Active volcanoes in the world: February 27 – March 5, 2013

Active volcanoes in the world: February 27 – March 5, 2013

This week, 9 volcanoes were noticed to have new activity and ongoing activity was reported for same number of volcanoes. This report covers active volcanoes in the world recorded from February 27 – March 5, 2013 based on Smithsonian/USGS criteria.

New activity/unrest: | Cleveland, Chuginadak Island | Etna, Sicily (Italy) | Fuego, Guatemala | Pacaya, Guatemala | Reventador, Ecuador | Rincón de la Vieja, Costa Rica | Stromboli, Aeolian Islands (Italy) | Tungurahua, Ecuador | White Island, New Zealand

Ongoing activity: | Chirpoi, Kuril Islands (Russia) | Fuego, Guatemala | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Ruapehu, North Island (New Zealand) | Sakura-jima, Kyushu | Shiveluch, Central Kamchatka (Russia) | Tolbachik, Central 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 2300 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


 

CLEVELAND, Chuginadak Island


52.825°N, 169.944°W; summit elev. 1730 m

AVO reported that during 27 February-5 March clouds obscured satellite views of Cleveland's lava dome. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

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.

 

ETNA, Sicily (Italy)


37.734°N, 15.004°E; summit elev. 3330 m

Sezione di Catania - Osservatorio Etneo reported that seismic activity at Etna's Bocca Nuova Crater (BN) gradually increased at night during 26-27 February. Copious, puffing emission of dense vapor from BN observed at sunrise slowly grew more energetic over the next few hours. Between 1030 and 1045, the volcanic tremor amplitude rapidly rose; at the same time an eruption column largely composed of vapor formed and hot material was ejected. The plume contained moderate amounts of reddish-brown volcanic ash, mostly during 1215-1220 and 1314-1316, which led to the fall of small quantities of very fine ash on the SE flank between Zafferana and Santa Venerina. These ash emissions likely resulted from collapse or sliding of unstable material on the steep inner crater wall; the eruptive vent, which lies in the SE part of the crater, is leaning against the wall and the rapid accumulation of pyroclastic deposits in that area might have facilitated collapses.

During the phase of most intense eruptive activity, INGV staff carrying out fieldwork in the summit area, noted that volcanic bombs fell outside the crater rim onto the SW flank of the central cone. Intense explosive activity was also observed within the Voragine (VOR), which since early October 1999 had not exhibited magmatic activity. The activity began to diminish around 1320, evident from a reduction in the volcanic tremor amplitude; at 1430, the episode was essentially over, even though strong degassing continued at both BN and VOR. During the evening of 27 February vigorous Strombolian activity in VOR was reported by observers on the W and E flanks. Minor and discontinuous Strombolian activity also occurred at BN which often launched incandescent volcanic bombs up to 150 m above the crater rim. The activity continued through the night, into at least early 28 February, when NSEC also started showing signs of renewed activity after more than four days of repose.

Weak explosive activity and sporadic weak ash emissions at New SE Crater (NSEC) were observed during the early morning hours of 28 February. Weak Strombolian activity in the W part of the NSEC appeared at 0917. Thirteen minutes later Strombolian activity was occurring at the main vent in the center of NSEC. Contemporaneously, the volcanic tremor amplitude started to rise. During the following hour, eruptive activity gradually increased, while the volcanic tremor amplitude increased rapidly; at 1030, at least three vents were erupting including the former "pittino" to the W, in the saddle between the old SEC cone and NSEC cone. This activity generated a dense gas plume containing modest quantities of ash. At 1040 lava flowed through the through the deep breach cutting the SE crater rim; 25 minutes later, explosive activity increased dramatically and lava fountains rose about 100 m above the crater rim. From 1115 on, frequent powerful explosions generated visible shock waves and heavily showered the NSEC cone with large volcanic bombs. The activity intensified further between 1117 and 1122, accompanied by a conspicuous cloud of vapor and brown ash issued from the saddle between the two SEC cones. This cloud marked the progressive collapse of a large portion of  the saddle, which destroyed nearly all of the SW flank of the NSEC cone, and parts of the E flank of the old SEC cone. Voluminous amounts of lava flowed from the deep notch left by the collapse, expanding first S and then SE, in the direction of the Belvedere monitoring station. Lava was also emitted from the eruptive vents at the base of the NSEC cone; this lava mixed with the flow emitted directly from the NSEC toward SE.

Sustained lava fountaining, with intense pyroclastic fallout and the generation of a huge cloud of gas and ash, continued at maximum intensity for about 20 minutes. The ash cloud drifted E, leading to abundant ash and scoria fall in the Milo-Fornazzo and Giarre-Riposto areas. At 1142 the activity started to diminish, although dense clouds of vapor and grayish-brown ash were emitted from the collapsed saddle area. At about 1150, the activity at the "pittino" became phreatomagmatic; vapor and ash were emitted and hot, wet blocks that formed spectacular vapor trails were ejected. Shortly after 1200, explosive activity at the NSEC ceased, whereas lava emission continued from the collapsed saddle area as well as from the SE flank of the NSEC cone, at a slowly diminishing rate. The lava flows continued to advance during the night of 28 February-1 March, and ceased sometime during 1 March. Strombolian activity within the VOR continued without significant variations, and was observed by INGV staff during a field visit on the morning of 1 March, at least through 1500 on 3 March.

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 BC. Historical lava flows cover much of the surface of this massive basaltic stratovolcano, the highest and most voluminous in Italy. 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. Flank eruptions, typically with higher effusion rates, occur less frequently and originate from fissures that open progressively downward from near the summit. A period of more intense intermittent explosive eruptions from Etna's summit craters began in 1995. The active volcano is monitored by the Instituto Nazionale di Geofisica e Volcanologia (INGV) in Catania.

 

FUEGO, Guatemala


14.473°N, 90.880°W; summit elev. 3763 m

INSIVUMEH reported that during 28 February-1 March explosions from Fuego produced ash plumes that rose less than 250 m and lava flows traveled 300 m S down the Trinidad drainage. Activity increased on 3 March characterized by Strombolian explosions, and lava flows that traveled 1.3 km down the Trinidad drainage and 200 m SW down the Taniluya drainage.  Ash plumes rose almost 350 m above the crater and drifted 10 km S. The eruption ended the next day, after 52 hours of activity. White and blue fumarolic plumes rose from the crater. During 4-5 March incandescence 100 m above the crater was observed, and ash plumes rose 200 m and drifted E. Avalanches descended the Taniluya drainage.

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.

 

PACAYA, Guatemala


14.381°N, 90.601°W; summit elev. 2552 m

INSIVUMEH reported that on 5 March a gas-and-ash plume rose from Pacaya's MacKenney cone and drifted 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 volcano constructed on the southern rim of the 14 x 16 km Pleistocene Amatitlan caldera. A cluster of dacitic lava domes occupies the caldera floor. The Pacaya massif includes the Cerro Grande lava dome and a younger volcano to the SW. Collapse of Pacaya volcano about 1,100 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. During the past several decades, activity at Pacaya has consisted of frequent Strombolian eruptions with intermittent lava flow extrusion on the flanks of MacKenney cone, punctuated by occasional larger explosive eruptions.

 

REVENTADOR, Ecuador


0.077°S, 77.656°W; summit elev. 3562 m

According to the Washington VAAC, the IG reported that on 2 March lava flows were observed, and a gas-and-ash plume rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted SW. About an hour later a pilot observed an ash plume that rose to the same altitude. No ash plumes were identified in satellite imagery, however a weak thermal anomaly was observed during 2-3 March.

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.

 

RINCON DE LA VIEJA, Costa Rica


10.830°N, 85.324°W; summit elev. 1916 m

OVSICORI-UNA received reports at 0530 on 26 February of pulsing white plumes rising from Rincon de la Vieja's active crater about every four minutes. The seismic records showed no signals associated with a phreatic eruption or sudden gas output. Cloud cover prevented views of the active crater during an overflight later that day, however clear views of the N and S flanks and areas SW showed no changes.

Geologic summary: Rincón de la Vieja, the largest volcano in NW Costa Rica, is a remote volcanic complex in the Guanacaste Range. The volcano consists of an elongated, arcuate NW-SE-trending ridge that was constructed within the 15-km-wide early Pleistocene Guachipelín caldera, whose rim is exposed on the south side. Rincón de la Vieja, sometimes known as the "Colossus of Guanacaste," has an estimated volume of 130 cu km and contains at least 9 major eruptive centers. Activity has migrated to the SE, where the youngest-looking craters are located. The twin cone of 1916-m-high Santa María volcano, the highest peak of the Rincón complex, is located at the eastern end of a smaller, 5-km-wide caldera and has a 500-m-wide crater. A plinian eruption producing the 0.25 cu km Río Blanca tephra about 3500 years ago was the last major magmatic eruption from the volcano. All subsequent eruptions, including numerous historical eruptions possibly dating back to the 16th century, have been from the prominent crater containing a 500-m-wide acid lake (known as the Active Crater) located ENE of Von Seebach crater.

 

STROMBOLI, Aeolian Islands (Italy)


38.789°N, 15.213°E; summit elev. 924 m

Stromboli again produced small lava overflows from the crater terrace on the afternoon of 27 February through the following night, after an interval of 10 days of normal Strombolian activity. A second episode of lava overflow started on the evening of 1 March and ceased the next afternoon. Both overflows were fed by continuous spattering from vent N2, which lies at the top of a hornito perched on the N rim of the crater terrace.

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 historical time. The small, 926-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 active summit vents are located at the head of the Sciara del Fuoco, a horseshoe-shaped scarp formed as a result of slope failure that extends to below sea level and funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild Strombolian explosions, sometimes accompanied by lava flows, have been recorded at Stromboli since Roman times.

 

TUNGURAHUA, Ecuador


1.467°S, 78.442°W; summit elev. 5023 m

IG reported that seismicity at Tungurahua increased on 28 February. The next day an increase in the number of long-period earthquakes was accompanied by small explosions, roaring, and ash emissions. At around 1600 on 1 March a plume of water vapor and gas containing small amounts of ash rose a few hundred meters above the crater and drifted WNW. Ashfall was reported in areas on the SW flank including Choglontús (SW) and Manzano (8 km SW). On 2 March an explosion at 1106 produced noises from blocks rolling down the flanks. Instruments detected deformation on the NW flank. Cloud cover during 1-2 March inhibited visual observations.

At night during 2-3 March incandescent blocks were ejected from the crater and rolled 300 m down the flanks. Seismicity again increased on 3 March. Ash plumes rose from the crater and produced ashfall in Manzano and Penipe (15 km SW). Cloud cover prevented views on 4 March, however ashfall was reported in Manzano. On 5 March explosions produced an ash plume that rose 1-1.5 km above the crater and drifted W.

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.

 

WHITE ISLAND, New Zealand


37.52°S, 177.18°E; summit elev. 321 m

On 4 March GeoNet Data Centre reported that during the previous week a small ash cone surrounded by a small moat of water had been built in the crater that formerly contained the hot lake. Ash emissions had ceased, therefore the Aviation Colour Code was lowered to Yellow and the Volcanic Alert Level was lowered to 1 (on a scale of 0-5). Seismic tremor levels were low, possibly because of the lack of water involvement in the current activity. Scientists aboard an overflight flight on 26 February measured around 600 tonnes per day of sulfur dioxide, and 1,950 tonnes per day of carbon dioxide, similar to other measurements made since the start of 2013.

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.

 

Ongoing activity


 

CHIRPOI, Kuril Islands (Russia)


46.525°N, 150.875°E; summit elev. 742 m

SVERT reported that weak steam-and-gas emissions from Snow, a volcano of Chirpoi, were observed on 25 February, and 1 and 3 March. A thermal anomaly was detected in satellite images on 28 February and 3 March. Cloud cover prevented observations of the volcano on other days during 25 February-4 March. The Aviation Color Code was Yellow.

Geologic summary: Chirpoi, a small island lying between the larger islands of Simushir and Urup, contains a half dozen volcanic edifices constructed within an 8-9 km wide, partially submerged caldera. The southern rim of the caldera is exposed on nearby Brat Chirpoev Island. Two volcanoes on Chirpoi Island have been historically active. The symmetrical Cherny volcano, which forms the 691 m high point of the island, erupted twice during the 18th and 19th centuries. The youngest volcano, Snow, originated between 1770 and 1810. It is composed almost entirely of lava flows, many of which have reached the sea on the southern coast. No historical eruptions are known from 742-m-high Brat Chirpoev, but its youthful morphology suggests recent strombolian activity.

 

FUEGO, Guatemala


14.473°N, 90.880°W; summit elev. 3763 m

INSIVUMEH reported that during 28 February-1 March explosions from Fuego produced ash plumes that rose less than 250 m. Lava flows traveled 300 m S down the Trinidad drainage. Activity increased on 3 March, characterized by Strombolian explosions, and lava flows that traveled 1.3 km down the Trinidad drainage and 200 m SW down the Taniluya drainage.  Ash plumes rose almost 350 m above the crater and drifted 10 km S. The eruption ended the next day, after 52 hours of activity. White and blue fumarolic plumes rose from the crater. During 4-5 March incandescence 100 m above the crater was observed, and ash plumes rose 200 m and drifted E. Avalanches descended the Taniluya drainage.

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.

 

KARYMSKY, Eastern Kamchatka (Russia)


54.05°N, 159.45°E; summit elev. 1536 m

KVERT reported that moderate seismic activity at Karymsky was detected during 22 February-1 March. Satellite imagery showed a thermal anomaly on the volcano during 21 and 25-28 February. 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 27 February-5 March HVO reported that the circulating lava lake periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. The plume from the vent continued to deposit variable amounts of ash, spatter, and Pele's hair onto nearby areas.

At Pu'u 'O'o Crater, glow emanated from spatter cones on the SE part of the crater floor, from a spatter cone at the NW edge of the floor, and from a perched lava lake on the NE part of the floor. Multiple lava flows from the NE spatter cone, collectively and informally called the Kahauale'a flow, traveled across the NE flank of Pu'u 'O'o cone to the cone's base and advanced 2.5 km NE over older flows. A branch also traveled S, just S of Pu'u Kahauale'a, and started fires in the kipuka. Lava flows were active above the pali (5 km SE of Pu'u 'O'o) and in a 1-km-wide area on the coastal plain. To the W, a 350-m-wide lava flow advanced towards the coast and produced scattered breakouts. Web cameras recorded steam plumes from lava sporadically entering the ocean at multiple locations.

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.

 

KIZIMEN, Eastern Kamchatka (Russia)


55.130°N, 160.32°E; summit elev. 2376 m

KVERT reported that during 22 February-1 March moderate seismic activity continued at Kizimen. Video data showed that lava continued to extrude from the summit, producing summit incandescence, strong gas-and-steam activity, and hot avalanches on the W and E flanks. Satellite images detected a daily thermal anomaly over the volcano. The Aviation Color Code remained at Orange.

Geologic summary: Kizimen is an isolated, conical stratovolcano that is morphologically similar to Mount St. Helens prior to its 1980 eruption. The summit of Kizimen consists of overlapping lava domes, and blocky lava flows descend the flanks of the volcano, which is the westernmost of a volcanic chain north of Kronotsky volcano. The 2,376-m-high Kizimen was formed during four eruptive cycles beginning about 12,000 years ago and lasting 2,000-3,500 years. The largest eruptions took place about 10,000 and 8300-8400 years ago, and three periods of longterm lava-dome growth have occurred. The latest eruptive cycle began about 3,000 years ago with a large explosion and was followed by lava-dome growth lasting intermittently about 1,000 years. An explosive eruption about 1,100 years ago produced a lateral blast and created a 1.0 x 0.7 km wide crater breached to the NE, inside which a small lava dome (the fourth at Kizimen) has grown. A single explosive eruption, during 1927-28, has been recorded in historical time.

 

RUAPEHU, North Island (New Zealand)


39.28°S, 175.57°E; summit elev. 2797 m

On 5 March, GeoNet reported that monitoring of the Ruapehu Crater Lake showed that temperatures at depth remained above background levels but had started a declining trend. Gas data from January and February showed emission rates of 15-25 tonnes per day of sulfur dioxide and around 650 tonnes per day carbon dioxide; these are within the usual range of emissions measured at Ruapehu. Seismicity remained low, characterized by weak volcanic tremor and some shallow earthquakes. Areas of discoloration in the lake, sometimes observed during the previous few weeks, are relatively common and thought to reflect internal lake convection processes. Scientists speculated that there was a partial blockage between the deep and shallow systems causing the lake temperature to remain steady; the relatively low temperature of Crater Lake, 22-25°C since March 2012, is one of the longest periods of low lake temperatures recorded. The Volcanic Alert Level remained at 1 (signs of volcano unrest) and the Aviation Colour Code remained at Yellow.

Geologic summary: Ruapehu, one of New Zealand's most active volcanoes, is a complex stratovolcano constructed during at least four cone-building episodes. The 110 cu km volcanic massif is elongated in a NNE-SSW direction and is surrounded by another 100 cu km ring plain of volcaniclastic debris. A single historically active vent, Crater Lake, is located in the broad summit region, but at least five other vents on the summit and flanks have been active during the Holocene. Frequent mild-to-moderate explosive eruptions have occurred in historical time from the Crater Lake vent. Lahars produced by phreatic eruptions from the summit crater lake are a hazard to a ski area on the upper flanks and to river valleys below the volcano.

 

SAKURA-JIMA, Kyushu


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 27 February-3 March and 5 March generated ash plumes that rose to altitudes of 1.8-3.7 km (6,000-12,000 ft) a.s.l. and drifted S, SE, and E. A pilot observed an ash plume that rose to an altitude of 4.3 km (14,000 ft) a.s.l. on 28 February. JMA reported that 10 explosions from Showa Crater were detected during 1-4 March, and ejected tephra fell at most 1.3 km from the crater.

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 22 February-2 March a viscous lava flow effused on the E flank of Shiveluch's lava dome, accompanied by hot avalanches, incandescence, and fumarolic activity. Satellite imagery showed a daily thermal anomaly on the lava dome. Based on video images, KVERT reported that explosions produced a gas-and-ash plume that rose to an altitude of 9 km (29,500 ft) a.s.l. on 4 March, and an ash plume rose 4 km (13,100 ft) a.s.l. and drifted 20 km SE on 6 March. 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 historical eruptions from Shiveluch occurred in 1854 and 1964.

 

TOLBACHIK, Central Kamchatka (Russia)


55.830°N, 160.330°E; summit elev. 3682 m

KVERT reported that the S fissure along the W side of Tolbachinsky Dol, a lava plateau on the SW side of Tolbachik, continued to produce very fluid lava flows during 22 February-1 March that traveled to the W, S, and E sides of the plateau. Cinder cones continued to grow on the fissure. Gas-and-ash plumes rose to an altitude of 3.5 km (11,500 ft) a.s.l. and drifted in multiple directions. A very large thermal anomaly on the N part of Tolbachinsky Dol was visible daily in satellite imagery. The Aviation Color Code remained at Orange.

Geologic summary: The massive Tolbachik basaltic volcano is located at the southern end of the dominantly andesitic Kliuchevskaya volcano group. The Tolbachik massif is composed of two overlapping, but morphologically dissimilar volcanoes. The flat-topped Plosky Tolbachik shield volcano with its nested Holocene Hawaiian-type calderas up to 3 km in diameter is located east of the older and higher sharp-topped Ostry Tolbachik stratovolcano. The summit caldera at Plosky Tolbachik was formed in association with major lava effusion about 6500 years ago and simultaneously with a major southward-directed sector collapse of Ostry Tolbachik volcano. Lengthy rift zones extending NE and SSW of the volcano have erupted voluminous basaltic lava flows during the Holocene, with activity during the past two thousand years being confined to the narrow axial zone of the rifts. The 1975-76 eruption originating from the SSW-flank fissure system and the summit was the largest historical basaltic eruption in Kamchatka.

Source: Global Volcanism Program

Featured image: David Amsler - CC BY 2.0

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