Ongoing activity was observed at 15 volcanoes from July 23 – 29, 2014.
Ongoing activity: Aira, Kyushu (Japan) | Bezymianny, Central Kamchatka (Russia) | Fuego, Guatemala | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaiian Islands (USA) | Pacaya, Guatemala | Popocatepetl, Mexico | Reventador, Ecuador | San Miguel, El Salvador | Santa Maria, Guatemala | Shishaldin, Fox Islands (USA) | Shiveluch, Central Kamchatka (Russia) | Tungurahua, Ecuador | Ubinas, Peru | Zhupanovsky, Eastern Kamchatka (Russia)
The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 23:00 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail.
Aira, Kyushu (Japan)
31.593°N, 130.657°E, Summit elev. 1117 m
JMA reported three explosive eruptions from Showa Crater at Aira Caldera’s Sakurajima volcano on 22, 25, and 27 July that ejected ballistics 300-800 m away. In general, the eruptions were accompanied by volcanic earthquakes and increasing volcanic tremor. On 28 July a very small eruption cloud rose 200 m above Minami-Dake Crater. The Tokyo VAAC reported that on 23, 25, and 27 July plumes rose to an altitude of 1.5-2.5 km (5,000-8,000 ft) a.s.l. and drifted E and NE. The Alert Level remained at 3 (on a scale of 1-5).
Geologic 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.
Bezymianny, Central Kamchatka (Russia)
55.978°N, 160.587°E, Summit elev. 2882 m
KVERT reported that during 19-25 July weak seismicity and moderate fumerolic activity were observed at Bezymianny. Satellite data showed a thermal anomaly over the volcano all week. On 17 July the Aviation Color Code was lowered to Yellow.
Geologic summary: Prior to its noted 1955-56 eruption, Bezymianny volcano had been considered extinct. The modern Bezymianny, much smaller in size than its massive neighbors Kamen and Kliuchevskoi, was formed about 4700 years ago over a late-Pleistocene lava-dome complex and an ancestral volcano that was built between about 11,000-7000 years ago. Three periods of intensified activity have occurred during the past 3000 years. The latest period, which was preceded by a 1000-year quiescence, began with the dramatic 1955-56 eruption. This eruption, similar to that of Mount St. Helens in 1980, produced a large horseshoe-shaped 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.
14.473°N, 90.88°W, Summit elev. 3763 m
During 23-29 July INSIVUMEH reported moderate to strong explosions at Fuego, with incandescent blocks being expelled 100-200 m above the crater accompanied by moderate to dark gray ash 400-600 m above the crater that drifted NW, W, and SW. On most days avalanches moved down the flanks. Columns, described as containing ash on 24 and 28 July, rose 4-4.6 km (13,100-15,100 ft) a.s.l. and drifted 8-12 km NE, NW, W, and SW. A weak white fumarolic plume rose above Fuego’s summit crater on 27-28 July. During 26-27 July, rumbling was heard up to 15 km away. Ashfall was reported most days in nearby areas, including the Santa Teresa, Taniluya, Ceniza, and Trinidad drainages, and at the Observatory, Morelia, Hagia Sophia, Ingenio los Tarros, Panimaché, Santa Sofia, Yepocapa, and Finca La Conchita.
Geologic 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.
Karymsky, Eastern Kamchatka (Russia)
54.05°N, 159.45°E, Summit elev. 1536 m
KVERT reported weak to moderate seismic activity at Karymsky, indicating that Strombolian activity continued during 19-25 July. Satellite views were obscured by clouds or the imagery showed no activity. On 24 July the Aviation Color Code was lowered to Yellow.
Geologic 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, which is located immediately south of Karymsky volcano. The caldera enclosing Karymsky volcano formed about 7600-7700 radiocarbon years ago; construction of the Karymsky 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.
Kilauea, Hawaiian Islands (USA)
19.421°N, 155.287°W, Summit elev. 1222 m
During 23-29 July HVO reported that the circulating lava lake occasionally rose and fell in the deep pit within Kilauea's Halema`uma`u Crater. Gas emissions remained elevated. The plume from the vent continued to deposit variable amounts of ash, spatter, and Pele's hair onto nearby areas; smaller particles may have been dropped several kilometers away. On 24 July a small explosion triggered by rockfalls from the southeast crater wall sent spatter onto the closed tourist overlook at Halema`uma`u; small rockfalls also disturbed the lava lake surface on 27 July.
Lava flows fed from a vent on Pu`u `O`o's northeast flank continued to advance slowly NE as two lobes that reached 2.4 km from the vent on 25 July. Lava was at or near the surface within the four pits on the crater floor and a small lava flow erupted from the southern pit during the night of 25-26 July. On 28 July there were a few small collapses around the edge of Pu`u `O`o's crater.
Geologic summary: Kilauea volcano, which overlaps the east flank of the massive Mauna Loa shield volcano, has been Hawaii's most active volcano during historical time. Eruptions of Kilauea are prominent in Polynesian legends; written documentation extending back to only 1820 records frequent summit and flank lava flow eruptions that were interspersed with periods of long-term lava lake activity that lasted until 1924 at Halemaumau crater, within the summit caldera. The 3 x 5 km caldera was formed in several stages about 1500 years ago and during the 18th century; eruptions have also originated from the lengthy East and SW rift zones, which extend to the sea on both sides of the volcano. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 sq km, destroying nearly 200 houses and adding new coastline to the island.
14.381°N, 90.601°W, Summit elev. 2552 m
INSIVUMEH reported that during 23-29 July white to white-and-blue fumarolic plumes rose 50-75 m above Mackenney Crater at Pacaya and drifted up to 800 m NW, W, SW, and S.
Geologic summary: Eruptions from Pacaya, one of Guatemala's most active volcanoes, are frequently visible from Guatemala City, the nation's capital. Pacaya is a complex basaltic volcano constructed just outside the southern topographic rim of the 14 x 16 km Pleistocene Amatitlán caldera. A cluster of dacitic lava domes occupies the southern caldera floor. The post-caldera Pacaya massif includes the ancestral Pacaya Viejo and Cerro Grande stratovolcanoes and the currently active Mackenney stratovolcano. Collapse of Pacaya Viejo volcano between 600 and 1500 years ago produced a debris-avalanche deposit that extends 25 km onto the Pacific coastal plain and left an arcuate somma rim inside which the modern Pacaya volcano (Mackenney cone) grew. A subsidiary crater, Cerro Chino, was constructed on the NW somma rim and was last active in the 19th century. During the past several decades, activity at Pacaya has consisted of frequent strombolian eruptions with intermittent lava flow extrusion that has partially filled in the caldera moat and armored the flanks of Mackenney cone, punctuated by occasional larger explosive eruptions that partially destroy the summit of the growing young stratovolcano.
19.023°N, 98.622°W, Summit elev. 5426 m
CENAPRED reported that during 23-29 July steam and gas emission rose 200-500 m above Popocatépetl’s crater and drifted NW, W, SW, and E. On 29 July, emissions were accompanied by 30 minutes of tremor. Slight nighttime incandescence was observed. The Alert Level remained at Yellow, Phase Two.
Geologic summary: Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5426 m 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 from Popocatépetl 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 precolumbian time.
0.077°S, 77.656°W, Summit elev. 3562 m
IG reported moderate seismicity including explosions, long-period earthquakes, harmonic tremor, and tremor, though cloud cover mostly prevented observations of Reventador during 23-29 July. On 23 July IG reported that a column rose to 1 km above the crater and on 24 July reported strong roaring and a plume that drifted NW. On 27 July an emission was seen in satellite imagery.
Geologic 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.
San Miguel, El Salvador
13.434°N, 88.269°W, Summit elev. 2130 m
SNET reported seismic activity at San Miguel during 23-29 July. On 24 July an ash cloud from a small explosion rose 400 m and drifted SW and deposited small amounts of ash in La Morita, Piedra Azul, and San Rafael East. Ash clouds from small explosions on 27-28 July deposited small amounts of ash to the SW in the La Morita Townships of La Piedrita and La Ceiba.
Geologic summary: The symmetrical cone of San Miguel volcano, one of the most active in El Salvador, rises from near sea level to form one of the country's most prominent landmarks. The unvegetated summit of the 2130-m-high volcano rises above slopes draped with coffee plantations. A broad, deep crater complex that has been frequently modified by historical eruptions (recorded since the early 16th century) caps the truncated summit of the towering volcano, which is also known locally as Chaparrastique. Radial fissures on the flanks of the basaltic-andesitic volcano have fed a series of historical lava flows, including several erupted during the 17th-19th centuries that reached beyond the base of the volcano on the north, NE, and SE sides. The SE-flank lava flows are the largest and form broad, sparsely vegetated lava fields crossed by highways and a railroad skirting the base of the volcano. The location of flank vents has migrated higher on the edifice during historical time, and the most recent activity has consisted of minor ash eruptions from the summit crater.
Santa Maria, Guatemala
14.756°N, 91.552°W, Summit elev. 3772 m
INSIVUMEH reported that on most days during 23-29 July the active lava dome of Santiaguito was visibly degassing and generating plumes, noting an ashexplosion on 26 July rising up to 3 km (9,800 ft) a.s.l. that drifted W. On 28 July thin ash columns rose 3.2 km (10,500 ft) a.s.l. that drifted SW. On most days,fumarolic columns reached 2.7-2.8 km (8,800-9,200 ft) a.s.l. that drifted SW and weak to strong avalanches flowed towards Canyon Nima River I.
Geologic summary: Symmetrical, forest-covered Santa María volcano is one of the most prominent of a chain of large stratovolcanoes that rises dramatically above the Pacific coastal plain of Guatemala. The 3772-m-high stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a large, 1.5-km-wide crater. The oval-shaped crater extends from just below the summit of Volcán Santa María 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 westward-younging vents, the most recent of which is Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars.
Shishaldin, Fox Islands (USA)
54.756°N, 163.97°W, Summit elev. 2857 m
AVO reported that during 23-29 July low-level eruptive activity continued at Shishaldin volcano. Elevated surface temperatures at the summit were detected daily from satellite data. On 26 July satellite and web camera images showed trace dustings of ash over fresh snow in the immediate vicinity of the crater. Web camera images showed short dark streaks of possible debris flow deposits extending from the summit crater on the southeast flank, possibly the result of the melting of snow and ice near the summit due to the increased temperatures in the vicinity of the crater. Web camera and satellite images were mostly obscured due to clouds other days. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.
Geologic summary: The beautifully symmetrical volcano of Shishaldin is the highest and one of the most active volcanoes of the Aleutian Islands. The 2857-m-high, glacier-covered volcano is the westernmost of three large stratovolcanoes along an E-W line in the eastern half of Unimak Island. The Aleuts named the volcano Sisquk, meaning "mountain which points the way when I am lost." A steady steam plume rises from its small summit crater. Constructed atop an older glacially dissected volcano, it is Holocene in age and largely basaltic in composition. Remnants of an older ancestral volcano are exposed on the west and NE sides at 1500-1800 m elevation. There are over two dozen pyroclastic cones on its NW flank, which is blanketed by massive aa lava flows. Frequent explosive activity, primarily consisting of strombolian ash eruptions from the small summit crater, but sometimes producing lava flows, has been recorded since the 18th century.
Shiveluch, Central Kamchatka (Russia)
56.653°N, 161.36°E, Summit elev. 3283 m
KVERT reported that during 19-26 July lava-dome extrusion onto Shiveluch’s SE flank was accompanied by moderate ash explosions, incandescence of the dome summit, hot avalanches, and fumarolic activity. Satellite data showed a thermal anomaly over the volcano, but satellite images were obscured by clouds or showed the volcano was quiet over the past week. The Aviation Color Code remained at Orange.
Geologic summary: The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 cu km Shiveluch 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 of Shiveluch 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.
1.467°S, 78.442°W, Summit elev. 5023 m
During 23-27 July IG reported that Tungurahua had low levels of seismicity and cloudy conditions with small steam columns observed on 26 July. On 28 July the IG reported an increase in seismic activity and a small explosion with an ash plume that rose 1 km above the crater that moved NW. Ashfall was reported in the Chontapamba area. On 29 July seismicity was moderate and clouds obscured views of the volcano.
Geologic summary: Tungurahua, a steep-sided andesitic-dacitic stratovolcano that towers more than 3 km above its northern base, is one of Ecuador's most active volcanoes. Three major volcanic edifices have been sequentially constructed since the mid-Pleistocene over a basement of metamorphic rocks. Tungurahua II was built within the past 14,000 years following the collapse of the initial edifice. Tungurahua II itself collapsed about 3000 years ago and produced a large debris-avalanche deposit and a horseshoe-shaped caldera open to the west, inside which the modern glacier-capped stratovolcano (Tungurahua III) was constructed. Historical eruptions have all originated from the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. Prior to a long-term eruption beginning in 1999 that caused the temporary evacuation of the city of Baños at the foot of the volcano, the last major eruption had occurred from 1916 to 1918, although minor activity continued until 1925.
16.355°S, 70.903°W, Summit elev. 5672 m
On 23 July the Buenos Aires VAAC reported a weak emission of light ash. During 23-25 July INGEMMET and IGP reported that seismicity at Ubinas has decreased. On 23-24 July mild gas-and-ash emissions rose 200-550 m above the summit and drifted E and NE. On 25 July there were no explosions, but minor gas and ash emissions drifted E.
Geologic summary: A small, 1.4-km-wide caldera cuts the top of Ubinas, Peru's most active volcano, giving it a truncated appearance. Ubinas is the northernmost of three young volcanoes located along a regional structural lineament about 50 km behind the main volcanic front of Perú. The growth and destruction of Ubinas I volcano was followed by construction of Ubinas II volcano beginning in the mid-Pleistocene. The upper slopes of the andesitic-to-rhyolitic Ubinas II stratovolcano are composed primarily of andesitic and trachyandesitic lava flows and steepen to nearly 45 degrees. The steep-walled, 150-m-deep summit caldera contains an ash cone with a 500-m-wide funnel-shaped vent that is 200 m deep. Debris-avalanche deposits from the collapse of the SE flank of Ubinas about 3700 years ago extend 10 km from the volcano. Widespread plinian pumice-fall deposits from Ubinas include one of Holocene age about 1000 years ago. Holocene lava flows are visible on the volcano's flanks, but historical activity, documented since the 16th century, has consisted of intermittent minor-to-moderate explosive eruptions.
Zhupanovsky, Eastern Kamchatka (Russia)
53.59°N, 159.147°E, Summit elev. 2958 m
KVERT reported that during 19-25 July the moderate explosive eruption continued at Zhupanovsky. On 18 and 21 July satellite data showed ash plumes that rose to 4 km (13,100 ft) a.s.l. and extended about 30 and 70 km NE, respectively. A thermal anomaly was observed over the volcano on 19 and 21 July. TokyoVAAC reported an ash plume on 27 July that rose to 8.5 km (28,000 ft) a.s.l. and drifted N.
Geologic summary: The Zhupanovsky volcanic massif consists of four overlapping stratovolcanoes along a WNW-trending ridge. The elongated volcanic complex was constructed within a Pliocene-early Pleistocene caldera whose rim is exposed only on the eastern side. Three of the stratovolcanoes were built during the Pleistocene, the fourth is Holocene in age and was the source of all of Zhupanovsky's historical eruptions. An early Holocene stage of frequent moderate and weak eruptions from 7000 to 5000 years before present (BP) was succeeded by a period of infrequent larger eruptions that produced pyroclastic flows. The last major eruption took place about 800-900 years BP. Historical eruptions have consisted of relatively minor explosions from the third cone.
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