New activity/unrest was observed at 2 volcanoes from August 13 - August 19, 2014. Ongoing activity was reported for 18 volcanoes.
New activity/unrest: Bardarbunga, Iceland, Mayon, Luzon (Philippines)
Ongoing activity: Aira, Kyushu (Japan) | Etna, Sicily (Italy) | Fuego, Guatemala | Kilauea, Hawaiian Islands (USA) | Kuchinoerabujima, Ryukyu Islands (Japan) | Kusatsu-Shiranesan, Honshu (Japan) | Pacaya, Guatemala | Popocatepetl, Mexico | Reventador, Ecuador | Sabancaya, Peru | San Miguel, El Salvador | Santa Maria, Guatemala | Shishaldin, Fox Islands (USA) | Shiveluch, Central Kamchatka (Russia) | Stromboli, Aeolian Islands (Italy) | 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.
64.63°N, 17.53°W, Summit elev. 2009 m
During 13-19 August the Icelandic Met Office reported increased seismic activity at Bárdarbunga volcano. On 16 August more than 200 earthquakes were reported under the NW Vatnajökull ice cap, and GPS stations have shown an increasing signal upward and away from the volcano since early June 2014. On 16 August the Aviation Color code was increased to Yellow. On 18 August the Icelandic Met Office reported an earthquake swarm to the E and another to the N of Bárdarbunga. A M4 earthquake was recorded that was the strongest in the region since 1996. By 18 August there had been 2,600 earthquakes detected at the volcano; earthquake locations from N and E swarms had been migrating NE, but in the evening activity of the N swarm had decreased significantly. That same day the Aviation Color code was raised to Orange.
Geologic summary: The large central volcano of Bárdarbunga lies beneath the NW part of the Vatnajökull icecap, NW of Grímsvötn volcano, and contains a subglacial 700-m-deep caldera. Related fissure systems include the Veidivötn and Trollagigar fissures, which extend about 100 km SW to near Torfajökull volcano and 50 km NE to near Askja volcano, respectively. Voluminous fissure eruptions, including one at Thjorsarhraun, which produced the largest known Holocene lava flow on Earth with a volume of more than 21 cu km, have occurred throughout the Holocene into historical time from the Veidivötn fissure system. The last major eruption of Veidivötn, in 1477, also produced a large tephra deposit. The subglacial Loki-Fögrufjöll volcanic system located SW of Bárdarbunga volcano is also part of the Bárdarbunga volcanic system and contains two subglacial ridges extending from the largely subglacial Hamarinn central volcano; the Loki ridge trends to the NE and the Fögrufjöll ridge to the SW. Jökulhlaups (glacier-outburst floods) from eruptions at Bárdarbunga potentially affect drainages in all directions.
Mayon, Luzon (Philippines)
13.257°N, 123.685°E, Summit elev. 2462 m
During 13-19 PHIVOLCS reported growth of the new summit dome, slight ground deformation, and increased volcanic gas emission at Mayon. On 16-17 August a few rockfalls and one earthquake were detected. On 16-18 August moderate emission of white steam plumes drifted SE, SW, NNE and NE. PHIVOLCS had raised the Alert Level to 2 (on a scale of 0-5) on 15 August.
Geologic summary: Beautifully symmetrical Mayon volcano, which rises to 2462 m above the Albay Gulf, is the Philippines' most active volcano. The structurally simple volcano has steep upper slopes averaging 35-40 degrees that are capped by a small summit crater. Historical eruptions at this basaltic-andesitic volcano date back to 1616 and 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 devastated populated lowland areas. Mayon's most violent eruption, in 1814, killed more than 1200 people and devastated several towns.
Aira, Kyushu (Japan)
31.593°N, 130.657°E, Summit elev. 1117 m
During 11-15 August JMA reported 14 explosions from Showa Crater at Aira Caldera’s Sakurajima volcano that ejected ballistics 800-1300 m away. During 15-18 August were four more explosions with similar ballistic ejections. The explosions were accompanied by volcanic earthquakes and volcanic tremor. On most days faint to clear incandescence was visible using a high-sensitivity camera at night. On 13-17 August the Tokyo VAAC reported explosions with plumes that rose to an altitude of 1.5-3 km (5,000-10,000 ft) a.s.l. and drifted NE and N, though volcanic ash could not be identified in satellite data. 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.
Etna, Sicily (Italy)
37.734°N, 15.004°E, Summit elev. 3330 m
On 13 August INGV reported continued eruptive activity at New SE Crater of Etna, including Strombolian explosions accompanied by minor ash emissions. Lavacontinued to flow about 3 km NE towards Monte Simone. On 18 August INGV reported that the eruption at New SE Crater had ended on 15 August and lava flow activity had ceased as of 16 August.
Geologic summary: Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical volcanism, dating back to 1500 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km horseshoe-shaped caldera open to the east. Two styles of eruptive activity typically occur at Etna. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more of the three prominent summit craters, the Central Crater, NE Crater, and SE Crater (the latter formed in 1978). Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank.
14.473°N, 90.88°W, Summit elev. 3763 m
During 13-19 August, INSIVUMEH reported weak to moderate explosions at Fuego with incandescent blocks being expelled 500-800 m above the crater, activity accompanied on 14 and 16 August by white plumes that rose 200-300 m above the crater and drifted W. On 13 and 15 August INSIVUMEH reported rumbling from shock waves that rattled structures up to 8 km from the volcano in the villages of Panimaché I and II, Morelia, and others in this area, and on 17 August jet engine like sounds lasting 1-4 minutes. On most days incandescent blocks were expelled 50-400 m above the crater, and weak to moderate avalanches of blocks were channeled into the Las Lajas (SE), Trinidad (S), Ceniza (SSW), Taniluyá (SW), Santa Teresa and Barranca Honda canyons. Ash plumes rose 4.2-4.5 km (13,800-14,800 ft) a.s.l. and drifted 8-15 km W and SW. Ashfall was reported in Morelia (9 km SW), Panimaché (8 km SW), Panimaché II, Sangre de Cristo (8 km WSW), Yepocapa (8 km WNW), and Hagia Sophia. On 18 August the Washington VAAC reported several discrete ash emissions based on satellite and wind data.
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.
Kilauea, Hawaiian Islands (USA)
19.421°N, 155.287°W, Summit elev. 1222 m
During 13-19 August 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 15-18 August glow was visible during the night above outgassing pits on the northeast, south, and southeast edges of Pu`u `O`o's crater floor and at skylights along the June 27th flow lava tube. On 12 August these pits at the edges of the crater floor were identified in an overflight. The June 27th flow continued to advance into forest NE of Pu`u `O`o. The tube-fed flow slowed and widened over several days, and its distal tip was 9.4 km from the vent (straight-line distance) on 18 August. The flow also hosted a broad area of lava flow breakouts mid-way along its length that reached the forest about 5 km NE of the vent, on the N side of the current flow.
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.
Kuchinoerabujima, Ryukyu Islands (Japan)
30.443°N, 130.217°E, Summit elev. 657 m
JMA reported that during 13-19 August tremor and quakes were accompanied by no explosions at Kuchinoerabujima. On 13 August a white plume rose 600 m and on 18 August rose 50 m above the crater rim. The Alert Level remained at 3 (on a scale of 1-5).
Geologic summary: A group of young stratovolcanoes forms the eastern end of the irregularly shaped island of Kuchinoerabujima in the northern Ryukyus, 15 km west of Yakushima. Furutake, Shintake, and Noike were erupted from south to north, respectively, to form a composite cone that is parallel to the trend of the Ryukyu Islands. The highest peak, Furutake, reaches only 657 m above sea level. The youngest cone, 640-m-high Shintake, was 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.
Kusatsu-Shiranesan, Honshu (Japan)
36.618°N, 138.528°E, Summit elev. 2165 m
JMA reported that during 8-15 August volcanic earthquakes continued at Kusatsu-Shiranesan’s crater, although they had decreased from early August and tremor was absent. The Alert Level remains at 2 (on a scale of 1-5).
Geologic summary: The summit of Kusatsu-Shiranesan volcano, located immediately north of Asama volcano, consists of a series of overlapping pyroclastic cones and three crater lakes. The andesitic-to-dacitic volcano was formed in three eruptive stages beginning in the early to mid Pleistocene. The Pleistocene Oshi pyroclastic flow produced extensive welded tuffs and non-welded pumice that covers much of the east, south and SW flanks. The latest eruptive stage began about 14,000 years ago. All historical eruptions have consisted of phreatic explosions from the acidic crater lakes or their margins. Fumaroles and hot springs that dot the flanks have strongly acidified many rivers draining from the volcano. The crater was the site of active sulfur mining for many years during the 19th and 20th centuries.
14.381°N, 90.601°W, Summit elev. 2552 m
INSIVUMEH reported that during 13-19 August white and blueish white fumarolic plumes rose 50 m above Mackenney Crater at Pacaya and drifted 400-500 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 13-19 August steam-and-gas emissions with minor ash rose 300-1500 m above Popocatépetl’s crater and drifted NW, W, SW, and N. On most nights incandescence was observed, increasing in intensity with larger emissions. On 14-18 August heavy clouds were reported. The Alert Level remained at to 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 volcanic activity including explosions, long-period earthquakes, harmonic tremor, and tremor at Reventador on 13, 14, 18, and 19 August. On 13 August continuous steam with minor ash plumes rose 500 m above the summit and drifted NE. On 14 August clear views of the volcano showed no surface activity, and on 18-19 August the volcano was obscured by clouds.
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.
15.78°S, 71.85°W, Summit elev. 5967 m
On 13, 17, and 18 August the Buenos Aires VAAC reported volcanic ash at Sabancaya based on satellite, remote camera, and pilot reports.
Geologic summary: Sabancaya, located on the saddle between 6288-m-high Ampato and 6025-m-high 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 volcanoes, Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene age. Both Nevado Ampato and Nevado Sabancaya are only slightly affected by glacial erosion and consist of a series of lava domes aligned along a NW-SW trend. The name of 5967-m-high Sabancaya (meaning "tongue of fire" in the Quechua Indian 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.
San Miguel, El Salvador
13.434°N, 88.269°W, Summit elev. 2130 m
On 13-19 August SNET reported low seismic activity at San Miguel. On most days white and whitish gray gas plumes rose 100-300 m above the crater. On 14 August field work was completed that assessed damage to the town of San Jorge affected by debris flows caused by heavy rainfall on 10-11 August.
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
On 13-19 August INSIVUMEH reported that fumarolic columns rose to 2.7-2.8 km (8,800-9,200 ft) a.s.l. above Santiaguito, drifting to the S and SW. On most days the lava flow (2.5 km in length) moved towards and into Nima Canyon I. Collapse avalanches from the lava flow front generated columns of fine ash that rose 1.2-2 km (3,900-6,600 ft) a.s.l. , drifting over the Palajunoj area on 15 August. On 13-16 and 19 August INSIVUMEH reported white degassing plumes rising 200-400 above the crater and drifting SW, and noted decreased incandescence at the crater.
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 13-19 August eruptive activity continued at Shishaldin volcano. Infrasound sensors located at Dillingham and on Akutan Island detected sound waves from the direction of Shishaldin that are consistent with low-level activity at the volcano. On 13 August a pilot reported a low-level plume from Shishaldin. On the evening of 16 August web camera views showed a steam and gas plume. On 17-19 August elevated surface temperatures were detected in partly cloudy satellite views. Other days satellite and web camera views were obscured by weather. No significant activity was noted in seismic data. 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 8-14 August lava-dome extrusion onto Shiveluch’s SE flank was accompanied by moderate ash explosions, incandescence of the dome summit, hot avalanches, and fumarolic activity. On 11-14 August satellite data showed a thermal anomaly over the lava dome, and the volcano was obscured by clouds the other days of week. On 9 August the Tokyo VAAC reported an ash plume rose to 4.6 km (15,000 ft) a.s.l. The Aviation Color Coderemained 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.
Stromboli, Aeolian Islands (Italy)
38.789°N, 15.213°E, Summit elev. 924 m
On 13 August INGV reported that at Stromboli lava continued to flow along the E edge of the Sciara del Fuoco with a consistent effusion rate and reached the coast in the early morning.
Geologic summary: Spectacular incandescent nighttime explosions at Stromboli volcano have long attracted visitors to the "Lighthouse of the Mediterranean." Stromboli, the NE-most of the Aeolian Islands, has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout much of historical time. The small, 924-m-high island of Stromboli is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The Neostromboli eruptive period from about 13,000 to 5000 years ago was followed by formation of the modern Stromboli edifice. The active summit vents are located at the head of the Sciara del Fuoco, a prominent horseshoe-shaped scarp formed about 5000 years ago as a result of the most recent of a series of slope failures that extend to below sea level. The modern volcano has been constructed within this scarp, which funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild strombolian explosions, sometimes accompanied by lava flows, have been recorded at Stromboli for more than a millennium.
1.467°S, 78.442°W, Summit elev. 5023 m
During 13-19 August IG reported that moderate to high eruptive activity continued at Tungurahua, including volcanic tremor, blasts, and long-period and volcano-tectonic earthquakes. On most days cloudy conditions allowed only intermittent views of the volcano. On 14 August a “canon blast” sound shook structures in the town of Baños, followed by an ash plume that rose 1.5 km (4,900 ft) a.s.l. and drifted SW. On 13 August a lahar was reported in the Chontapamba sector that moved blocks 50 cm in size. On 15 August during the early morning an explosion and rockfall was heard and a light ashfall was reported in Choglontus. On 17 August glow was observed in the crater. On 18-19 August a fine black ashfall was reported in the areas of Pillate, Chontapamba, Bilbao, Mocha, Motilones, Quero, and Tisaleo. On 19 August a plume rose 2-3 km (6,600-9,800 ft) a.s.l. and drifted W and NW. During 13-19 August the Washington VAAC reported ongoing emissions, including volcanic ash and steam-and-gas plumes. On 14 August a short duration explosion and volcanic ash was reported.
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
During 13-17 August INGEMMET reported that seismicity has decreased and the eruption of Ubinas continued. Mild steam-and-gas emissions rose 200-400 m above the summit and drifted SE and NE.
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 8-14 August the moderate explosive eruption continued at Zhupanovsky. On 8 August staff of Volcanoes of Kamchatka Natural Park observed ash explosions twice an hour, with ash plumes rising up to 4 km (13,100 ft)a.s.l. drifting E. On 8 and 11-13 August satellite data showed that ash plumes rose to 4-4.5 km (13,100-14,800 ft)a.s.l. and drifted 80-100 km SE and NE Other days satellite data showed the volcano was obscured by clouds. On 12-13 August the Tokyo VAAC reported ash plumes to 3-4.9 km (10,000-16,000 ft) a.s.l that drifted SE, NE, and ESE.
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.