°E | Summit elev. 3283 m

KVERT reported that the ongoing eruption at Sheveluch during 3-10 November was generally characterized by explosions, hot avalanches, lava-dome extrusion, and strong fumarolic activity. A daily thermal anomaly was identified in satellite images. Collapses generated hot avalanches and ash plumes that drifted 400 km N, NE, and E during 5-7 November. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Geological summary: The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1,300 km3 andesitic volcano is one of Kamchatka’s largest and most active volcanic structures, with at least 60 large eruptions during the Holocene. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes occur on its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large open caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Suwanosejima, Ryukyu Islands (Japan)

29.638°N, 129.714°E | Summit elev. 796 m

JMA reported that the eruption at Suwanosejima’s Ontake Crater continued during 9-15 November and crater incandescence was visible nightly. An explosion at 2238 on 11 November produced an eruption plume that rose 1.6 km above the crater rim. Ash plumes during 15 November rose 1-1.3 km above the crater and drifted SE. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.

Geological summary: The 8-km-long island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. The summit is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. One of Japan’s most frequently active volcanoes, it was in a state of intermittent Strombolian activity from Otake, the NE summit crater, between 1949 and 1996, after which periods of inactivity lengthened. The largest recorded eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed, forming a large debris avalanche and creating the open Sakuchi caldera, which extends to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island.

Reference:

Smithsonian / US Geological Survey Weekly Volcanic Activity Report – November 9 – 15, 2022 – Managing Editor: Sally Kuhn Sennert

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