Active volcanoes in the world: December 25 – December 31, 2013

New activity was observed at 3 volcanoes between December 25 and 31. During the same period, ongoing activity was observed at 9 volcanoes.

New activity/unrest: | Nishimo-shima, Japan | San Miguel, El Salvador | Sinabung, Sumatra (Indonesia)

Ongoing activity: | Chirinkotan, Kuril Islands | Chirpoi, Kuril Islands (Russia) | Dukono, Halmahera | Etna, Sicily (Italy) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kliuchevskoi, Central Kamchatka (Russia) | Shiveluch, Central Kamchatka (Russia) | Suwanose-jima, Ryukyu Islands and Kyushu

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

NISHIMO-SHIMA, Izu, Volcano, and Mariana Islands (Japan) 
27.274°N, 140.882°E; summit elev. 38 m

According to a news article, since mid-December lava flows from the newly formed Niijima island expanded NE towards Nishino-shima, and on 24 December the two islands joined. The Niijima area was about 500 m long and 450 m wide.

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

SAN MIGUEL, El Salvador 
13.434°N, 88.269°W; summit elev. 2130 m

According to news articles, an explosive eruption at San Miguel that began at 1030 on 29 December prompted an evacuation of 1,400-2,600 people. A dense ash plume rose from the crater. Based on wind data, the Washington VAAC reported that the ash plume rose to an altitude of 9.7 km (32,000 ft) a.s.l. and drifted ENE at higher altitudes and W at lower altitudes.

SNET reported that sulfur dioxide flux was 637 tonnes per day on 29 December and 1,244 tonnes per day on 30 December. During 30-31 December seismicity decreased significantly. Through the morning of 31 December emissions had consisted of gas and slight amounts of ash that drifted WSW.

Geologic summary: The symmetrical cone of San Miguel volcano, one of the most active in El Salvador, rises from near sea level to form one of the country's most prominent landmarks. A broad, deep crater that has been frequently modified by historical eruptions (recorded since the early 16th century) caps the truncated summit of the towering volcano, which is also known locally as Chaparrastique. Radial fissures on the flanks of the basaltic volcano have fed a series of fresh lava flows, including several erupted during the 17th-19th centuries that reached beyond the base of the volcano on the N, W, and SE sides. The SE-flank lava flows are the largest and form broad sparsely vegetated lava fields.

SINABUNG, Sumatra (Indonesia) 
3.17°N, 98.392°E; summit elev. 2460 m

PVMBG reported that seismicity at Sinabung increased during 21-26 December and indicated rising magma and lava-dome growth. Observers in Ndokum Siroga, about 8.5 km away, noted dense white plumes rising 70-1,200 m above the crater. Roaring was also periodically heard. A lava dome in the North Crater, visible on 24 December, was 56 m high and 210 m wide. During 25-26 December plumes were white and gray, and rose 300-400 m above the crater. On 26 December the lava-dome volume was estimated to be over 1 million cubic meters, with a growth rate of 3.5 cubic meters per second. The Alert Level remained at 4 (on a scale of 1-4). Visitors and tourists were prohibited from approaching the crater within a radius of 5 km.

On 30 December Badan Nacional Penanggulangan Bencana (BNPB) reported that the number of displaced people reached 19,126 (5, 979 families). They also noted that activity at Sinabung had increased. Collapsing parts of the lava dome generated block-and-ash flows as well as pyroclastic flows which traveled as far as 3.5 km down the SE flank. Explosions and pyroclastic flows generated ash plumes that rose at least 6 km above the crater.

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

Ongoing activity

CHIRINKOTAN, Kuril Islands 
48.980°N, 153.480°E; summit elev. 724 m

SVERT reported that a thermal anomaly over Chirinkotan was observed in satellite images during 25-26 December. Cloud cover obscured views on the other days during 23-30 December. The Aviation Color Code remained at Yellow.

Geologic summary: The small, mostly unvegetated 3-km-wide island of Chirinkotan occupies the far end of an E-W-trending volcanic chain that extends nearly 50 km west of the central part of the main Kuril Islands arc. Chirinkotan is the emergent summit of a volcano that rises 3000 m from the floor of the Kuril Basin. A small 1-km-wide caldera about 300-400 m deep is open to the SE. Lava flows from a cone within the breached crater reached the north shore of the island. Historical eruptions have been recorded at Chirinkotan since the 18th century. Fresh lava flows also descended the SE flank of Chirinkotan during an eruption in the 1880s that was observed by the English fur trader Captain Snow.

CHIRPOI, Kuril Islands (Russia) 
46.525°N, 150.875°E; summit elev. 742 m

SVERT reported that a thermal anomaly over Snow, a volcano of Chirpoi, was detected in satellite images on 26 December. Cloud cover obscured views on the other days during 23-30 December. The Aviation Color Code remained at 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.

DUKONO, Halmahera 
1.68°N, 127.88°E; summit elev. 1335 m

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 25-27 December ash plumes from Dukono rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 35-75 km NNW, N, and SE.

Geologic summary: Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the N-flank cone of Gunung Mamuya. Dukono is a complex volcano presenting a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of Dukono's summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.

ETNA, Sicily (Italy) 
37.734°N, 15.004°E; summit elev. 3330 m

INGV reported that on 28 December a helicopter overflight of Etna's New Southeast Crater (NSEC) revealed a crater floor partially covered with snow, and weak fumarolic activity on the N, W, and S crater rims. During the early morning hours on 29 December a camera recorded weak and sporadic incandescence from NSEC. Strong pulsating degassing also occurred at Northeast Crater. At 1115 NSEC produced a single Strombolian explosion, accompanied by an ash plume that rose 1 km and drifted E. After the explosion mild Strombolian activity continued and then progressively intensified in the evening. Frequent powerful explosions from two vents located within the crater were audible in a vast sector around the volcano. Diffuse ash plumes drifted NE. Contemporaneously, two lava flows are active, one from a vent on the E flank of the NSEC cone, and the second, fed directly from the crater, traveled down the NE flank of the cone.

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.

KARYMSKY, Eastern Kamchatka (Russia) 
54.05°N, 159.45°E; summit elev. 1536 m

KVERT reported that Vulcanian and Strombolian activity at Karymsky continued during 20-27 December. Satellite images detected a bright thermal anomaly on the volcano daily. 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 24-30 December HVO reported that the circulating lava lake occasionally 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 N and S portions of the crater floor. The 6.3-km-long Kahauale’a 2 lava flow, fed by the NE spatter cone, was active with scattered break-out flows and burned the forest N of Pu'u 'O'o.

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.

KLIUCHEVSKOI, Central Kamchatka (Russia) 
56.057°N, 160.638°E; summit elev. 4850 m

On 27 December KVERT reported that the explosive eruption at Kliuchevskoi had finished; the last strong explosion was detected on 17 December. Video images showed gas-and-steam plumes rising from the volcano during the previous weeks. Satellite images continued to detect thermal anomalies over the summit and the lava flow on the SW flank. The Aviation Color Code was lowered to Yellow.

Geologic summary: Kliuchevskoi is Kamchatka's highest and most active volcano. Since its origin about 6000 years ago, the beautifully symmetrical, 4835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. Kliuchevskoi rises above a saddle NE of sharp-peaked Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred at Kliuchevskoi during the past roughly 3000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 m and 3600 m elevation. 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 numerous major explosive and effusive eruptions from flank craters.

SHIVELUCH, Central Kamchatka (Russia)
56.653°N, 161.360°E; summit elev. 3283 m

KVERT reported that during 20-27 December a newer lava dome extruded onto the NW part of Shiveluch's older lava dome. Lava-dome extrusion was accompanied by hot avalanches, incandescence, and fumarolic activity. Moderate ash explosions generated ash plumes that rose to altitudes of 4-5 km (13,100-16,400) a.s.l. A thermal anomaly was detected daily in satellite images. 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.

SUWANOSE-JIMA, Kyushu
29.635°N, 129.716°E; summit elev. 799 m

Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 26-30 December. Explosions during 27-28 December generated plumes that rose to an altitude over 1.5 km (5,000 ft) a.s.l. and drifted SE.

Geologic summary: The 8-km-long, spindle-shaped island of Suwanose-jima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. Only about 50 persons live on the sparsely populated island. The summit of the volcano is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanose-jima, one of Japan's most frequently active volcanoes, was in a state of intermittent strombolian activity from On-take (Otake), the NE summit crater, that began in 1949 and lasted until 1996, after which periods of inactivity lengthened. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of On-take collapsed forming a large debris avalanche and creating the horseshoe-shaped Sakuchi caldera, which extends to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884.

Source: GVP