New unrest has been noticed around 7 volcanoes, ongoing activity was reported for 7 volcanoes. This report covers active volcanoes in the world recorded from September 12 – September 18 2012 based on Smithsonian/USGS criteria.
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. This is not a comprehensive list of all of Earth’s volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the “Criteria and Disclaimers” section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.
New Activity/Unrest: | Fuego, Guatemala | Gamalama, Halmahera | Grozny Group, Iturup Island | Little Sitkin, Aleutian Islands | Lokon-Empung, Sulawesi | San Cristóbal, Nicaragua | Soputan, Sulawesi
Ongoing Activity: | Batu Tara, Komba Island (Indonesia) | Karymsky, Eastern Kamchatka (Russia) |Kilauea, Hawaii (USA) | Popocatépetl, México | Sakura-jima, Kyushu | Shiveluch, Central Kamchatka (Russia) | Telica, Nicaragua
14.473°N, 90.880°W; summit elev. 3763 m
In a special bulletin on 13 September, INSIVUMEH reported that activity at Fuego increased, starting the sixth eruption in 2012. Lava flows traveled 600 m down the Taniluyá drainage (SSW) and the Las Lajas drainage (SE), producing block avalanches that reached vegetated areas. Strombolian explosions generated ash plumes that rose 3 km above the crater and drifted SW and 12 km W. Ash fell in multiple areas, including the villages of Panimaché (8 km SW), Morelia (8 km SW), Santa Sofia (12 km SE), Sangre de Cristo (8 km WSW), Palo Verde, San Pedro Yepocapa (8 km NW), Santiago Atitlan (42 km NW), San Lucas Toliman (32 km NW), Mazatenango (68 km W), Suchitepéquez, Retalhuleu (86 km W), and Santa Lucia Cotzumalguapa (23 km SW). Explosions produced degassing sounds and rumbling noises, accompanied by shock waves that vibrated structures on the SW flank. Pyroclastic flows traveled down the Las Lajas and Ceniza (SSW) drainages, producing ash plumes. CONRED increased the Alert Level to Orange (third highest on a four-color scale). About 10,600 people evacuated from nearby communities including Yepocapa, San Juan Alotenango (9 km ENE), Sacatepéquez. Evacuation shelters were set up in Santa Lucia Cotzumalguapa.
Later that day seismicity decreased, ash plumes rose 300 m above the crater and drifted W and NW, fewer pyroclastic flows were observed, and the rate of explosions slowed. Ashfall was reported in Panimaché, Morelia, and Sangre de Cristo. Lava flows in the Ceniza drainage were 1 km long and 150 m wide, and in Las Lajas were 700 m long and 100 m wide. CONRED noted that residents began to return to their homes on 14 September.
During 14-18 September explosions generated rumbling noises; ash plumes that rose 400-900 m above the crater drifted 7-8 km W and SW, causing ashfall in Sangre de Cristo, Panimaché I, and Panimaché II. Lava flows were at most 1.2 km long in the Taniluyá drainage and 200 m long in the Ceniza drainage during 14-16 September; flows were not observed during 17-18 September.
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 3,763-m-high Fuego and its twin volcano to the N, Acatenango. Construction of Meseta volcano continued until the late Pleistocene or early Holocene, after which growth of the modern Fuego volcano continued the southward migration of volcanism that began at Acatenango. Frequent vigorous historical eruptions have been recorded at Fuego since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows. The last major explosive eruption from Fuego took place in 1974, producing spectacular pyroclastic flows visible from Antigua.
0.80°N, 127.33°E; summit elev. 1715 m
CVGHM reported that during 1-14 September cloudy weather and fog at Gamalama mostly prevented observations from the post in Marikurubu and from S Ternate (S, SE, and E part of island); white plumes were sometimes observed rising 10 m above the crater. A phreatic eruption on 15 September at 2027 produced ashfall in Ternate. An eruption at 1415 the next day was accompanied by rumbling sounds. A plume rose 1 km and drifted SE and S, producing ashfall at the Gamalama observation post five minutes later. Neither eruption was observed due to fog. The Alert Level was raised to 3 (on a scale of 1-4) on 16 September. Visitors and residents were warned not to approach the crater within a radius of 2.5 km.
Geologic summary: Gamalama (Peak of Ternate) is a near-conical stratovolcano that comprises the entire island of Ternate off the western coast of Halmahera and is one of Indonesia’s most active volcanoes. The island of Ternate was a major regional center in the Portuguese and Dutch spice trade for several centuries, which contributed to the thorough documentation of Gamalama’s historical activity. Three cones, progressively younger to the N, form the summit of Gamalama, which reaches 1,715 m. Several maars and vents define a rift zone, parallel to the Halmahera island arc, that cuts the volcano. Eruptions, recorded frequently since the 16th century, typically originated from the summit craters, although flank eruptions have occurred in 1763, 1770, 1775, and 1962-63.
GROZNY GROUP, Iturup Island
45.026°N, 147.922°E; summit elev. 1211 m
Based on visual observations and analyses of satellite imagery, SVERT reported that during 10-17 September fumarolic activity at Grozny Group was at a medium intensity. The Aviation Color Code was lowered to Green.
Geologic summary: The Grozny volcano group in central Iturup Island contains the complex volcanoes of Ivan Grozny and Tebenkov. The former has a 3-3.5 km diameter caldera that is open to the south, where the large, 1158-m-high andesitic Grozny extrusion dome (also known as Etorofu-Yake-yama) was emplaced. Several other lava domes of Holocene age were constructed to the NE; extrusion of these domes has constricted a former lake in the northern side of the caldera to an extremely sinuous shoreline. The forested andesitic Tebenkov volcano, also known as Odamoi-san, lies immediately to the NE of the Grozny dome complex. The large Machekh crater, which displays strong fumarolic activity, lies immediately south of Tebenkov. Historical eruptions, the first of which took place in 1968, have been restricted to Ivan Grozny.
LITTLE SITKIN, Aleutian Islands
51.95°N, 178.543°E; summit elev. 1174 m
AVO reported that during 11-18 September seismic activity at Little Sitkin remained elevated and satellite views were obscured by clouds. Two earthquake swarms were detected on 11 and 13 September. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.
Geologic summary: Diamond-shaped Little Sitkin Island is bounded by steep cliffs on the east, north, and NE sides. Little Sitkin volcano contains two nested calderas. The older, nearly circular Pleistocene caldera is 4.8 km wide, may have once contained a caldera lake, and was partially filled by a younger cone formed mostly of andesitic and dacitic lava flows. The elliptical younger caldera is 2.7 x 4 km wide; it lies within the eastern part of the older caldera and shares its eastern and southern rim. The younger caldera partially destroyed the lava cone within the first caldera and is of possible early Holocene age. Young-looking dacitic lava flows, erupted in 1828 (Kay, in Wood and Kienle 1990), issued from the central cone within the younger caldera and from a vent on the west flank outside the older caldera. Fumarolic areas are found near the western coast, along the NW margin of the older caldera, and from the summit crater down the southern flank for a 1 km distance.
1.358°N, 124.792°E; summit elev. 1580 m
According to the Darwin VAAC, ground-based observers reported that on 15 September an ash plume from Lokon-Empung rose to an altitude of 3 km (10,000 ft) a.s.l. On 15 September satellite imagery showed an ash plume drifting 185 km SE.
Geologic summary: The twin volcanoes Lokon and Empung, rising about 800 m above the plain of Tondano, are among the most active volcanoes of Sulawesi. Lokon, the higher of the two peaks (whose summits are only 2.2 km apart) has a flat, craterless top. The morphologically younger Empung volcano has a 400-m-wide, 150-m-deep crater that erupted last in the 18th century, but all subsequent eruptions have originated from Tompaluan, a 150 x 250 m wide double crater situated in the saddle between the two peaks. Historical eruptions have primarily produced small-to-moderate ash plumes that have occasionally damaged croplands and houses, but lava-dome growth and pyroclastic flows have also occurred.
SAN CRISTOBAL, Nicaragua
12.702°N, 87.004°W; summit elev. 1745 m
On 10 September, INETER reported that seismicity decreased after the 8 September eruption at San Cristóbal. Sulfur dioxide emissions had decreased since the previous day. During 10-11 September steam plumes rose 200-300 m above the crater and drifted W. Three small explosions on 11 September generated ash-and-gas plumes that rose 300 m above the crater and drifted W. An explosion and ash venting was observed a few hours later; a plume drifted S and ash fell on the flanks. The seismic network detected small explosions on 13 September. Sulfur dioxide gas emissions were above normal, and similar to levels detected on 8 September. Sulfur dioxide gas emissions increased on 14 September. The next day a small explosion was observed and gas plumes drifted NE. Gas plumes drifted N on 17 September.
Geologic summary: The San Cristóbal volcanic complex, consisting of five principal volcanic edifices, forms the NW end of the Marrabios Range. The symmetrical 1,745-m-high youngest cone, San Cristóbal itself (also known as El Viejo), is Nicaragua’s highest volcano and is capped by a 500 x 600 m wide crater. El Chonco, with several flank lava domes, is located 4 km to the west of San Cristóbal; it and the eroded Moyotepe volcano, 4 km to the NE of San Cristóbal, are of Pleistocene age. Volcán Casita contains an elongated summit crater and lies immediately E of San Cristóbal; Casita was the site of a catastrophic landslide and lahar in 1998. The Plio-Pleistocene La Pelona caldera is located at the eastern end of the San Cristóbal complex. Historical eruptions from San Cristóbal, consisting of small-to-moderate explosive activity, have been reported since the 16th century. Some other 16th-century eruptions attributed to Casita volcano are uncertain and may pertain to other Marrabios Range volcanoes.
1.108°N, 124.73°E; summit elev. 1784 m
Based on information from US Air Force Weather Agency (AFWA), the Darwin VAAC reported that an ash plume from Soputan rose to an altitude of 9.1 km (30,000 ft) a.s.l. on 18 September. The VAAC also noted that a sulfur dioxide alert was issued by the Support to Aviation Control Service (SACS).
Geologic summary: The small conical volcano of Soputan on the southern rim of the Quaternary Tondanocaldera is one of Sulawesi’s most active volcanoes. During historical time the locus of eruptions has included both the summit crater and Aeseput, a prominent NE-flank vent that formed in 1906 and was the source of intermittent major lava flows until 1924.
BATU TARA, Komba Island (Indonesia)
7.792°S, 123.579°E; summit elev. 748 m
Based on analyses of satellite imagery, the Darwin Volcanic Ash Advisory Centre (VAAC) reported that during 12-16 September ash plumes from Batu Tara rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 28-130 km W and NW.
Geologic summary: The small isolated island of Batu Tara in the Flores Sea about 50 km north of Lembata (formerly Lomblen) Island contains a scarp on the eastern side similar to the Sciara del Fuoco of Italy’s Stromboli volcano. Vegetation covers the flanks of Batu Tara to within 50 m of the 748-m-high summit. Batu Tara lies north of the main volcanic arc and is noted for its potassic leucite-bearing basanitic and tephritic rocks. The firsthistorical eruption from Batu Tara, during 1847-52, produced explosions and a lava flow.
KARYMSKY, Eastern Kamchatka (Russia)
54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported weak-to-moderate seismic activity from Karymsky during 7-14 September. Seismic data indicated that ash plumes possibly rose to an altitude of 3 km (9,800 ft) a.s.l. Satellite imagery showed a thermal anomaly on the volcano on 7, 10, and 12 September. 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 about 7,600-7,700 radiocarbon years ago. Construction of the Karymsky stratovolcano began about 2,000 years later. The latest eruptive period began about 500 years ago, following a 2,300-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. Most seismicity preceding Karymsky eruptions has originated beneath Akademia Nauk caldera, which is located immediately S of Karymsky volcano and erupted simultaneously with Karymsky in 1996.
KILAUEA, Hawaii (USA)
19.421°N, 155.287°W; summit elev. 1222 m
During 12-18 September HVO reported that the circulating lava lake periodically rose and fell in the deep pit within Kilauea’s Halema’uma’u Crater. The gas plume from the vent continued to deposit variable amounts ofspatter and Pele’s hair, and possible crater wall veneer, onto nearby areas. Lava flows were active above the abandoned Royal Gardens subdivision. At Pu’u ‘O’o Crater, incandescence from the S and E pits on the crater floor, and from the W edge of the crusted N pit, was often visible. An opening in the roof of the lava tube at the base of the SE flank of Pu’u ‘O’o also continued to glow. On 14 September HVO geologists estimated that thelava lake in the E pit was about 10 m below the rim.
Geologic summary: Kilauea, one of five coalescing volcanoes that comprise the island of Hawaii, is one of the world’s most active volcanoes. Eruptions at Kilauea originate primarily from the summit caldera or along one of the lengthy E and SW rift zones that extend from the caldera to the sea. About 90% of the surface of Kilauea is formed of lava flows less than about 1,100 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.
19.023°N, 98.622°W; summit elev. 5426 m
CENAPRED reported that during 12-18 September seismicity at Popocatépetl indicated continuing gas-and-steam emissions that sometimes contained ash; cloud cover often prevented visual observations of the volcano. Incandescence from the crater was observed most nights. On 13 September gas-and-steam plumes rose 2 km above the crater and drifted NE. Later that day a gas-and-ash plume rose 2 km. Incandescent tephra was ejected 500 m and fell on the NE flanks. On 14 September incandescent tephra fell on the N flank and gas-and-ash plumes rose 1 km. The next day gas-and-ash plumes again rose 1 km. During 16-18 September gas plumes continued to rise 1 km at most and drifted NE, NW, and SW. The Alert Level remained at Yellow, Phase Two.
Geologic summary: Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5,426 m 70 km SE of Mexico City and is North America’s second-highest volcano. Frequent historical eruptions have been recorded since the beginning of the Spanish colonial era. A small eruption on 21 December 1994 ended five decades of quiescence. Since 1996 small lava domes have incrementally been constructed within the summit crater and destroyed by explosive eruptions. Intermittent small-to-moderate gas-and-ash eruptions have continued, occasionally producing ashfall in neighboring towns and villages.
31.585°N, 130.657°E; summit elev. 1117 m
Based on information from JMA, the Tokyo VAAC reported that explosions from Sakura-jima during 13-15 and 17-18 September often produced plumes that rose to altitudes of 2.1-3.7 km (7,000-12,000 ft) a.s.l. The plumes sometimes drifted NW, N, and NE. On 14 September a pilot observed an ash plume that rose to an altitude of 3.4 km (11,000 ft) a.s.l.
Geologic summary: Sakura-jima, one of Japan’s most active volcanoes, is a post-caldera cone of the Aira caldera at the northern half of Kagoshima Bay. Eruption of the voluminous Ito pyroclastic flow was associated with the formation of the 17 x 23-km-wide Aira caldera about 22,000 years ago. The construction of Sakura-jima began about 13,000 years ago and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kita-dake summit cone ended about 4,850 years ago, after which eruptions took place at Minami-dake. 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.
SHIVELUCH, Central Kamchatka (Russia)
56.653°N, 161.360°E; summit elev. 3283 m
Based on visual observations and analyses of satellite data, KVERT reported that during 7-14 September a viscous lava flow continued to effuse on the NW flank of Shiveluch’s lava dome, and was accompanied by hot avalanches and fumarolic activity. Satellite imagery showed a thermal anomaly over the lava dome on 9, 11, and 13 September; cloud cover prevented observations on the other days, and during 15-16 September. Seismicity increased on 18 September. At 1119 observers noted that an ash plume rose to an altitude of 8 km (26,200 ft)a.s.l. and drifted 137 km SE. 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 and forms one of Kamchatka’s largest and most active volcanoes. The currently active Molodoy Shiveluch lava-dome complex was constructed during the Holocene within a large breached caldera formed by collapse of the massive late-Pleistocene Strary Shiveluch volcano. At least 60 large eruptions of Shiveluch have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Frequent collapses of lava-dome complexes, most recently in 1964, have produced large debris avalanches whose deposits cover much of the floor of the breached caldera. Intermittent explosive eruptions began in the 1990s from a new lava dome that began growing in 1980. The largest historicaleruptions from Shiveluch occurred in 1854 and 1964.
12.602°N, 86.845°W; summit elev. 1061 m
During 10-11 September INETER reported “jet” sounds from Telica, two incandescent fumaroles, and gas-and-steam plumes rising 100-200 m above the crater. On 11 September two small explosions occurred in the crater. During 12-14 and 17 September gas plumes rose 30-150 m and incandescence from the crater was observed. Gas measurements on 14 and 17 September showed normal levels of sulfur dioxide emissions.
Geologic summary: Telica, one of Nicaragua’s most active volcanoes, has erupted frequently since the beginning of the Spanish era. The Telica volcano group consists of several interlocking cones and vents with a general NW alignment. Sixteenth-century eruptions were reported at symmetrical Santa Clara volcano at the SW end of the Telica group. However, its eroded and breached crater has been covered by forests throughout historical time, and these eruptions may have originated from Telica, whose upper slopes in contrast are unvegetated. The steep-sided cone of 1061-m-high Telica is truncated by a 700-m-wide double crater; the southern crater, the source of recent eruptions, is 120 m deep. El Liston, immediately SE of Telica, has several nested craters. The fumaroles and boiling mudpots of Hervideros de San Jacinto, SE of Telica, form a prominent geothermal area frequented by tourists, and geothermal exploration has occurred nearby.
Source: Global Volcanism Program
Featured image: Satellite image taken in December 2010 of the San Cristóbal volcano. This active volcano rises above the town of Chichigalpa, locted in Chinandega, Nicaragua. In the image, you can see the gas and ash clouds emanating from the volcano’s caldera. These clouds and prevailing winds have served to remove all vegetation from the volcano’s southwestern flank.
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