This week, 7 volcanoes were noticed to have new activity, whereas ongoing activity was reported for 13 volcanoes. This report covers active volcanoes in the world recorded from January 23 – January 29, 2013 based on Smithsonian/USGS criteria.
New activity/unrest: | Etna, Sicily (Italy) | Karkar, Northeast of New Guinea (SW Pacific) | Rabaul, New Britain | Reventador, Ecuador | Sangay, Ecuador | Stromboli, Aeolian Islands (Italy) | White Island, New Zealand
Ongoing activity: | Batu Tara, Komba Island (Indonesia) | Chirpoi, Kuril Islands (Russia) | Copahue, Central Chile-Argentina border | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Kliuchevskoi, Central Kamchatka (Russia) | Manam, Northeast of New Guinea (SW Pacific) | Paluweh, Lesser Sunda Islands (Indonesia) | Sakura-jima, Kyushu | Santa María, Guatemala | 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.
ETNA, Sicily (Italy)
37.734°N, 15.004°E; summit elev. 3330 m
Sezione di Catania – Osservatorio Etneo reported that two episodes of Strombolian activity from Etna’s Bocca Nuova Crater occurred during the evenings of 16 and 18 January. Both began with a sudden increase in volcanic tremor amplitude. Poor weather conditions prevented direct observations; the only visible evidence was a bright glow illuminating the clouds covering the summit. On 18 January some clasts were ejected onto the S outer slope of the central summit cone.
On the early morning of 20 January volcanic tremor amplitude again rose, and was much more pronounced at the EBEL station about 700 m from the New Southeast Crater (NSEC) than at the ECPN station much closer to Bocca Nuova. Contemporaneously, there were reports of glow illuminating the clouds over the summit of Etna. Seismic and infrasonic data analyses suggested that the activity occurred at NSEC and consisted of mild Strombolianexplosions, which ceased a few hours later.
The next episode began at 22 January. Tremor rapidly rose at 1840 again producing a stronger signal at the EBEL station. Glow from Strombolian activity was first recorded by a camera at 1856; the activity then became more clearly visible and the Strombolian explosions became more frequent. Incandescent bombs were ejected as high as 100 m above the crater rim. The strongest explosions were followed by abundant fallout of coarse-grained tephraonto the flanks of the NSEC cone. Eruptive activity continued for nearly 12 hours with minor fluctuations. Noises produced by the explosions were audible to residents on the E flank. At about 0600 on 23 January the tremor amplitude decreased and the last explosion visible on camera footage was recorded at 0635. During the hour following, a few small, sporadic puffs of vapor mixed with volcanic ash rose from the crater and drifted E.
The two episodes of Strombolian activity at the New Southeast Crater during 20 and 22-23 January represented the first emission of new magmatic products after a quiet interval of nearly nine months. During the past few months, signs of a possible reactivation of the crater were observed, starting with a dull glow coming from within the crater on 22 November 2012 and a series of small vapor and ash emissions during 25-27 December 2012. A short-lived episode of intense glow occurred on the evening of 3 January 2013.
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.
KARKAR, Northeast of New Guinea (SW Pacific)
4.649°S, 145.964°E; summit elev. 1839 m
Based on analyses of satellite imagery and wind data analyses, the Darwin VAAC reported that an ash plume from Karkar rose to an altitude of 4.3 km (14,000 ft) a.s.l. and drifted less than 40 km NE.
Geologic summary: Karkar is a 19 x 25 km wide, forest-covered island that is truncated by two nested summit calderas. The 5.5-km-wide outer caldera was formed during one or more eruptions, the last of which occurred 9000 years ago. The eccentric 3.2-km-wide inner caldera was formed sometime between 1500 and 800 years ago. Parasitic cones are present on the northern and southern flanks of basaltic-to-andesitic Karkar volcano; a linear array of small cones extends from the northern rim of the outer caldera nearly to the coast. Most historical eruptions, which date back to 1643, have originated from Bagiai cone, a pyroclastic cone constructed within the steep-walled, 300-m-deep inner caldera. The floor of the caldera is covered by young, mostly unvegetated andesitic lava flows.
RABAUL, New Britain
4.271°S, 152.203°E; summit elev. 688 m
RVO reported that during 23-24 January variable emissions at Rabaul mostly consisted of white vapor plumes, although following explosions gray plumes rose 600 m above the crater. Some roaring and rumbling noises were noted. Five explosions were detected between 0656 and 0859 on 24 January; these explosions produced light grayash plumes that rose as high as 1 km above sea level. After the explosion at 0656 white plumes also rose from the crater. All plumes drifted E and ESE. Several explosions were detected between 1630 on 24 January and 0232 on 25 January, although seismicity remained at a low level. White vapor plumes and occasional light gray ash plumes rose from the crater and drifted E and SE.
About five explosions occurred between 1947 on 26 January and 0414 on 27 January, producing plumes that drifted ESE. An explosion at 1000 on 27 January produced a dense, billowing, light gray ash plume that rose a few hundred meters above sea level and drifted ESE. Ash emissions continued until 1500, followed by white vapor emissions. Six explosions were detected overnight, possibly generating ash plumes that drifted E and ESE.
During the morning of 28 January white vapor plumes rose from the crater. At 1003 an explosion produced a dense, billowing, gray ash plume; ash emissions continued from the next hour and then turned to white vapor. Two explosions occurred at 1323 and 1816, generating ash plumes and sub-continuous emissions for one hour and 15-20 minutes, respectively. Plumes again drifted E and ESE. White plumes rose from the crater afterwards through 29 January, but an explosion at 1723 generated a dense, billowing ash plume followed by a short period of sub-continuous emissions.
Geologic summary: The low-lying Rabaul caldera on the tip of the Gazelle Peninsula at the NE end of New Britain forms a broad sheltered harbor. The outer flanks of the 688-m-high asymmetrical pyroclastic shield volcano are formed by thick pyroclastic-flow deposits. The 8 x 14 km caldera is widely breached on the E, where its floor is flooded by Blanche Bay. Two major Holocene caldera-forming eruptions at Rabaul took place as recently as 3,500 and 1,400 years ago. Three small stratovolcanoes lie outside the northern and NE caldera rims. Post-caldera eruptions built basaltic-to-dacitic pyroclastic cones on the caldera floor near the NE and western caldera walls. Several of these, including Vulcan cone, which was formed during a large eruption in 1878, have produced major explosive activity during historical time. A powerful explosive eruption in 1994 occurred simultaneously from Vulcan and Tavurvur volcanoes and forced the temporary abandonment of Rabaul city.
0.077°S, 77.656°W; summit elev. 3562 m
IG reported that in the morning of 22 January tremor at Reventador increased significantly and signals indicating rockfalls were detected. Explosions were heard during the afternoon and evening that same day. After an explosion in the crater a gas-and-steam plume was observed rising 1.5 km above the crater. Lava flows traveled down the SW and N flanks. The lava dome had grown at least 100 m above the crater rim.
During 23-29 January seismicity remained high. Cloud cover mostly prevented visual observations; during 22-23 January lava flow were visible at night, and on 24 January a steam-and-ash plume rose 2 km. Gas plumes rose as high as 1 km and drifted NW and W on 29 January.
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.
2.002°S, 78.341°W; summit elev. 5230 m
Based on a pilot report, analyses of satellite images, and information from the Guayaquil MWO, the WashingtonVAAC reported that a possible eruption from Sangay before 1210 on 25 January may have produced ash plumes. Cloud cover prevented satellite observations of emissions during 25-26 January, although a weak thermal anomaly was detected.
Geologic summary: The isolated Sangay volcano, located E of the Andean crest, is the southernmost of Ecuador’s volcanoes, and its most active. It has been in frequent eruption for the past several centuries. The steep-sided, 5,230-m-high glacier-covered volcano grew within horseshoe-shaped calderas of two previous edifices, which were destroyed by collapse to the E, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. Sangay towers above the tropical jungle on the E side; on the other sides flat plains of ash from the volcano have been sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an historical eruption was in 1628. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The more or less constant eruptive activity has caused frequent changes to the morphology of the summit crater complex.
STROMBOLI, Aeolian Islands (Italy)
38.789°N, 15.213°E; summit elev. 924 m
On 15 January Sezione di Catania – Osservatorio Etneo reported that overflowing lava from vents lying just below the rim of the northernmost explosive vent on Stromboli’s crater terrace generated small lava flows that traveled down the N and NW sectors of the Sciara del Fuoco. Landslides caused by the sliding and rolling of loose rock material on the steep slope of the Sciara del Fuoco sometimes accompanied the lava flows. At night during 15-16 January, effusive activity ceased, then only very small lava overflows were observed on the evening of 17 January and during the night of 19-20 January.
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.
WHITE ISLAND, New Zealand
37.52°S, 177.18°E; summit elev. 321 m
At 1600 on 24 January the GeoNet Data Centre reported that seismicity at White Island had changed during the previous 20-30 hours; volcanic tremor decreased while hybrid earthquakes appeared, which suggested magmamovement within the volcano. The Aviation Colour Code was raised to Orange (second highest on a four-color scale) and the Volcanic Alert Level remained at 1 (on a scale of 0-5).
On 25 January scientists conducted an overflight to measure gas emissions and found that the levels were similar to those measured on 19 December 2012. The scientists observed vigorous mud geysering in the crater lake. Seismicity remained above background levels.
On 29 January continuous tremor that had been recorded during the past few weeks changed to intermittent tremor, which remained strong. The crater lake was drying out and frequent bursts of mud, steam, and gas were still vigorous; mud and rock were ejected tens of meters out of the lake area. Steam-and-gas plumes that rose from the crater were visible from the Bay of Plenty coastline. GNS Science’s past monitoring of the island showed that weakash eruptions had often followed drying out of the same type of mud-filled lake.
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 shorthistorical 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.
BATU TARA, Komba Island (Indonesia)
7.792°S, 123.579°E; summit elev. 748 m
Based on analyses of satellite imagery and wind data, the Darwin Volcanic Ash Advisory Centre (VAAC) reported that during 27-28 January ash plumes from Batu Tara rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted 37 km NE and E.
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 historicaleruption from Batu Tara, during 1847-52, produced explosions and a lava flow.
CHIRPOI, Kuril Islands (Russia)
46.525°N, 150.875°E; summit elev. 742 m
SVERT reported that a thermal anomaly and steam-and-gas emissions from Snow, a volcano of Chirpoi, on 8 January, were detected on 21, 23, and 25 January; cloud cover prevented observations of the volcano on other days during 22-28 January.
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 thecaldera 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 oflava 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.
COPAHUE, Central Chile-Argentina border
37.85°S, 71.17°W; summit elev. 2997 m
OVDAS-SERNAGEOMIN reported that during 22-28 January the web camera near Copahue recorded white gas plumes rising 100-800 m above the crater and drifting E and SE. Seismicity remained at low levels. An explosion at 2355 on 22 January produced a gas plume (with no ash) that rose 1.45 km above the crater. The Alert Level remained at Orange.
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.
KARYMSKY, Eastern Kamchatka (Russia)
54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that weak-to-moderate seismic activity at Karymsky was detected during 18-25 January, indicating that possible ash plumes rose to an altitude of 2.5 km (8,200 ft) a.s.l. Satellite imagery showed a thermal anomaly on the volcano during 20-23 January; cloud cover prevented observations on the other days. The Aviation Color Code remained at Orange.
Geologic summary: Karymsky, the most active volcano of Kamchatka’s eastern volcanic zone, is a symmetricalstratovolcano 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 23-29 January 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, andPele’s hair onto nearby areas. on 23 January a portion of the W vent wall fell into the lake. The lake level was 35 m below the Halema’uma’u crater floor on 23 January and 38 m below the floor on 28 January.
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 circulating lava lake on the NE part of the floor. Lava flows were active in a 1-km-wide area on the coastal plain. Web cameras recorded steam plumes from lava sporadically entering the ocean at multiple locations. On most days lava flows from multiple vents were active on the crater floor. On 25 and 26 January pilots confirmed that a lava flow remained active on the E flank of Pu’u ‘O’o cone.
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 18-25 January moderate seismic activity continued at Kizimen. Video data showed that lava continued to extrude from the summit onto the E and SE flanks. Summit incandescence, strong gas-and-steam activity, and occasional hot avalanches on the W and E flanks accompanied the process. 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.
KLIUCHEVSKOI, Central Kamchatka (Russia)
56.057°N, 160.638°E; summit elev. 4835 m
KVERT reported that during 18-25 January video footage and satellite imagery showed Strombolian explosions at Kliuchevskoi, along with crater incandescence and gas-and-steam emissions. Views from satellite were obscured by cloud cover. The Aviation Color Code remained at Orange.
Geologic summary: Kliuchevskoi is Kamchatka’s highest and most active volcano. Since its origin about 7,000 years ago, the beautifully symmetrical, 4,835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. More than 100 flank eruptions, mostly on the NE and SE flanks of the conical volcano between 500 m and 3,600 m elevation, have occurred during the past 3,000 years. The morphology of its 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included major explosive and effusive events from flank craters.
MANAM, Northeast of New Guinea (SW Pacific)
4.080°S, 145.037°E; summit elev. 1807 m
Based on observations of satellite imagery and wind data analyses, the Darwin VAAC reported that an ash plume from Manam rose to an altitude of 3 km (10,000 ft) a.s.l. on 28 January and drifted 22 km E. The next day an ash plume drifted 93 km NE, and then later another ash plume drifted 55 km NE at an altitude of 4.3 km (14,000 ft) a.s.l.
Geologic summary: The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country’s most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical 1807-m-high basaltic-andesitic stratovolcano to its lower flanks. These “avalanche valleys,” regularly spaced 90 degrees apart, channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Two summit craters are present; both are active, although most historical eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE avalanche valley. Frequent historical eruptions, typically of mild-to-moderate scale, have been recorded at Manam since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas.
PALUWEH, Lesser Sunda Islands (Indonesia)
8.32°S, 121.708°E; summit elev. 875 m
Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 29 January ash plumes from Paluweh rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted less than 20 km ENE.
Geologic summary: Paluweh volcano, also known as Rokatenda, forms the 8-km-wide island of Paluweh N of the volcanic arc that cuts across Flores Island. Although the volcano rises about 3,000 m above the sea floor, its summit reaches only 875 m above sea level. The broad irregular summit region contains overlapping craters up to 900 m wide and several lava domes. Several flank vents occur along a NW-trending fissure. The largest historical eruption of Paluweh occurred in 1928, when a strong explosive eruption was accompanied by landslide-induced tsunamis and lava-dome emplacement.
31.585°N, 130.657°E; summit elev. 1117 m
JMA reported that during 21-25 January explosions from Sakura-jima’s Showa Crater ejected tephra as far as 1.3 km from the crater. Crater incandescence was detected on 21 January.
Based on information from JMA, the Tokyo VAAC reported that explosions during 23-29 January generated plumes that rose to altitudes of 1.2-2.4 km (4,000-8,000 ft) a.s.l. and drifted E and SE. Pilots observed ash plumes drifting SE at altitudes of 3 and 2.4 km (10,000 and 8,000 ft) a.s.l. on 27 and 28 January, respectively.
Geologic summary: Sakura-jima, one of Japan’s most active volcanoes, is a post-caldera cone of the Aira calderaat 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 depositedash 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.
SANTA MARIA, Guatemala
14.756°N, 91.552°W; summit elev. 3772 m
Based on analysis of satellite imagery, the Washington VAAC reported that on 23 January a diffuse ash plume from Santa María drifted SSE and SSW. INSIVUMEH reported that during 24-27 January explosions from the Santiaguito lava-dome complex produced ash plumes that rose 800-900 m. White vapor plumes rose 200-400 m and drifted W, SW, and E during 26-29 January. Active lava flows produced avalanches during 28-29 January.
Geologic summary: Symmetrical, forest-covered Santa María volcano is one of a chain of large stratovolcanoesthat rises dramatically above the Pacific coastal plain of Guatemala. The stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a large, 1-km-wide crater, which formed during a catastrophic eruption in 1902 and extends from just below the summit to the lower flank. The renowned Plinian eruption of 1902 followed a long repose period and devastated much of SW Guatemala. The large 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, accompanied by almost continuous minor explosions and periodiclava extrusion, larger explosions, pyroclastic flows, and lahars.
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 18-25 January a viscouslava flow effused on the E flank of Shiveluch’s lava dome, accompanied by hot avalanches, incandescence, andfumarolic activity. Satellite imagery showed a daily thermal anomaly on the lava dome. The Aviation Color Coderemained at Orange.
Geologic summary: The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group 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 18-25 January that traveled to the W and S sides of Tolbachinsky Dol. Four cinder cones continued to grow on the S fissure above Krasny cone. Gas-and-ash plumes rose to an altitude of 4 km (13,100 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 dominantlyandesitic 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-typecalderas 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.
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