Active volcanoes in the world: July 9 - 15, 2014

Active volcanoes in the world: July 9 - 15, 2014

New activity/unrest was observed at 3 volcanoes from July 9 - 15, 2014. Ongoing activity was reported for 23 volcanoes.

New activity/unrest: Ambang, Sulawesi (Indonesia)  | Bulusan, Luzon (Philippines)  | Copahue, Central Chile-Argentina border

Ongoing activity: Aira, Kyushu (Japan)  | Bezymianny, Central Kamchatka (Russia)  | Dukono, Halmahera (Indonesia)  | Etna, Sicily (Italy)  | Fuego, Guatemala  | Karymsky, Eastern Kamchatka (Russia)  | Kilauea, Hawaiian Islands (USA)  | Merapi, Central Java (Indonesia)  | Nishinoshima, Japan  | Pacaya, Guatemala  | Popocatepetl, Mexico  | Reventador, Ecuador  | Sabancaya, Peru  | San Miguel, El Salvador  | Santa Maria, Guatemala  | Shishaldin, Fox Islands (USA)  | Shiveluch, Central Kamchatka (Russia)  | Sinabung, Indonesia  | Slamet, Central Java (Indonesia)  | 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.

New activity/unrest

Ambang, Sulawesi (Indonesia)
0.75°N, 124.42°E, Summit elev. 1795 m

On 3 July, CVGHM reported a significant increase in seismicity from Ambang, particularly shallow earthquakes (VB). During 1 June-2 July, 7-9 shallow volcanic (VB) and 2-9 deep volcanic (VA) earthquakes were detected per week, for totals of 33 VB and 29 VA earthquakes in that time. The Alert Level was raised to Level 2 on 3 July. An exclusion zone was placed around the crater with a radius of 1.5 km. Persistent diffuse gas emissions were observed reaching 10-25 m above the crater.

CVGHM noted that previous eruptions from Ambang were dominated by effusive lava flows and were punctuated by explosive eruptions producing pyroclastic flows and fallout. Ambang has an eruption frequency of once every 39-127 years; the last event recorded was a phreatic explosion in 2005. A persistent fumarolic field remains from that activity. CVGHM noted that a magmatic eruption generating pyroclastic flows would threaten communities SE of the summit including the villages of Bongkudai, Goaan, Purworejo, and Modayong.

Geologic summary: The compound Ambang volcano is the westernmost of the active volcanoes on the northern arm of Sulawesi. The 1795-m-high stratovolcano rises 750 m above lake Danau. Several craters up to 400 m in diameter and five solfatara fields are located at the summit. Ambang's only known historical eruption, of unspecified character, took place in the 1840s.

Bulusan, Luzon (Philippines)
12.77°N, 124.05°E, Summit elev. 1565 m

On 13 July, PHIVLOCS reported that several days of elevated seismicity at Bulusan continued. During the previous 24 hours, 13 volcanic earthquakes were recorded by the local network. GPS and leveling surveys determined that the volcano was slightly inflated. Alert Level 0 and the 4-km restricted zone, the Permanent Danger Zone (PDZ), were maintained due to the possibility of sudden and hazardous steam-driven or phreatic eruptions.

Geologic summary: Luzon's southernmost volcano, Bulusan, was constructed along the rim of the 11-km-diameter dacitic-to-rhyolitic Irosin caldera, which was formed about 36,000 years ago. Bulusan lies at the SE end of the Bicol volcanic arc occupying the peninsula of the same name that forms the elongated SE tip of Luzon. A broad, flat moat is located below the topographically prominent SW rim of Irosin caldera; the NE rim is buried by the andesitic Bulusan complex. Bulusan is flanked by several other large intracaldera lava domes and cones, including the prominent Mount Jormajan lava dome on the SW flank and Sharp Peak to the NE. The summit of 1565-m-high Bulusan volcano is unvegetated and contains a 300-m-wide, 50-m-deep crater. Three small craters are located on the SE flank. Many moderate explosive eruptions have been recorded at Bulusan since the mid-19th century.

Copahue, Central Chile-Argentina border
37.856°S, 71.183°W, Summit elev. 2953 m

SERNAGEOMIN reported that a phreatic explosion from Copahue occurred at 2023 on 4 July that deposited bombs (less than 12 cm in diameter), lapilli (less than 4 cm), ash, and gray clay smelling strongly of sulfuric acid along the E flank of the crater. During an overflight on 7 July, OVDAS officials observed the deposit and measured a moderate amount of gas emissions (an average of 4,000 tons per day of SO2), a relatively low level of water in the crater, and low temperatures of the fumaroles within El Agrio crater. DOAS stations had measured up to 18,000 tons/day of SO2 on the day of the explosion. An anomalous tremor signal was detected at 0823 on 5 July that was associated with an explosion from El Agrio crater; a microphone installation 13 km E also detected an acoustic signal. The explosion generated a plume 1,000 m above the crater. The Alert Level remained at Yellow.

Geologic summary: Volcán Copahue is an elongated composite cone constructed along the Chile-Argentina border within the 6.5 x 8.5 km wide Trapa-Trapa caldera that formed between 0.6 and 0.4 million years ago near the NW margin of the 20 x 15 km Pliocene Caviahue (Del Agrio) caldera. The eastern summit crater, part of a 2-km-long, ENE-WSW line of nine craters, contains a briny, acidic 300-m-wide crater lake (also referred to as El Agrio or Del Agrio) and displays intense fumarolic activity. Acidic hot springs occur below the eastern outlet of the crater lake, contributing to the acidity of the Río Agrio, and another geothermal zone is located within Caviahue caldera about 7 km NE of the summit. Infrequent mild-to-moderate explosive eruptions have been recorded at Copahue since the 18th century. Twentieth-century eruptions from the crater lake have ejected pyroclastic rocks and chilled liquid sulfur fragments.

Ongoing activity

Aira, Kyushu (Japan)
31.593°N, 130.657°E, Summit elev. 1117 m

During 11-14 July, JMA reported four large explosions that ejected deposits 800-1,300 m from Showa crater. Volcanic earthquakes decreased and tremor continued. The Tokyo VAAC reported that during 3-14 July plumes rose to altitudes of 2-3 km (7,000-10,000 ft) a.s.l. and drifted NE, SE, and E. 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 Bezymianny’s activity continued during 2-10 July; shallow earthquakes were registered. Satellite data showed the volcano frequently obscured by clouds. The Aviation Color Code remained at Orange.

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.

Dukono, Halmahera (Indonesia)
1.68°N, 127.88°E, Summit elev. 1335 m

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 12-15 July ash plumes from Dukono rose to an altitude of 2-3 km (7,000-10,000 ft) a.s.l. and drifted NE.

Geologic 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. Dukono is a complex volcano presenting a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of Dukono's summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.

Etna, Sicily (Italy)
37.734°N, 15.004°E, Summit elev. 3330 m

INGV reported that a new, small fissure (tens of meters long) developed on the E flank of Etna during 5-6 July. The vent was located around 3,015-3,025 m elevation. Weak spattering from this vent fed a lava flow that extended ~100 m within the saddle of the NE and SE craters and cones. Weak and sporadic strombolian explosions and small ash emissions were observed during 6-7 July from New SE Crater, but by 11 July this activity had ceased.

Activity from the new fissure continued through 11 July with frequent strombolian explosions that were audible in nearby towns. The lava flow diverged, and the longest of the two branches extended ~1.5 km, reaching the bottom of Valle del Leone.

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.

Fuego, Guatemala
14.473°N, 90.88°W, Summit elev. 3763 m

During 30 June-14 July, INSIVUMEH frequently reported a white fumarolic plume rising from Fuego’s summit extending up to 4,000 m (13,123 ft) a.s.l.. Weak-to-moderate explosions generated ash plumes to similar heights during 30 June and 1, 4, 6, 7, and 9-13 July. Rumbling and jetting sounds often accompanied these explosions, often with durations of 1-5 minutes. Pulses of incandescence reached 50-100 m above the rim on 30 June, and 6, 7, and 12 July. Remobilized ash reduced visibility on 4, 9, and 10 July. Surges of lava and incandescent avalanches traveled from the summit down the flanks on 1 July (~150 m into the Trinidad drainage), 6 July (100 m into Taniluya and 200 m into the Ceniza), 11 July (~100 m into Taniluya), 12 July (Santa Teresa, Taniluya, Ceniza, Trinidad, Las Lajas, and Honda), and 13 July (~400 m into the Ceniza).

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 that Strombolian activity continued at Karymsky during 3-10 July. Satellite views were obscured by clouds or the imagery showed no activity. The Aviation Color Code remained at Orange.

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 2-14 July HVO reported that the circulating lava lake occasionally rose and fell in the deep pit within Kilauea's Halema`uma`u Crater. The lava-lake level fluctuated between 30 and 45 m below the Overlook crater rim; on 13 July, the level dropped 45-50 m during periods of spattering. Weak inflation was measured at the summit during 2-8 July, deflation during 9-10 July, no significant deformation during 11-13 July, and slight inflation on 14 July. Gas emissions remained elevated; during the weeks ending on 1 and 8 July, the summit SO2 emission rates were 3,800-8,400 tonnes/day and 5,800-6,900 tonnes/day, respectively. Earthquakes during 2-7 July (11-21/day) and 8-14 July (5-27/day) were strong enough to be located beneath Kilauea. 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 3 July, the total SO2 emission rate from all East Rift Zone sources was 500 tonnes per day. During 2-14 July, four lava ponds within cones occupied the crater floor of Pu`u`O`o. The vent which opened on the NE flank of Pu`u`O`o on 27 June remained active and supplied a flow extending NE, constructing a lava shield that continued to expand until 10 July. This new flow cut off lava supply to the Kahauale`a 2 flow, which by 3 July was no longer active. The new shield developed a perched lava pond which crusted over and became quiescent when the pond spilled over on 11 July. Lava continued to erupt from the base of the structure, supplying flows that accumulated around the flat-lying terrain at the base of Pu`u`O`o until 14 July. Continuous deflation was measured at Pu`u`O`o.

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.

Merapi, Central Java (Indonesia)
7.542°S, 110.442°E, Summit elev. 2968 m

PVMBG reported that during 4-10 July seismicity at Merapi fluctuated at normal levels. Deformation measurements showed general inflation. Solfatara plumes rose 450 m above the summit on 4 July. The Alert Level remained at 1 (on a scale of 1-4).

Geologic 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. Merapi is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi volcano beginning 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 volcano's western-to-southern flanks and caused many fatalities during historical time. The volcano is the object of extensive monitoring efforts by the Merapi Volcano Observatory.

Nishinoshima, Japan
27.247°N, 140.874°E, Summit elev. 25 m

Tokyo VAAC reported volcanic ash from Nishinoshima at 3 km (10,000 ft) a.s.l. at 2203 on 30 June; the plume extended NE. However, ash was not visible in satellite images. The University of Hawaii reported that Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data detected thermal anomalies and issued MODVOLC alerts during 25 June-13 July with the exceptions of 8, 11, and 12 July.

Geologic summary: The small island of Nishinoshima was recently enlarged when it was joined to several new islands that formed during an eruption in 1973-74. Water discoloration has been observed on several occasions since. The 700-m-wide island is the summit of a massive submarine volcano that has prominent satellitic peaks to the S, W, and NE. The summit of the southern cone rises to within 214 m of the sea surface 9 km SSE.

Pacaya, Guatemala
14.381°N, 90.601°W, Summit elev. 2552 m

INSIVUMEH reported that on most days during 30 June-13 July, fumarolic plumes rose above Pacaya and drifted up to 1 km W, SW, and S. Associated seismicity was notable on 4, 6, 9-11, and 13 July. Elevated seismicity on 10 July corresponded to minor explosions from Mackenney Crater.

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.

Popocatepetl, Mexico
19.023°N, 98.622°W, Summit elev. 5426 m

CENAPRED reported that during 24 June-15 July, seismicity at Popocatépetl indicated continuing emissions of water vapor, gas, and occasional small amounts of ash. Cloud cover sometimes prevented visual observations. Slight nighttime incandescence was observed during 25 and 26 June and also during 1-3, 6-8, and 10-15 July. Explosions from the summit were detected an average of 10 times each day, producing plumes with minor ash content that rose 500-2,500 m above the crater and drifted NE and NW. Activity increased in early July; up to 216 explosions (low and moderate intensity) were detected over 24 hours on 9 July. CENAPRED reported harmonic tremor on 2 July (maximum of 80 minutes in 24 hours) and 12 July (minimum of 8 minutes). 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.

Reventador, Ecuador
0.077°S, 77.656°W, Summit elev. 3562 m

IG reported that although cloud cover often prevented observations of Reventador, during 30 June and 2, 4, and 9-12 July ash emissions were seen. In the afternoon of 30 June, a diffuse ash plume was visible rising from the summit. Activity increased on 2 July when 41 explosions were recorded, as well as 27 long-period earthquakes and 15 episodes of tremor associated with emissions. A 2-km-high gas-and-ash plume was observed rising from the summit on the morning of 2 July that drifted SE and later that night an explosion was heard. The IG reported that SOTE (Sistema de Oleoducto Transecuatoriano) personnel heard explosions during the morning of 8 July. The next morning, SOTE personnel noted that the summit was clear and a gas-and-ash plume was rising from the summit up to 2 km above the crater rim. Diffuse ash plumes were also noted on 10 and 11 July that reached 1.5 km above the crater and drifted NW.

The seismic network detected the highest number of explosion signatures during 2-5 July when 34-45 events per day were detected. Up to 12 episodes of harmonic tremor per day occurred during 4 and 5 July. The highest number of long-period earthquakes occurred during 10-11 July: 90 events per day. Tremor signatures associated with emissions had a wide range during this reporting period (0-28 per day), but typically numbered less than 15 per day.

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.

Sabancaya, Peru
15.78°S, 71.85°W, Summit elev. 5967 m

IGP reported that during 12-27 June there were renewed signs of activity from Sabancaya. Fumarolic activity increased and gases were notably more blue and gray. Seismicity also increased, particularly long-period (LP) earthquakes (~100 LP events per day during 18, 19, and 21 June). Since 6 June, hybrid earthquakes were detected; IGP noted that this seismicity can be attributed to rising magma. During 6-10 July, a daily average of 11 hybrid earthquakes was recorded. In the past few weeks, volcano-tectonic (VT) earthquakes migrated closer to the volcano, especially when the locations were compared with those from 2013. Within a week, the concentration of VT earthquakes had moved ~10 km closer to the crater, reaching a distance ~6 km N of the crater. This activity prompted IGP to install a new seismometer to augment their monitoring capabilities, now comprising six seismometers.

From mid-June through 10 July, fumarolic activity continued and white plumes were visible, although with less intensity within the last two weeks. Seismicity increased during this time period, particularly on 30 June and 1 July when a daily average of 87 LP earthquakes was recorded. From 27 June through 6 July, there was a daily average of 44 VT earthquakes. VT earthquakes were also occurring close to the crater. There were three persistent clusters of VT earthquakes near the crater: 6 km N, 16 km NE, and 10 km E.

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

According to the Ministry of Environment and Natural Resources (MARN), elevated activity was detected on 10 July from San Miguel. RSAM had increased significantly and was also high on 14 July, but decreased the next day. On 15 July MARN reported that seismicity was continuing from the N flank. SO2 flux measurements indicated a significant decrease of gas.

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 30 June-14 July the active lava dome of Santiaguito was visibly degassing and generating plumes rising up to ~3,000 m (10,000 ft) a.s.l. that tended to drift SW. Weak explosions with some rumbling sounds occurred during this time period and ashfall was reported in the high terrain of Parcelamiento Monte Claro (S) on 2 and 14 July. Explosions were observed on 5, 7, and 10 July that ejected incandescent tephra up to 50 m above the crater rim. The active lava flow front on the E flank was also a frequent source of incandescence that generated hot avalanches into the drainages of Nimá 1 (E) and San Isidro (SW). On 2 and 10 July slope failures were reported from the scarp remaining from the 9 May 2014 eruption.

On 15 July at 1430 lahars were triggered by heavy rainfall. INSIVUMEH reported that lahars were channelized within Nimá 1, San Isidro, and the tributaries of Samala. Seismic stations detected the flow; hot volcanic material dominated the lahars as well as tree trunks and branches and blocks 1-2 m in diameter. Vapor was rising from the lahars and there was a strong sulfur odor. INSIVUMEH extended the warning for the region, including the high bridge of Castillo Armas (on the international highway NE of San Sebastián) due to the convergence of several flows upstream from that site.

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 2-15 July low-level seismicity continued at Shishaldin volcano. Elevated surface temperatures at the summit were detected. A steam and gas plume was intermittently visible rising from the summit and drifting downwind, although satellite and web-camera images were mostly obscured due to clouds. On 9 July small explosions, probably within the summit cone, were detected on seismic and infrasound networks. 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 a`a 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 3-10 July lava-dome extrusion onto Shiveluch’s SE flank was accompanied by ash explosions, incandescence, hot avalanches, and fumarolic activity. Ash plumes rose to 7 km (23,000 ft) a.s.l. on 30 June and 11 km (36,000 ft) a.s.l. during 5-8 July. During 7-8 July, satellite images detected ash plumes extending 280 km SE of the volcano. 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.

Sinabung, Indonesia
3.17°N, 98.392°E, Summit elev. 2460 m

CVGHM reported a white plume that was occasionally brown and blue reaching 100-2,000 m above Sinabung’s crater during 8-14 July. Pyroclastic flows were observed on 10 and 12 July from the W side of the crater. On 10 July, the hot flows reached a maximum of 3 km S while the flows on 12 July extended 3-4 km S. A spokesman from the national disaster management agency noted that hot ashfall occurred in several places around the Karo district, but did not merit further evacuations. CVGHM reported that SO2 emissions were measured once during 8-14 July and yielded 1,252 tonnes/day; during the elevated activity of 11-18 January 2014 values were as high as 3,796 tonnes/day. The Alert Level remained at 3 (on a scale of 1-4).

Geologic summary: Gunung Sinabung is a Pleistocene-to-Holocene stratovolcano with many lava flows on its flanks. The migration of summit vents along a N-S line gives the summit crater complex an elongated form. The youngest crater of this conical, 2460-m-high andesitic-to-dacitic volcano is at the southern end of the four overlapping summit craters. An unconfirmed eruption was noted in 1881, and solfataric activity was seen at the summit and upper flanks of Sinabung in 1912. No confirmed historical eruptions were recorded prior to explosive eruptions during August-September 2010 that produced ash plumes to 5 km above the summit.

Slamet, Central Java (Indonesia)
7.242°S, 109.208°E, Summit elev. 3428 m

CVGHM reported that incandescence had been visible 14 times in May and there were ash eruptions reaching 150-1,500 m above Slamet’s summit that drifted NW and W. White plumes were typically visible 50-800 m above the summit in May and June. There were 14 moderate ash eruptions during 15-30 June that generated plumes 500-1,400 m above the summit and drifted N and W. Incandescence was visible three times in June. During 1-2 July, there were 17 moderate ash plumes that generated plumes 300-1,200 m above the summit that drifted N and W. Alert Level 2 was maintained and visitors and tourists were prohibited from approaching the crater within a radius of 2 km.

Geologic summary: Slamet, Java's second highest volcano at 3428 m and one of its most active, has a cluster of about three dozen cinder cones on its lower SE-NE flanks and a single cinder cone on the western flank. It is composed of two overlapping edifices, an older basaltic-andesite to andesitic volcano on the west and a younger basaltic to basaltic-andesite one on the east. Gunung Malang II cinder cone on the upper E flank on the younger edifice fed a lava flow that extends 6 km E. Four craters occur at the summit of Gunung Slamet, with activity migrating to the SW over time. Historical eruptions, recorded since the 18th century, have originated from a 150-m-deep, 450-m-wide, steep-walled crater at the western part of the summit and have consisted of explosive eruptions generally lasting a few days to a few weeks.

Stromboli, Aeolian Islands (Italy)
38.789°N, 15.213°E, Summit elev. 924 m

INGV reported that during 30 June-1 July, small landslides occurred on Stromboli's Sciara del Fuoco. A new lava flow that began on 7 July flowed from the high part of Sciara del Fuoco (N2) and followed the path of the previous flows. A hot avalanche occurred at 0733 that reached the coastline and was followed by a lava flow. Two other lava flows began from the same location (N2); one during the afternoon of 9 July that was accompanied by small landslides and another on 10 July.

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.

Tungurahua, Ecuador
1.467°S, 78.442°W, Summit elev. 5023 m

IG reported that Tungurahua had low levels of seismicity and poor viewing conditions during 24-27 June and in July during 1-9 and 14. Heavy rain during the night of 24 June and morning of 25 June generated small lahars that caused damage to the Baños- Penipe highway. During the afternoon of 28 June clear viewing conditions allowed observations of a 100-m-high white plume rising from the summit crater. Otherwise, clear conditions revealed quiescence at the summit. Heavy rain during the night of 7 July and the following morning generated lahars in the drainages of Mandur to the NW: Pondoa, Cusúa, and Pingullo. A major road was destroyed in the area of Asupashal and the flow through Juive (NW) carried blocks up to 50 cm. A small lahar on 14 July was detected in the Juive drainage after heavy rainfall during the prior evening.

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.

Ubinas, Peru
16.355°S, 70.903°W, Summit elev. 5672 m

IGP reported that the eruption of Ubinas was continuing during 12 June-10 July. During 12-30 June six explosions generated plumes 1,400-3,600 m above the crater. Volcanic tremor was associated with ash emissions during 12-21, 25, and 26 June. During 28-29 June more than 1,000 hybrid earthquakes were recorded, but volcano-tectonic earthquakes were scarce. A moderate explosion on 30 June generated an incandescent plume. After more than 50 hours of tremor, a moderate explosion occurred at 0858 on 30 June; the plume reached 1,800 m above the crater and ejected tephra 1,500 m down the NW flank.

During 30 June-10 July IGP detected five, small-sized explosions that generated plumes 400-1,500 m above the crater. Seismicity was also reduced during this period; the greatest number of hybrid earthquakes was registered on 6 July when a swarm of 115 earthquakes occurred.

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 2, 5, and 9 July, moderate gas-and-steam activity was observed at Zhupanovsky. An ash plume up to 6 km (19,700 ft) a.s.l. was observed on 9 July. Satellite data showed an ash plume extending up to 450 km E and SE of the volcano during 9-10 July. The Aviation Color Code was maintained at Orange.

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.

Source: GVP

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