In connection with the upgrading of the hazard status to Alert Level 4, CVGHM stepped up its monitoring and sent a team to the field.
. On 17 April the Bureau of Meteorology in Darwin received a report from the Volcanological Survey of Indonesia of an ongoing eruption at Karangetang; however, the plume height could not be observed because of cloud cover, and no plume was seen in later satellite imagery. The Alert Level remained at 3 (on a scale of 1-4); visitors and residents were warned not to approach Karangetang within a 4-km radius. Later that day, due to decreased seismicity and a decline in the rate of lava flows, the Alert Level was lowered to 3 (on a scale of 1-4). Activity is monitored by Indonesia's Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM, or the Center of Volcanology and Geological Hazard Mitigation), and ash plumes are monitored by the Darwin VAAC (Volcanic Ash Advisory Center). An explosion on 26 May at 1747 emitted white-gray ash that reached 300 m above the crater rim before falling to the sea on the W side. The Alert Level remained at 2 throughout this period. The Darwin VAAC noted a small eruption on 3 July 2006 with an ash plume to an altitude of 3.7 km observed on satellite imagery. Ten volcanic and five tectonic earthquakes were recorded daily through 16 September. A minor explosion occurred at 2227 on 25 January and produced an ash-heavy plume that rose 700 m; ash fell into the sea W of the volcano. On 31 May at about 0200 an explosion produced a new crater at about 1,300 m elevation on the NNW flank. Incandescent blocks were reported in Kali Sesepi during 4-6 January and in Kali Batang and Beha Barat during 4-8 and 12-15 January (figure 44); they often traveled 800-1,200 m downslope. A booming noise was heard frequently throughout the report period, and during early February was sometimes accompanied by thick gray emissions up to 350 m above the crater. Courtesy of VSI. Numerous threatened towns and sub-districts were mentioned. On 26 July at 0042 a very loud explosion heralded a lava avalanche to the W and partly to the E. The next day, at 1403, another explosion produced a lava avalanche in the same direction. Felt earthquakes continuously took place with time intervals of 5 minutes or less, but the number of quakes, as recorded by a "Spindler & Hoyer" mechanical seismograph, was decreasing when compared with previous days. The volcano remained at Alert Level 3 (on a scale of 1-4). The stratovolcano contains five summit craters along a N-S line. The Alert Level remained at 2 (on a scale of 1-4).
On 7 May at 1400 an eruption that ejected incandescent material and produced a dense ash plume also generated a pyroclastic flow that traveled as far as 4 km E, leveling four houses in Kora-Kora. At 1314 on 25 November an ash plume rose to at least 500 m above the N crater and the Aviation Color Code was raised to Orange. | May
PVMBG reported that beginning at 1858 on 20 July incandescent avalanches of material from Karangetangs Main Crater traveled as far as 1 km W down the Pangi and Kinali drainages. During early July, seismographs registered small explosions, avalanches, and an average of 33 earthquakes/day. Seismicity was dominated by 572 small explosions, 451 multiphase earthquakes, and continuous lava avalanches. They further reported that this eruptive episode claimed the lives of three people. PVMBG reported that during 1-5 November lava continued to effuse from Karangetangs Main Crater (S), traveling as far as 1.5 km down the Nanitu, Pangi, and Sense drainages on the SW and W flanks. During 2-8 June, lava avalanches traveled as far as 1 km toward Batang River. Crater II produced a small ash plume to 200 m. Seismicity decreased compared to the previous week. Avalanches of incandescent material traveled 1-1.5 km SW down the Nanitu and Pangi drainages, as far as 2 km down a drainage W of Pangi, and as far as 1.8 km down the Sense drainage. On 30 May, based on a pilot observation, the Darwin VAAC reported ash at a height below 3 km drifting E; however ash was not visible on satellite imagery. PVMBG observed steam plumes rising to between 100 and 150 m above the main summit crater, and to around 25 m above the second crater during the second week of September 2014, along with incandescence at the summit. On 17 December thunderclaps were heard again and ejecta rose 100 m above the summit. Information Contacts: W. Modjo, VSI; UPI.
Based on reports from the observation post in Salili, CVGHM stated on 26 July that the occurrence of rock avalanches descending Karangetang's flanks decreased during 2013; the last one occurred on 7 July, and traveled 2 km down the Batuawang and Kahetang (E) drainages. Generally, during 21 April to 4 May, low-level ash plumes rose above South Crater, and glowing was seen up to 25 m above the crater. Having previously been lowered, the hazard status was raised from 2 to 3 on 13 July, and then to Alert Level 4 on 22 July due to increased eruptive activity. Sometimes dense white plumes rose 100-400 m above the summit. The volcano remained at Alert Level 2 (on a scale of 1-4). According to news reports, lava flows were visible and blocks originating from the lava dome traveled as far as 2 km down the flanks, along with hot gas clouds. On 21 and 22 September incandescent material traveled down multiple drainages. On 19 October at 1759 an explosion produced an ash cloud to ~750 m above the volcano. Steam plumes rose generally 50-200 m, and occasionally 400 m from the main crater.
By December 2015, incandescence was still observed at the crater from the Volcano Observatory in Salili, but steam plumes rarely exceeded 150 m. A single MODVOLC thermal anomaly pixel, was recorded on 9 December, and spikes in seismic amplitudes were recorded on 21 and 22 December. No lava flows had been observed since 25 October. The earthquakes often caused sliding of the unstable 2001 lava.
The Alert Level remained at 3 (on a scale of 1-4); visitors and residents were warned not to climb Karangetang any higher than 500 a.s.l. Incandescent avalanches from the fronts of 150-m-long lava flows traveled as far as 2.5 km E down the Batuawang and Kahetang drainages. | October
The volcano remained at Alert Level 2 (on a scale of 1-4). Activity during 2015. Discontinuous volcanic tremor was also detected. Ash plumes that rose 25-700 m were accompanied by thunderous sounds. Tectonic events dominated the seismic record (figure 4). 2021: January
Sometimes dense white plumes rose to 300 m above the summit. The VSI reported that volcanic activity continued at Karangetang. Karangetang remained at Alert Level 2 (on a scale of 1-4). The Darwin VAAC reported a continuous ash emission on 4 April 2020 that rose to 2.1 km altitude and drifted SW for a few hours before dissipating. A pyroclastic flow, triggered by collapse of a lava flow front, killed six people on 11 May. Box 735, Darwin NT, Australia; Societe de Volcanologie Geneve (SVG), B.P. Ashfall and pyroclastic flows occurred along the flanks; ash followed a similar pattern of distribution as after the 27 October explosion. Variable amounts of white and blue emissions rose as high as 100 m above Main Crater. Some of the material entered the Batang, Beha, and Keting rivers, located 300-350 m away. On 16 May an ash plume again rose to an altitude of 3.7 km a.s.l. Ash explosions and lava avalanches in July; overall activity level declines. The VSI reported that volcanic activity during 14-20 November was similar to the previous week. Based on information from a pilot report, the Darwin VAAC reported that a smoke plume was observed on 29 July at 1323 rising to an unknown height. Information Contacts: HIGP MODIS Thermal Alert System, Hawaii Institute of Geophysics and Planetology, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa (URL: http://modis.higp.hawaii.edu/); Darwin Volcanic Ash Advisory Centre (VAAC), Commonwealth Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vacc/). Ash fell on the NE flank and a lava avalanche also occurred. MODVOLC thermal alerts that were previously reported in March through 3 June 2009 (BGVN 34:05) continued through 8 November. Information Contacts: Dali Ahmad and Nia Haerani, Volcanological Survey of Indonesia (VSI), Jalan Diponegoro No. The eruption also featured a molten lava avalanche that flowed down to the Kelitu River with a maximum runout distance of ~1,250 m from the summit. In addition, a large number of shallow and deep volcanic earthquakes continued to occur. The Alert Level remained at 3 from September 2013 through 16 March 2016, when it was lowered to 2. Avalanches originating from the end of the lava flow traveled as far as 2 km down the Batang, Kahetang (E), and Nanitu drainages. PVMBG reported that during 2-8 September lava continued to effuse from Karangetangs Main Crater (S) and Dua Crater (N), traveling as far as 1.5 km down the Nanitu, Pangi, and Sense drainages on the SW flank. | September
Possible precursory signs of this activity included a darkening of the normally whitish quiescent plume beginning on 4 November.". The Alert Level remained at 2 (on a scale of 1-4). Table 10. Ashfall was reported in areas to the NW.
The Alert Level remained at 3 (on a scale of 1-4). This explosion was followed by lava avalanches and a pyroclastic flow toward the Batang river that reached as far as 2,500 m. Lava avalanches extended 1,500 m down the S and W slopes. The Alert Level remained at 3 (on a scale of 1-4); visitors and residents were warned not to approach Karangetang within a 4-km radius. | October
Vapor emission from the 1976 vents has stopped, but a solfatara ~ 50 m above the upper vent emitted a thin stream of bluish gas. By 5 February the lava flow reached over 3.5 km down the Malebuhe River drainage on the NW flank and into the ocean where a lava delta was growing with dense steam plume rising above by the 11th (figures 22-26). Ash ejection and hot lahars force evacuations; no casualities. A red glow at night and lava avalanches were reported during 9-15 June (BGVN 28:07). Seismicity also decreased, and white plumes rose up to 300 m above the craters. Incandescence from the lava dome was observed at night. Small white-colored emissions rose ~500 m above the main crater and 50-200 m above Crater II. The ash column reached 1,750 m and ash fell on the W slope, including Lehi, Mini, Kinali, and Hiung villages, while glowing material rose up to 750 m. This explosion was followed by lava avalanches towards the W and S that were accompanied by a pyroclastic flow toward the Batang river that extended 2,250 m. On 24 April, an explosion ejected ash to 750 m and ash fell eastward into the sea. Incandescent rockfalls originating from the summit and ends of the lava flows traveled hundreds of meters E toward the Kahetang and Batu Awang rivers and S towards the Keting and Batang rivers. At 0824 there was a continuous expulsion of lava which flowed S, traveling ~ 2.3 km down the Kali Batuawang river. | August
Seismicity was dominated by avalanche earthquakes. Pyroclastic flow hazard have been noticed since the 1967 explosion, then in 1984-1985, 1988, 1992 and 1996. In addition, low-level plumes rose above the main crater and crater II. | September
During the week of 9-15 June, white-colored gas emissions came from both the N and the S craters. The Karangetang volcano (1784 m above sea level) has entered an eruption period since November 25, 2018. Between 16 October and 26 November 2004, thermal anomalies were again frequent. The following report covers activity during February to mid-December 2000. On 1 December, incandescent rockslides traveled 250 m S towards the Bahembang River, 750 m W towards the Beha Timur River, and 500-1,500 m S towards the Keting River. Seismicity remained elevated with earthquake distributions similar to the previous week. No further activity was reported until 3 November 2009. Seismicity was dominated by multi-phase earthquakes and signals characteristic of avalanches, with rare volcanic earthquakes.
Sometimes dense white plumes rose to 200 m above the summit. Karangetang remained at Alert Level 3 (on a scale of 1-4). | November
Bull Volc Surv Indonesia, 109: 1-48. During the report period, there was a decrease in the number of earthquakes, and seismicity was dominated by 125 avalanche earthquakes. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Agence France-Presse (URL: http://www.afp.com/); Arnold Binas, Toronto, Canada (URL: http://www.summitpost.org/user_page.php?user_id=42443, http://www.flickr.com/photos/hshdude/collections/72157600584144439/). Based on a pilot observation, the Darwin VAAC reported that on 24 May an ash plume from Karangetang rose to an altitude of 3.7 km (12,000 ft) a.s.l. During 4-7 December incandescent blocks appeared in Kali Sesepe, traveling 1,000-1,500 m down from the summit. | April
Volcanological Survey of Indonesia, 1986. The following additional information is from a report by scientists from the Volcano Observation Section, Geological Survey of Indonesia. 5h journey by ferry from Manado. Ash plume from crater II rose 25 m. Medium-thick ash plume from main crater reached 100 m; light plume also observed reaching 10 m. Thin ash plume from crater II rose 50 m. One explosion event. Throughout the reporting period PVMBG noted that moderate seismicity occurred, which included both shallow and deep volcanic earthquakes. Seismicity decreased, but continued to be dominated by signals characteristic of avalanches. Eruption in August 2010 isolated 20,000 residents and caused four deaths. The Center of Volcanology and Geological Hazard Mitigation (CVGHM) reported that during 21-23 March incandescent material from Karangetang was ejected 50-75 m above the crater. The VSI reported that during 12-18 December, activity increased at Karangetang in comparison to the previous week. The eruption was followed by lava avalanches that traveled S down the Batu Awang river, and E down the Kahetang river to a maximum run-out distance of ~500 m. Another explosion occurred on 26 May at 1747; it produced an ash cloud to a height of 300 m above the crater that drifted to the W. Karangetang remained at Alert Level 2 (on a scale of 1-4). It last erupted in August [ see story below ], killing four people. Karangetang remained active during 9 September to 6 October, with low-level ash clouds rising above South and North craters, lava flowing from the crater, and volcanic tremor being recorded. In a VONA issued on 2 February, PVMBG reported an eruption at Karangetang, characterized by crater incandescence and an ash plume that rose 600 m. The Aviation Color Code was raised from Unassigned to Yellow. The Alert Level remained at 2 (on a scale of 1-4). Table 1. A coeval Strombolian eruption cloud rose 200 m. Ashfall occurred W of the volcano, coating Pahe, Lehi, Mini, and Kinali villages. Residents of the village of Dame and part of the population of the township of Tatahadeng were advised to maintain a high level of alertness to the dangers of pyroclastic flows and lava flows. | May
. Incandescence from the lava dome was observed at night. On 2 December, the Alert Level was raised to 3 due to the continuation of elevated seismicity, the appreciable run-out distances of incandescent rockslides, and the height of incandescent material ejected from the summit. The flow front continued to advance 5-10 m/day. Incandescent lava avalanches traveled toward Kahetang, Batuawang, Batang, and Beha rivers. Indonesia, Karangetang : Level of activity at level III (SIAGA). Karangetang remained at Alert Level 3 (on a scale of 1-4). Inhabitants downslope of the lava flow were alerted, including the villages of Kola, Bola, and Kopi. At the beginning of February, the main crater of Karangetang (also known as Api Siau) produced a light-colored ash emission that rose 250-350 m, while Crater II emitted a lighter ash plume to a height of 75-100 m. At night the ash column glowed red to a height of 10-25 m. Similar activity continued through May; variable-density emissions from the main crater rose to a maximum height of 500 m, those from Crater II rose up to 150 m, red illumination was visible up to 75 m at night, and rumbling was heard intermittently through May.