Active volcanoes in the world: April 6 – 12, 2016

New activity/unrest was observed at 6 volcanoes between April 6 and 12, 2016. During the same period, ongoing activity was observed at 16 volcanoes.

New activity/unrest: Kerinci, Indonesia  | Klyuchevskoy, Central Kamchatka (Russia)  | Langila, New Britian (Papua New Guinea)  | Pavlof, United States  | Popocatepetl, Mexico  | Sangay, Ecuador.

Ongoing activity: Aira, Kyushu (Japan)  | Alaid, Kuril Islands (Russia)  | Chirpoi, Kuril Islands (Russia)  | Colima, Mexico  | Dukono, Halmahera (Indonesia)  | Fuego, Guatemala  | Karymsky, Eastern Kamchatka (Russia)  | Kilauea, Hawaiian Islands (USA)  | Masaya, Nicaragua  | Momotombo, Nicaragua  | Sheveluch, Central Kamchatka (Russia)  | Sinabung, Indonesia  | Soputan, Sulawesi (Indonesia)  | Telica, Nicaragua  | Tengger Caldera, Eastern Java (Indonesia)  | Zhupanovsky, Eastern Kamchatka (Russia).

New activity/unrest

Kerinci, Indonesia
1.697°S, 101.264°E, Summit elev. 3800 m

Based on a pilot observation and reports from PVMBG, the Darwin VAAC reported that on 10 April ash plumes from Kerinci rose to altitudes of 4-4.3 km (13,000-14,000 ft) a.s.l. and drifted NE and E.

Geologic summary: The 3800-m-high Gunung Kerinci in central Sumatra forms Indonesia's highest volcano and is one of the most active in Sumatra. Kerinci is capped by an unvegetated young summit cone that was constructed NE of an older crater remnant. The volcano contains a deep 600-m-wide summit crater often partially filled by a small crater lake that lies on the NE crater floor, opposite the SW-rim summit of Kerinci. The massive 13 x 25 km wide volcano towers 2400-3300 m above surrounding plains and is elongated in a N-S direction. The frequently active Gunung Kerinci has been the source of numerous moderate explosive eruptions since its first recorded eruption in 1838.

Klyuchevskoy, Central Kamchatka (Russia)
56.056°N, 160.642°E, Summit elev. 4754 m

KVERT reported that Strombolian explosions and gas-and-steam emission continued to be observed at Klyuchevskoy during 3-8 April. Satellite images showed a thermal anomaly during 1 and 5-7 April. The Aviation Color Code remained at Yellow.

Geologic summary: Klyuchevskoy (also spelled 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. It 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 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 the 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.

Langila, New Britian (Papua New Guinea)
5.525°S, 148.42°E, Summit elev. 1330 m

Based on analyses of satellite imagery, the Darwin VAAC reported that during 6-7 April ash plumes from Langila rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 55 km NE and E.

Geologic summary: Langila, one of the most active volcanoes of New Britain, consists of a group of four small overlapping composite basaltic-andesitic cones on the lower eastern flank of the extinct Talawe volcano. Talawe is the highest volcano in the Cape Gloucester area of NW New Britain. A rectangular, 2.5-km-long crater is breached widely to the SE; Langila volcano was constructed NE of the breached crater of Talawe. An extensive lava field reaches the coast on the north and NE sides of Langila. Frequent mild-to-moderate explosive eruptions, sometimes accompanied by lava flows, have been recorded since the 19th century from three active craters at the summit of Langila. The youngest and smallest crater (no. 3 crater) was formed in 1960 and has a diameter of 150 m.

Pavlof, United States
55.417°N, 161.894°W, Summit elev. 2493 m

On 6 April AVO stated that the eruption at Pavlof had ended; during the previous week satellite images indicated no signs of ash emissions or lava effusion, and seismicity was at low levels. Thermal anomalies at the summit were occasionally visible though likely indicating cooling processes of previously erupted lava. AVO lowered the Aviation Color Code to Yellow and Volcano Alert Level to Advisory.

Geologic summary: The most active volcano of the Aleutian arc, Pavlof is a 2519-m-high Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and its twin volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, Pavlof has been frequently active in historical time, typically producing Strombolian to Vulcanian explosive eruptions from the summit vents and occasional lava flows. The active vents lie near the summit on the north and east sides. The largest historical eruption took place in 1911, at the end of a 5-year-long eruptive episode, when a fissure opened on the N flank, ejecting large blocks and issuing lava flows.

Popocatepetl, Mexico
19.023°N, 98.622°W, Summit elev. 5426 m

During 6-12 April there were 38-136 emissions from Popocatépetl and as many as six explosions detected daily; some emissions corresponded with increased crater incandescence. Periods of low-amplitude harmonic tremor were detected during 6-8 April. An explosion at 0111 on 9 April produced a gas-and-ash plume that rose 1.5 km above the crater and drifted NE, and ejected incandescent fragments 300 m away onto the E flank. The Alert Level remained at Yellow, Phase Two.

Geologic summary: Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5426 m 70 km SE of Mexico City to form North America's 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 400 x 600 m wide crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas to the south. The modern volcano was constructed south of the late-Pleistocene to Holocene El Fraile cone. Three major plinian eruptions, the most recent of which took place about 800 CE, have occurred from Popocatépetl since the mid Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since precolumbian time.

Sangay, Ecuador
2.005°S, 78.341°W, Summit elev. 5286 m

Based on satellite images, the Washington VAAC reported that on 6 April an ash plume from Sangay drifted over 35 km NW.

Geologic summary: The isolated Sangay volcano, located east of the Andean crest, is the southernmost of Ecuador's volcanoes, and its most active. The dominantly andesitic volcano has been in frequent eruption for the past several centuries. The steep-sided, 5230-m-high glacier-covered volcano grew within horseshoe-shaped calderas of two previous edifices, which were destroyed by collapse to the east, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. It towers above the tropical jungle on the east side; on the other sides flat plains of ash have been sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of a historical eruption was in 1628. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The almost constant activity has caused frequent changes to the morphology of the summit crater complex.

Ongoing activity

Aira, Kyushu (Japan)
31.593°N, 130.657°E, Summit elev. 1117 m

JMA reported that during 4-8 April the seismic network at Aira Caldera’s Sakurajima volcano detected four explosions at Showa Crater, generating ash plumes that rose as high as 3.5 km above the crater rim. One of the explosions, recorded at 1333 on 6 April, produced an ash plume that rose 3.5 km. An explosion at 1922 on 8 April generated an ash plume that rose 3.7 km and ejected cinders as far as 1.3 km away. Small-scale explosions occurred at Minamidake summit crater on 5, 6, and 9 April. The Alert Level remained at 3 (on a 5-level scale).

Geologic summary: The Aira caldera in the northern half of Kagoshima Bay contains the post-caldera Sakurajima volcano, one of Japan's most active. Eruption of the voluminous Ito pyroclastic flow accompanied formation of the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera was formed during the early Holocene in the NE corner of the Aira caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim of Aira caldera and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4850 years ago, after which eruptions took place at Minamidake. 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.

Alaid, Kuril Islands (Russia)
50.861°N, 155.565°E, Summit elev. 2285 m

KVERT reported that moderate activity at Alaid continued during 1-8 April. Satellite images showed an intense daily thermal anomaly over the volcano. A gas-and-steam plume containing minor amounts of ash drifted about 40 km SW on 1 April. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Geologic summary: The highest and northernmost volcano of the Kuril Islands, 2285-m-high Alaid is a symmetrical stratovolcano when viewed from the north, but has a 1.5-km-wide summit crater that is breached widely to the south. Alaid is the northernmost of a chain of volcanoes constructed west of the main Kuril archipelago and rises 3000 m from the floor of the Sea of Okhotsk. Numerous pyroclastic cones dot the lower flanks of basaltic to basaltic-andesite Alaid volcano, particularly on the NW and SE sides, including an offshore cone formed during the 1933-34 eruption. Strong explosive eruptions have occurred from the summit crater beginning in the 18th century. Reports of eruptions in 1770, 1789, 1821, 1829, 1843, 1848, and 1858 were considered incorrect by Gorshkov (1970). Explosive eruptions in 1790 and 1981 were among the largest in the Kuril Islands during historical time.

Chirpoi, Kuril Islands (Russia)
46.525°N, 150.875°E, Summit elev. 742 m

SVERT reported that satellite images detected a thermal anomaly over Snow, a volcano of Chirpoi, during 4-5 and 7 April. 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. 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.

Colima, Mexico
19.514°N, 103.62°W, Summit elev. 3850 m

Based on satellite images, wind data, webcam images, and notices from the Mexico City MWO, the Washington VAAC reported that during 6-8 April ash plumes from Colima rose to altitudes of 5.8-6.1 km (19,000-20,000 ft) a.s.l. and drifted NNE and NE.

Geologic summary: The Colima volcanic complex is the most prominent volcanic center of the western Mexican Volcanic Belt. It consists of two southward-younging volcanoes, Nevado de Colima (the 4320 m high point of the complex) on the north and the 3850-m-high historically active Volcán de Colima at the south. A group of cinder cones of late-Pleistocene age is located on the floor of the Colima graben west and east of the Colima complex. Volcán de Colima (also known as Volcán Fuego) is a youthful stratovolcano constructed within a 5-km-wide caldera, breached to the south, that has been the source of large debris avalanches. Major slope failures have occurred repeatedly from both the Nevado and Colima cones, and have produced a thick apron of debris-avalanche deposits on three sides of the complex. Frequent historical eruptions date back to the 16th century. Occasional major explosive eruptions (most recently in 1913) have destroyed the summit and left a deep, steep-sided crater that was slowly refilled and then overtopped by lava dome growth.

Dukono, Halmahera (Indonesia)
1.693°N, 127.894°E, Summit elev. 1229 m

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 6-12 April ash plumes from Dukono rose to altitudes of 2.1-2.7 km (7,000-9,000 ft) a.s.l. and drifted as far as 110 km in multiple directions.

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 north-flank cone of Gunung Mamuya. This complex volcano presents a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.

Fuego, Guatemala
14.473°N, 90.88°W, Summit elev. 3763 m

In a special bulletin from 7 April, INSIVUMEH reported that moderate and strong explosions at Fuego generated ash plumes that rose 850-1,050 m and drifted 15 km SW. The explosions were heard in areas as far as 20 km away, and were accompanied by shock waves that vibrated structures within a 12-km radius. Rumbling was heard in Santa Lucia Cotzulmaguapa (20 km SW). Ash fell in local areas including Panimache and Panimache II (8 km SW), Morelia (9 km SW), and Sangre de Cristo (8 km WSW). During 7-8 April gray ash plumes from explosions rose as high as 950 m and drifted 15 km W and SW. Rumbling noises and detectable shock waves continued. Incandescent material was ejected 250 m high and generated avalanches down the Las Lajas (SE), Trinidad (S), Santa Teresa (W), and Taniluyá (SW) drainages. A high level of activity continued during 9-12 April; five to six explosions per hour were detected during 9-10 April. Dense ash plumes rose over 1 km high and drifted 15 km SW. Ashfall was noted in multiple villages including San Pedro Yepocapa (8 km N), Panimaché, and Sangre de Cristo. Shock waves vibrated structures within 15 km, and rumbling was heard 30 km away. At night block avalanches were seen reaching vegetated areas on the flanks. During 11-12 April incandescent material was ejected 200 m high, causing avalanches down the Las Lajas, Trinidad, Santa Teresa, Taniluyá, and Ceniza (SSW) drainages.

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 3763-m-high Fuego and its twin volcano to the north, Acatenango. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at Acatenango. In contrast to the mostly andesitic Acatenango, eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous historical eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows.

Karymsky, Eastern Kamchatka (Russia)
54.049°N, 159.443°E, Summit elev. 1513 m

KVERT reported that moderate activity at Karymsky continued during 1-8 April. Satellite images showed a weak thermal anomaly over the volcano on 1 and 6 April. 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 during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-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.

Kilauea, Hawaiian Islands (USA)
19.421°N, 155.287°W, Summit elev. 1222 m

HVO reported that seismicity beneath Kilauea's summit, upper East Rift Zone, and Southwest Rift Zone was at background levels during 6-12 April. The lava lake continued to circulate and spatter in the Overlook vent. The lava lake dropped during a deflationary event that began on 4 April and, by 7 April, was 52 m below the crater floor, the deepest it has been since 30 December 2015. On 7 April at 0147 a large part of the inner crater wall fell into the lake. The deflationary event lasted for about four days. Webcams recorded outgassing from multiple spatter cones on the Pu'u 'O'o Crater floor. The June 27th NE-trending lava flow continued to be active within 7.6 km NE of Pu'u 'O'o Crater.

Geologic summary: Kilauea volcano, which overlaps the east flank of the massive Mauna Loa shield volcano, has been Hawaii's most active volcano during historical time. Eruptions of Kilauea are prominent in Polynesian legends; written documentation extending back to only 1820 records frequent summit and flank lava flow eruptions that were interspersed with periods of long-term lava lake activity that lasted until 1924 at Halemaumau crater, within the summit caldera. The 3 x 5 km caldera was formed in several stages about 1500 years ago and during the 18th century; eruptions have also originated from the lengthy East and SW rift zones, which extend to the sea on both sides of the volcano. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1100 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.

Masaya, Nicaragua
11.984°N, 86.161°W, Summit elev. 635 m

INETER reported that during 6-12 April the lava lake on the floor of Masaya's Santiago crater remained visible. RSAM values were at high levels and gas emissions were low.

Geologic summary: Masaya is one of Nicaragua's most unusual and most active volcanoes. It lies within the massive Pleistocene Las Sierras pyroclastic shield volcano and is a broad, 6 x 11 km basaltic caldera with steep-sided walls up to 300 m high. The caldera is filled on its NW end by more than a dozen vents that erupted along a circular, 4-km-diameter fracture system. The twin volcanoes of Nindirí and Masaya, the source of historical eruptions, were constructed at the southern end of the fracture system and contain multiple summit craters, including the currently active Santiago crater. A major basaltic plinian tephra erupted from Masaya about 6500 years ago. Historical lava flows cover much of the caldera floor and have confined a lake to the far eastern end of the caldera. A lava flow from the 1670 eruption overtopped the north caldera rim. Masaya has been frequently active since the time of the Spanish Conquistadors, when an active lava lake prompted attempts to extract the volcano's molten "gold." Periods of long-term vigorous gas emission at roughly quarter-century intervals cause health hazards and crop damage.

Momotombo, Nicaragua
12.422°N, 86.54°W, Summit elev. 1297 m

INETER reported that three explosions at Momotombo during 5-6 April ejected incandescent material onto the flanks and produced gas-and-ash plumes that rose 500 m above the crater. During 6-7 April there were 27 small explosions for a total of 438 explosions detected since 1 December 2015. The explosions ejected some incandescent material, and generated ash plumes that rose 200 m and drifted SW. RSAM values were low during 5-12 April.

Geologic summary: Momotombo is a young, 1297-m-high stratovolcano that rises prominently above the NW shore of Lake Managua, forming one of Nicaragua's most familiar landmarks. Momotombo began growing about 4500 years ago at the SE end of the Marrabios Range and consists of a somma from an older edifice that is surmounted by a symmetrical younger cone with a 150 x 250 m wide summit crater. Young lava flows from Momotombo have flowed down the NW flank into the 4-km-wide Monte Galán caldera. The youthful cone of Momotombito forms a 391-m-high island offshore in Lake Managua. Momotombo has a long record of strombolian eruptions, punctuated by occasional larger explosive activity. The latest eruption, in 1905, produced a lava flow that traveled from the summit to the lower NE base. A small black plume was seen above the crater after an April 10, 1996 earthquake, but later observations noted no significant changes in the crater. A major geothermal field is located on the southern flank of the volcano.

Sheveluch, Central Kamchatka (Russia)
56.653°N, 161.36°E, Summit elev. 3283 m

KVERT reported that during 1-8 April lava-dome extrusion onto Sheveluch’s N flank was accompanied by strong fumarolic activity, dome incandescence, ash explosions, and hot avalanches. Satellite images showed an intense daily thermal anomaly over the dome, and an ash plume that drifted 65 km SE on 2 April. The Aviation Color Code remained at Orange.

Geologic summary: The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 cu km volcano is one of Kamchatka's largest and most active volcanic structures. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera.

Sinabung, Indonesia
3.17°N, 98.392°E, Summit elev. 2460 m

Based on satellite images and information from PVMBG, the Darwin VAAC reported that during 6, 8-10, and 12 April ash plumes from Sinabung rose to altitudes of 3.3-4.8 km (11,000-16,000 ft) a.s.l. and drifted SW, W, and WNW.

On 10 April BNPB reported that the eruption at Sinabung has not shown any signs of ceasing since the onset of activity in September 2013. Activity remained high, characterized by almost daily lava extrusion and pyroclastic flows, and high levels of seismicity. Four events on 10 April generated ash plumes that rose as high as 2 km. BNPB noted that although there were no new evacuees that day, 9,322 people (2,592 families) remained in 10 evacuation centers. Many families awaited relocation; 1,212 people had already been permanently relocated to new homes. The Alert Level remained at 4 (on a scale of 1-4); the public was reminded to stay outside of a 3-km radius. People within 7 km of the volcano in the SSE sector, within 6 km in the ESE sector, and within 4 km in the NNE sector should remain evacuated.

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 in 1912. No confirmed historical eruptions were recorded prior to explosive eruptions during August-September 2010 that produced ash plumes to 5 km above the summit.

Soputan, Sulawesi (Indonesia)
1.112°N, 124.737°E, Summit elev. 1785 m

PVMBG reported that during 4-11 April diffuse white plumes from Soputan rose as high as 100 m above the crater and drifted E. Seismicity was dominated by signals indicating avalanches and emissions; avalanche signals became less intense as compared to the previous week. A few volcanic and shallow volcanic earthquakes were detected during 6 and 9-10 April. The Alert Level was lowered to 2 (on a scale of 1-4); residents and tourists were advised not to approach the craters within a radius of 4 km.

Geologic summary: The Soputan stratovolcano on the southern rim of the Quaternary Tondano caldera on the northern arm of Sulawesi Island is one of Sulawesi's most active volcanoes. The youthful, largely unvegetated volcano rises to 1784 m and is located SW of Riendengan-Sempu, which some workers have included with Soputan and Manimporok (3.5 km ESE) as a volcanic complex. It was constructed at the southern end of a SSW-NNE trending line of vents. 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.

Telica, Nicaragua
12.602°N, 86.845°W, Summit elev. 1061 m

INETER reported that during 6-11 April micro-seismicity at Telica remained high and lava in a vent on the crater floor was observed. Gas emissions were at low to moderate levels and RSAM values were low.

Geologic summary: Telica, one of Nicaragua's most active volcanoes, has erupted frequently since the beginning of the Spanish era. This volcano group consists of several interlocking cones and vents with a general NW alignment. Sixteenth-century eruptions were reported at symmetrical Santa Clara volcano at the SW end of the group. However, its eroded and breached crater has been covered by forests throughout historical time, and these eruptions may have originated from Telica, whose upper slopes in contrast are unvegetated. The steep-sided cone of 1061-m-high Telica is truncated by a 700-m-wide double crater; the southern crater, the source of recent eruptions, is 120 m deep. El Liston, immediately SE of Telica, has several nested craters. The fumaroles and boiling mudpots of Hervideros de San Jacinto, SE of Telica, form a prominent geothermal area frequented by tourists, and geothermal exploration has occurred nearby.

Tengger Caldera, Eastern Java (Indonesia)
7.942°S, 112.95°E, Summit elev. 2329 m

Based on satellite images, wind data, and ground reports from PVMBG, the Darwin VAAC reported that during 6-8 and 10-12 April ash plumes from Tengger Caldera's Bromo cone rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted SW, WSW, and W.

Geologic summary: The 16-km-wide Tengger caldera is located at the northern end of a volcanic massif extending from Semeru volcano. The massive volcanic complex dates back to about 820,000 years ago and consists of five overlapping stratovolcanoes, each truncated by a caldera. Lava domes, pyroclastic cones, and a maar occupy the flanks of the massif. The Ngadisari caldera at the NE end of the complex formed about 150,000 years ago and is now drained through the Sapikerep valley. The most recent of the calderas is the 9 x 10 km wide Sandsea caldera at the SW end of the complex, which formed incrementally during the late Pleistocene and early Holocene. An overlapping cluster of post-caldera cones was constructed on the floor of the Sandsea caldera within the past several thousand years. The youngest of these is Bromo, one of Java's most active and most frequently visited volcanoes.

Zhupanovsky, Eastern Kamchatka (Russia)
53.589°N, 159.15°E, Summit elev. 2899 m

KVERT reported that at Zhupanovsky no activity was observed after an explosion on 24 March. A very weak thermal anomaly was detected over the volcano in satellite images on 1 and 10 April. The Aviation Color Code was lowered to Yellow won 13 April.

Geologic summary: The Zhupanovsky volcanic massif consists of four overlapping stratovolcanoes along a WNW-trending ridge. The elongated volcanic complex was constructed within a Pliocene-early Pleistocene caldera whose rim is exposed only on the eastern side. Three of the stratovolcanoes were built during the Pleistocene, the fourth is Holocene in age and was the source of all of Zhupanovsky's historical eruptions. An early Holocene stage of frequent moderate and weak eruptions from 7000 to 5000 years before present (BP) was succeeded by a period of infrequent larger eruptions that produced pyroclastic flows. The last major eruption took place about 800-900 years BP. Historical eruptions have consisted of relatively minor explosions from the third cone.

Source: GVP