The Weekly Volcanic Activity Report: January 30 – February 5, 2019

Posted by Teo Blašković on February 7, 2019. Watchers.news

New activity/unrest was reported for 4 volcanoes between January 30 and February 5, 2019. During the same period, ongoing activity was reported for 10 volcanoes.

New activity/unrest: Barren Island, Andaman Islands (India) | Karangetang, Siau Island (Indonesia) | Merapi, Central Java (Indonesia) | Planchon-Peteroa, Central Chile-Argentina border.

Ongoing activity: Aira, Kyushu (Japan) | Cleveland, Chuginadak Island (USA) | Dukono, Halmahera (Indonesia) | Ebeko, Paramushir Island (Russia) | Fuego, Guatemala | Kuchinoerabujima, Ryukyu Islands (Japan) | Popocatepetl, Mexico | Reventador, Ecuador | Sheveluch, Central Kamchatka (Russia) | Turrialba, Costa Rica.

New activity/unrest

Barren Island, Andaman Islands (India)

12.278°N, 93.858°E, Elevation 354 m

Based on analysis of satellite imagery and wind data, the Darwin VAAC reported that on 26 January ash plumes from Barren Island rose to an altitude of 0.9 km (3,000 ft) a.s.l. and drifted W.

Geological summary: Barren Island, a possession of India in the Andaman Sea about 135 km NE of Port Blair in the Andaman Islands, is the only historically active volcano along the N-S volcanic arc extending between Sumatra and Burma (Myanmar). It is the emergent summit of a volcano that rises from a depth of about 2250 m. The small, uninhabited 3-km-wide island contains a roughly 2-km-wide caldera with walls 250-350 m high. The caldera, which is open to the sea on the west, was created during a major explosive eruption in the late Pleistocene that produced pyroclastic-flow and -surge deposits. Historical eruptions have changed the morphology of the pyroclastic cone in the center of the caldera, and lava flows that fill much of the caldera floor have reached the sea along the western coast.

Karangetang, Siau Island (Indonesia)

2.781°N, 125.407°E, Elevation 1797 m

PVMBG reported that the current eruption at Karangetang began with increased seismicity and thermal anomalies in November 2018. Since then activity was dominated by lava-dome growth, avalanches, and pyroclastic flows. A gray ash plume rose above the summit craters on 30 January. By 2 February ’a’a lava from Kawah Dua (North Crater) had traveled 2.5 km NNW down the Melebuhe River drainage, prompting the evacuation of eight families (about 21 people). A section of the local road was closed, from W of the Batuare River to Kali Melebuhe. According to a news article the flow was 50 m thick in some areas. Seismic signals indicating avalanches sharply increased on 3 February. Lava and pyroclastic flows originated from the Kawah Dua crater, traveling as far as 1 km W down the Sumpihi River drainage, 2 km NW down the Batuare River, and 2.9 km NW down the Malebuhe drainage. BNPB reported that 112 residents (from Niambangeng, Kampung Beba, and Batubulan villages) had evacuated by 1730 on 4 February, and according to a news article the lava crossed the highway at 1800. The lava flow continued to progress and reached the ocean during 5-6 February.

Geological summary: Karangetang (Api Siau) volcano lies at the northern end of the island of Siau, north 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 in the historical record (Catalog of Active Volcanoes of the World: 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 has also produced pyroclastic flows.

Merapi, Central Java (Indonesia)

7.54°S, 110.446°E, Elevation 2910 m

PVMBG reported that during 25-31 January the volume of the lava dome in Merapi’s summit crater was 461,000 cubic meters, relatively unchanged from the previous week. During 0000-2000 on 29 January as many as nine incandescent rockfall events were recorded, with material traveling 200-700 m SE in the Gendol River drainage. Three pyroclastic flows, recorded at 2017, 2053, and 2141, traveled 1.1-1.4 km down the Gendol drainage, and produced minor ashfall in areas E including Boyolali (17 km E), Mriyan (5 km E), and Mojosongo (44 km E). The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to remain outside of the 3-km exclusion zone.

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 2000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequently growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent eruptive 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 during historical time.

Planchon-Peteroa, Central Chile-Argentina border

35.223°S, 70.568°W, Elevation 3977 m

Observatorio Volcanológico de los Andes del Sur (OVDAS)-SERNAGEOMIN and ONEMI reported an increase in ash emissions at Planchón-Peteroa beginning at 1700 on 1 February, with ash plumes rising as high as 2 km and drifting E. This activity was accompanied by the appearance of discrete, very-low-frequency seismic events which were only recorded that day. On 3 February webcams showed gas-and-ash plumes rising to heights less than 2 km. The Alert Level remained at Yellow (the middle level on a three-color scale) for the volcano, and ONEMI maintained Alert Level Yellow for the communities of Molina (66 WNW), Curicó (68 km NW), Romeral (75 km NW), and Teno (68 km NW).

Geological summary: Planchón-Peteroa is an elongated complex volcano along the Chile-Argentina border with several overlapping calderas. Activity began in the Pleistocene with construction of the basaltic-andesite to dacitic Volcán Azufre, followed by formation of basaltic and basaltic-andesite Volcán Planchón, 6 km to the north. About 11,500 years ago, much of Azufre and part of Planchón collapsed, forming the massive Río Teno debris avalanche, which traveled 95 km to reach Chile’s Central Valley. Subsequently, Volcán Planchón II was formed. The youngest volcano, andesitic and basaltic-andesite Volcán Peteroa, consists of scattered vents between Azufre and Planchón. Peteroa has been active into historical time and contains a small steaming crater lake. Historical eruptions from the complex have been dominantly explosive, although lava flows were erupted in 1837 and 1937.

Ongoing activity

Aira, Kyushu (Japan)

31.593°N, 130.657°E, Elevation 1117 m

JMA reported that incandescence from Minamidake crater (at Aira Caldera’s Sakurajima volcano) was visible during 28 January-1 February. An explosion at 1400 on 1 February produced an ash plume that rose 600 m above the crater rim. During a field survey that same day the sulfur dioxide emission rate was high at 3,000 tons/day, an increase from the previous measurement of 1,800 tons/day recorded on 22 January. An explosion at 0228 on 3 February produced an ash plume that rose 1 km and ejected tephra 800-1,100 m from the crater. The Alert Level remained at 3 (on a 5-level scale).

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.

Cleveland, Chuginadak Island (USA)

52.825°N, 169.944°W, Elevation 1730 m

AVO reported that analysis of recent satellite data suggested that the lava dome in Cleveland’s summit crater first observed on 12 January may have stopped growing on 16 January, and since then the center of the dome slowly subsided. Weakly elevated surface temperatures were evident in satellite data during 28 January-4 February. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Geological summary: The beautifully symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited, dumbbell-shaped Chuginadak Island. It lies SE across Carlisle Pass strait from Carlisle volcano and NE across Chuginadak Pass strait from Herbert volcano. Joined to the rest of Chuginadak Island by a low isthmus, Cleveland is the highest of the Islands of the Four Mountains group and is one of the most active of the Aleutian Islands. The native name, Chuginadak, refers to the Aleut goddess of fire, who was thought to reside on the volcano. Numerous large lava flows descend the steep-sided flanks. It is possible that some 18th-to-19th century eruptions attributed to Carlisle should be ascribed to Cleveland (Miller et al., 1998). In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks. This volcano is located within the Aleutian Islands, a UNESCO Biosphere Reserve property.

Dukono, Halmahera (Indonesia)

1.693°N, 127.894°E, Elevation 1229 m

Based on satellite data, wind model data, and notices from PVMBG, the Darwin VAAC reported that on 28 January an ash plume from Dukono rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted SE. During 3-5 February ash plumes rose to 2.1 km (7,000 ft) a.s.l. and drifted S, SW, W, and NW. The Alert Level remained at 2 (on a scale of 1-4), and visitors were 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, Elevation 1103 m

Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 25 January-1 February that sent ash plumes to 2.3 km (7,500 ft) a.s.l. Ash fell in Severo-Kurilsk on 27 January. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

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, Guatemala

14.473°N, 90.88°W, Elevation 3763 m

INSIVUMEH reported that 10-18 explosions per hour were detected at Fuego during 29-31 January. Ash plumes from the explosions rose as high as 1.1 km above the crater rim and drifted E and NE. Ashfall was reported in areas downwind including Alotenango, Antigua Guatemala (18 km NE), and Guatemala City (70 km E). Incandescent material was ejected 300 m high and caused avalanches of material that traveled down Seca (W), Ceniza (SSW), Trinidad (S), and Las Lajas (SE) ravines. During 31January-1 February there were 14-16 explosions recorded per hour, with ash plumes rising as high as 1.1 km and drifting 20-25 km S and SE. Ash fell in the communities of El Rodeo (10 km SSE), El Zapote, Ceilan, and La Rochela. Incandescent material rose 200-400 m high causing avalanches of material to descend the Seca, Taniluyá (SW), Ceniza, Trinidad, Las Lajas, and Honda (E) ravines. Shock wave causing vibration in the communities near the volcano.

Geological summary: Volcán Fuego, one of Central America’s most active volcanoes, is one of three large stratovolcanoes overlooking Guatemala’s former capital, Antigua. The scarp of an older edifice, Meseta, lies between 3763-m-high Fuego and its twin volcano to the north, Acatenango. 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 Acatenango. In contrast to 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.

Kuchinoerabujima, Ryukyu Islands (Japan)

30.443°N, 130.217°E, Elevation 657 m

JMA reported that during 1713-1915 on 29 January an eruption at Kuchinoerabujima’s Shindake Crater produced an ash plume that rose 4 km above the crater rim and drifted E, and a pyroclastic flow. Ash fell in parts of Yakushima. During 30 January-1 February and 3-5 February white plumes rose as high as 600 m. An event that lasted during 1141-1300 on 2 February generated a plume that rose 600 m. The Alert Level remained at 3 (on a scale of 1-5).

Geological summary: A group of young stratovolcanoes forms the eastern end of the irregularly shaped island of Kuchinoerabujima in the northern Ryukyu Islands, 15 km west of Yakushima. The Furudake, Shindake, and Noikeyama cones were erupted from south to north, respectively, forming a composite cone with multiple craters. The youngest cone, centrally-located Shintake, formed after the NW side of Furutake was breached by an explosion. All historical eruptions have occurred from Shintake, although a lava flow from the S flank of Furutake that reached the coast has a very fresh morphology. Frequent explosive eruptions have taken place from Shintake since 1840; the largest of these was in December 1933. Several villages on the 4 x 12 km island are located within a few kilometers of the active crater and have suffered damage from eruptions.

Popocatepetl, Mexico

19.023°N, 98.622°W, Elevation 5393 m

CENAPRED reported that during an overflight of Popocatépetl on 27 January observers noted that the inner crater was 150 m deep and had an unchanged diameter of 300 m. There was no visible lava dome at the bottom of the crater. Each day during 28 January-5 February there were 81-207 steam-and-gas emissions with low ash content. The Alert Level remained at Yellow, Phase Two (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. This volcano is located within the Las Volcanes, a UNESCO Biosphere Reserve property.

Reventador, Ecuador

0.077°S, 77.656°W, Elevation 3562 m

During 28 January-5 February IG reported a high level of seismic activity at Reventador, including explosions, long-period earthquakes, harmonic tremor, and signals indicating emissions. Steam, gas, and ash plumes sometimes rose as high as 1 km above the crater rim and drifted W and NW. Incandescent blocks were observed rolling 600-800 m down the flanks on most days.

Geological summary:  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 Volcán El Reventador stratovolcano rises to 3562 m above the jungles of the western Amazon basin. A 4-km-wide caldera widely breached to the east was formed by edifice collapse and is partially filled by a young, unvegetated stratovolcano that rises about 1300 m above the caldera floor to a height comparable to the caldera rim. It has been the source of numerous lava flows as well as explosive eruptions that were visible from Quito in historical time. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the caldera. The largest historical 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.

Sheveluch, Central Kamchatka (Russia)

56.653°N, 161.36°E, Elevation 3283 m

KVERT reported that during 25 January-1 February Sheveluch’s lava dome continued grow, extruding blocks on the N side, and producing hot avalanches and fumarolic plumes. Video and satellite data recorded gas-and-steam plumes with some ash content rising to 4-4.5 km (13,100-14,800 ft) a.s.l. and drifted 415 km E and W. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Geological summary: The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 km3 volcano is one of Kamchatka’s largest and most active volcanic structures. 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 dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. 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.

Turrialba, Costa Rica

10.025°N, 83.767°W, Elevation 3340 m

OVSICORI-UNA reported that minor, sporadic ash emissions that rose to low heights above Turrialba’s active crater were recorded on most days during 28 January-4 February. An event at 0640 on 1 February produced a taller plume which rose 1.5 km above the crater rim and drifted NW.

OVSICORI-UNA noted that activity had been slowly decreasing in 2019. No volcano-tectonic earthquakes had been recorded, and tremors were decreasing in both energy and duration. The number of low-frequency, volcanic earthquakes (LPs) remained stable, although they had decreasing amplitudes. No explosions had been recorded, and emissions were weak, had short durations, and very dilute ash contents.

Geological summary: Turrialba, the easternmost of Costa Rica’s Holocene volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano located across a broad saddle NE of Irazú volcano overlooking the city of Cartago. The massive edifice covers an area of 500 km2. Three well-defined craters occur at the upper SW end of a broad 800 x 2200 m summit depression that is breached to the NE. Most activity originated from the summit vent complex, but two pyroclastic cones are located on the SW flank. Five major explosive eruptions have occurred during the past 3500 years. A series of explosive eruptions during the 19th century were sometimes accompanied by pyroclastic flows. Fumarolic activity continues at the central and SW summit craters.