Each week, The Meteo Times provides information on new and continuing volcanic activity throughout the world. The TMT World Volcanic Activity Report is filed in conjunction with the most up-to-date date from the Smithsonian Institute. This week's report features updates from Monsterrat, Guatemala, New Zealand, Indonesia, USA, Mexico, Russia, Japan, Ecuador and Colombia.
The TMT interactive volcano/earthquake world map may be viewed here.
MONOWAI SEAMOUNT Kermadec Islands (SW Pacific)
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| NASA image of Havre Seamount eruption and initial formation of pumice raft. |
According to Institute of Geological & Nuclear Sciences Limited (GNS) in a media release on 11 August, the Laboratoire de Géophysique (Papeete, Tahiti) reported that seismographs in Rarotonga recorded eruptive activity at Monowai seamount on 3 August. The activity then stopped overnight.
Geologic Summary. Monowai seamount, also known as Orion seamount, rises to within 100 m of the sea surface about halfway between the Kermadec and Tonga island groups. The volcano lies at the southern end of the Tonga Ridge and is slightly offset from the Kermadec volcanoes. Small parasitic cones occur on the north and west flanks of the basaltic submarine volcano, which rises from a depth of about 1500 m and was named for one of the New Zealand Navy bathymetric survey ships that documented its morphology. A large 8.5 x 11 km wide submarine caldera with a depth of more than 1500 m lies to the NNE. Numerous eruptions from Monowai have been detected from submarine acoustic signals since it was first recognized as a volcano in 1977. A shoal that had been reported in 1944 may have been a pumice raft or water disturbance due to degassing. Surface observations have included water discoloration, vigorous gas bubbling, and areas of upwelling water, sometimes accompanied by rumbling noises.
Monowai Seamount Information from the Global Volcanism Program
SOUFRIERE HILLS Montserrat
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| Image c/o www.mvo.ms |
On 9 August the inside of the collapse scar was partially visible during a helicopter flight. Fumarolic activity in the 23 March crater had increased compared to two weeks ago, and some other fumaroles were also more active. A change in wind direction shifted the volcanic plume N for much of the day and the odor of volcanic gas was noticeable in some inhabited areas. The Hazard Level remained at 2 (on a scale of 1-5).
Geologic Summary. The complex dominantly andesitic Soufrière Hills volcano occupies the southern half of the island of Montserrat. The summit area consists primarily of a series of lava domes emplaced along an ESE-trending zone. English's Crater, a 1-km-wide crater breached widely to the E, was formed during an eruption about 4,000 years ago in which the summit collapsed, producing a large submarine debris avalanche.
Block-and-ash flow and surge deposits associated with dome growth predominate in flank deposits at Soufrière Hills. Non-eruptive seismic swarms occurred at 30-year intervals in the 20th century, but with the exception of a 17th-century eruption that produced the Castle Peak lava dome, no historical eruptions were recorded on Montserrat until 1995. Long-term small-to-moderate ash eruptions beginning in that year were later accompanied by lava-dome growth and pyroclastic flows that forced evacuation of the southern half of the island and ultimately destroyed the capital city of Plymouth, causing major social and economic disruption.
Soufrière Hills Information from the Global Volcanism Program
TONGARIRO North Island (New Zealand)
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| Late on August 6, 2012, New Zealand’s Mount Tongariro erupted for the first time in 115 years, spewing a cloud of ash over North Island, closing roads, and cancelling domestic flights. A new satellite equipped with low-light imaging technology was able to capture the event in the dark of night, just an hour after it began. |
The scientists also noted that previously steaming ground at Ketetahi and Lower Te Mari crater appeared more vigorous, but there were no obvious major changes. A debris flow generated by the eruption partly filled a stream valley draining N-W from the Upper Te Mari crater area. The deposit had blocked some stream tributaries but most water diverted around the edges. Ash had slumped from the banks into the stream valley, and in other stream valleys ash has been re-mobilized in slurry flows. No lahars were generated by the eruption.
New rock falls were visible around the walls of the new vent area and Lower Te Mari craters and in some stream valley walls near the craters. This suggested that significant ground shaking took place during the eruption. The Alert Level remained at 2 (on a scale of 0-5) and the Aviation Colour Code was lowered to Yellow (second lowest on a four-color scale).
During 8-9 August seismic activity remained at a low level; only a few small events were recorded. Preliminary analysis of the ash showed that there was little to no new magma erupted. Gas analysis on 9 August revealed emissions around 2,100 tonnes per day of sulfur dioxide, 3,900 tonnes per day of carbon dioxide, and 364 tonnes per day of hydrogen sulfide, confirming the presence of magma below the volcano. During an overflight on 9 August scientists observed minor ash emissions from the vents. Seismicity continued to remain low during 10-14 August. Heavy rains on 12 August caused a lahar to cross State Highway 46, approximately 6 km W of Rangipo.
Geologic Summary: Tongariro is a large andesitic volcanic massif, located immediately NE of Ruapehu volcano, that is composed of more than a dozen composite cones constructed over a period of 275,000 years. Vents along a NE-trending zone extending from Saddle Cone (below Ruapehu volcano) to Te Mari crater (including vents at the present-day location of Ngauruhoe) were active during a several hundred year long period around 10,000 years ago, producing the largest known eruptions at the Tongariro complex during the Holocene. The youngest cone of the complex, Ngauruhoe, has grown to become the highest peak of the massif since its birth about 2500 years ago. The symmetrical, steep-sided Ngauruhoe, along with its neighbor Ruapehu to the south, have been New Zealand's most active volcanoes during historical time.
Tongariro Information from the Global Volcanism Program
WHITE ISLAND New Zealand
Geologic Summary. The uninhabited 2 x 2.4 km White Island, one of New Zealand's most active volcanoes, is the emergent summit of a 16 x 18 km submarine volcano in the Bay of Plenty about 50 km offshore of North Island. The 321-m-high island consists of two overlapping stratovolcanoes; the summit crater appears to be breached to the SE because the shoreline corresponds to the level of several notches in the SE crater wall. Throughout the short historical period beginning in 1826 the volcano has had long periods of continuous hydrothermal activity and steam release, punctuated by small-to-medium eruptions. Its activity also forms a prominent part of Maori legends. The most recent eruptive episode, which began on 7 March 2000, included the largest eruption at White Island in the past 20 years on 27 July.
White Island Information from the Global Volcanism Program
Ongoing Activity
BATU TARA Komba Island (Indonesia)
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| The Advanced Land Imager (ALI) aboard the Earth Observing-1 (EO-1) satellite captured the volcano in action on August 15, 2012. |
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 first historical eruption from Batu Tara, during 1847-52, produced explosions and a lava flow.
Batu Tara Information from the Global Volcanism Program
CLEVELAND Chuginadak Island, Alaska, USA
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| Cleveland and Tana volcanoes on Chuginadak Island in Alaska. Image taken July 26, 2012 by the EO-1 Advanced Land Imager, courtesy of the NASA Earth Observatory. |
Geologic Summary. Symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited dumbbell-shaped Chuginadak Island in the east-central Aleutians. The 1,730-m-high stratovolcano is the highest of the Islands of Four Mountains group and is one of the most active in the Aleutians. Numerous large lava flows descend its flanks. It is possible that some 18th to 19th century eruptions attributed to Carlisle (a volcano located across the Carlisle Pass Strait to the NW) should be ascribed to Cleveland. In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions from Mt. Cleveland have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks.
Cleveland Information from the Global Volcanism Program
FUEGO Guatemala
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.
Fuego Information from the Global Volcanism Program
GALERAS Colombia
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| Galeras Volcano in Southwestern Columbia. Image Credit: NOAA OSEI, CIMSS and NOAA NESDIS ORA, NOAA SEC, CIMSS and NESDIS/ORA/ARAD/ASPT |
Geologic Summary. Galeras, a stratovolcano with a large breached caldera located immediately W of the city of Pasto, is one of Colombia's most frequently active volcanoes. The dominantly andesitic Galeras volcanic complex has been active for more than 1 million years, and two major caldera collapse eruptions took place during the late Pleistocene. Longterm extensive hydrothermal alteration has affected the volcano. This has contributed to large-scale edifice collapse that has occurred on at least three occasions, producing debris avalanches that swept to the W and left a large horseshoe-shaped caldera inside which the modern cone has been constructed. Major explosive eruptions since the mid Holocene have produced widespread tephra deposits and pyroclastic flows that swept all but the southern flanks. A central cone slightly lower than the caldera rim has been the site of numerous small-to-moderate historical eruptions since the time of the Spanish conquistadors.
Galeras Information from the Global Volcanism Program
KARYMSKY Eastern Kamchatka (Russia)
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| KARYMSKY Eastern Kamchatka (Russia) so2 imagery from NASA. |
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.
Karymsky Information from the Global Volcanism Program
KILAUEA Hawaii (USA)
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| KILAUEA Hawaii (USA) |
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.
Kilauea Information from the Global Volcanism Program
NEVADO DEL RUIZ Colombia
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| This natural-color satellite image shows a burst of ash from Nevado del Ruiz on June 6, 2012. It was acquired by the Advanced Land Imager (ALI) aboard the Earth Observing-1 (EO-1) satellite. |
Satellite images showed continuing sulfur dioxide emissions. On 13 August a seismic swarm was characterized by events less than M 1, and located NE of Arenas Crater at depths between 3 and 5 km. A thin layer of ash was deposited at the observatory in Manizales. Weather conditions prevented observations of the volcano. The Alert Level remained at II (Orange; "eruption likely within days or weeks").
Geologic Summary. Nevado del Ruiz is a broad, glacier-covered volcano in central Colombia that covers >200 sq km. Three major edifices, composed of andesitic and dacitic lavas and andesitic pyroclastics, have been constructed since the beginning of the Pleistocene. The modern cone consists of a broad cluster of lava domes built within the summit caldera of an older Ruiz volcano. The 1-km-wide, 240-m-deep Arenas crater occupies the summit. Steep headwalls of massive landslides cut the flanks of Nevado del Ruiz. Melting of its summit icecap during historical eruptions, which date back to the 16th century, has resulted in devastating lahars, including one in 1985 that was South America's deadliest eruption.
Nevado del Ruiz Information from the Global Volcanism Program
POPOCATEPETL México
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| Popocatépetl |
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.
Popocatépetl Information from the Global Volcanism Program
REVENTADOR Ecuador
Geologic Summary. Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well E of the principal volcanic axis. It is a forested stratovolcano that rises above the remote jungles of the western Amazon basin. A 3-km-wide caldera breached to the E was formed by edifice collapse and is partially filled by a young, unvegetated stratovolcano that rises about 1,300 m above the caldera floor. Reventador 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.
Reventador Information from the Global Volcanism Program
SAKURA-JIMA Kyushu
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| The active volcano Sakura-Jima on the island of Kyushu, Japan is shown in the center of this radar image. |
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.
Sakura-jima Information from the Global Volcanism Program
SHIVELUCH Central Kamchatka (Russia)
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| Four volcanoes are shown in this image. Near the top, the tan cone of Shiveluch stands out against the summer-green vegetation, with the top covered by a mix of cloud and volcanic plume. The Kamchatka Volcanic ERT reported continued seismic activity at this volcano on July 13, as well as emission of a steam-gas plume. To the south, near the center of the image, lies a pair of steaming volcanoes. Klyuchevskaya is the northernmost one, and the southern is Bezymianny. The pair is shrouded in clouds, so it is impossible to tell from this image the origin of the cloud of gas and steam. The southernmost volcano in this image in Kizimen. A plume of gas and steam rises from Kizimen and is blown to the southeast. |
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 historical eruptions from Shiveluch occurred in 1854 and 1964.
Shiveluch Information from the Global Volcanism Program
SOPUTAN Sulawesi
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| SOPUTAN Sulawes |
Geologic Summary. The small conical volcano of Soputan on the southern rim of the Quaternary Tondano caldera 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.
Soputan Information from the Global Volcanism Program
TUNGURAHUA Ecuador
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| TUNGURAHUA Ecuador |
At night incandescence from the crater was observed and sounds resembling blocks rolling down the flanks were reported. On 11 August an ash-and-steam plume rose from the crater, and the next day an ash plume rose 1 km and drifted W. During 12-13 August incandescent blocks were ejected 100 m above the crater and rolled 500 m down the flanks. Roaring was heard and ash fell in Cusúa (8 km NW) and Juive (7 km NNW). On 14 August seismicity increased and was accompanied by increased emissions. Ashfall was reported in Pillate (7 km W), Cusúa, and Choglontús.
Geologic Summary. The steep-sided Tungurahua stratovolcano towers more than 3 km above its northern base. It sits ~140 km S of Quito, Ecuador's capital city, and is one of Ecuador's most active volcanoes. 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. The last major eruption took place from 1916 to 1918, although minor activity continued until 1925. The latest eruption began in October 1999 and prompted temporary evacuation of the town of Baños on the N side of the volcano.
Tungurahua Information from the Global Volcanism Program
