Agung

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  • Indonesia
  • Indonesia
  • Stratovolcano
  • 2018 CE
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 8.343°S
  • 115.508°E

  • 2997 m
    9830 ft

  • 264020
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

Most Recent Weekly Report: 13 June-19 June 2018 Citation IconCite this Report


PVMBG reported that at 1105 on 13 June an event at Agung produced a dense ash plume that rose around 2 km above the crater rim and drifted SW and W. Based on analysis of the seismic data, the event lasted two minutes and 12 seconds. Another event was detected at 2115 on 15 June, though foggy conditions prevented estimations of the ash plume height; ash fell in areas W, including in Puregai (7 km W). The Alert Level remained at 3 (on a scale of 1-4) and the 4-km-radius exclusion zone was unchanged.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


Most Recent Bulletin Report: January 2018 (BGVN 43:01) Citation IconCite this Report


New eruption after 54 years; extensive pre-eruption seismicity precedes ash emission on 21 November 2017

A large explosive and effusive eruption lasting about 11 months during 1963-64 at Indonesia's Mount Agung on Bali produced voluminous ashfall, devastating pyroclastic flows that caused extensive damage, and over 1,000 fatalities. The volcano remained largely quiet until renewed seismicity began in August 2017, the prelude to a new eruptive episode, which started in late November 2017 and is ongoing. Self and Rampino (2012) and Fontijn et al. (2015) published detailed summaries of historical activity at Agung prior to this new episode; a brief summary of their work is provided.

Information about the new eruptive episode comes from Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG), also known as the Indonesian Center for Volcanology and Geological Hazard Mitigation (CVGHM), Badan Nasional Penanggulangan Bencana (BNPB) which is the National Board for Disaster Management, the Darwin Volcanic Ash Advisory Center (VAAC), and various sources of satellite data. The first two months of this new episode, through December 2017, are discussed in this report.

Summary of 1963-64 eruption. The February 1963 to January 1964 eruption, Indonesia's largest and most devastating eruption of the twentieth century, was a multi-phase explosive and effusive event that produced both basaltic andesite tephra and andesite lava (Self and Rampino, 2012). After a few days of felt earthquakes on 16 and 17 February 1963, explosive activity began at the summit on 18 February. This was followed the next day by the effusion of about 0.1 km3 of andesite lava which was extruded until 17 March 1963, when a large explosive eruption generated pyroclastic density currents (PDCs) and lahars that devastated wide areas N, SW, and SE of the volcano (figure 1) (Fontijn et al, 2015).

Figure (see Caption) Figure 1. Map of Gunung Agung and vicinity, eastern Bali, showing the extent of the 1963 lava flow (cross-hatched), pyroclastic flow deposits (stippled), and lahar deposits (dark shading) of the 1963–1964 eruption (after unpublished map courtesy of Indonesian Volcanological Survey). Sg is Siligading village, where many fatalities occurred. Reproduced from Self and Rampino (2012, figure 3).

Explosive activity continued intermittently until a second explosive phase of similar intensity occurred two months later, beginning on 16 May 1963 with reported ash plumes reaching 10 km above the 3-km-high summit (figure 2). This phase produced the greatest proportion of the pyroclastic flow material from the eruption and led to additional death and destruction in villages at the foot of the volcano (Self and Rampino, 2012). Explosive outbursts continued intermittently until 17 January 1964. The total death toll of the eruption was estimated between 1,100 and 1,900 (see references in Fontijn et al., 2015). A total estimated volume of erupted magma was ca 0.4 km3 (Self and Rampino, 2012).

Figure (see Caption) Figure 2. Photograph reported to be of the 16 May 1963 eruption column at Agung; the view is from the SW, perhaps near Rendang (shown on figure 1). Photo courtesy of the family of Denis Mathews, reproduced from Self and Rampino (2012, figure 2b).

Activity between 1964 and 2017. Almost no activity was reported from Agung during 1964-2017. Weak solfataric activity from within the summit crater was reported in 1989 (SEAN 14:07). MODVOLC thermal alerts were reported intermittently on one or two days during a few years (2001, 2002, 2004, 2006, 2008, 2012, 2013), but all of the alerts were located on the middle or lower flanks, suggesting their source was agriculture or forest fires, unrelated to volcanic activity. Chaussard et al. (2013) reported inflation centered on the summit at a rate of 7.8 cm/year between mid-2007 and early 2009, followed by slow deflation at a rate of 1.9 cm/year until mid-2011 (the last acquired data).

Summary of September-December 2017 Activity. Increases in seismic activity were first noted at Agung during mid-August 2017. Exponential increases in the rate of events during the middle of September led PVMBG to incrementally raise the Alert Level from I to IV (lowest to highest) between 14 and 22 September. Steam-and-gas emissions were intermittently observed 50-500 m above the summit crater from the end of September through October, with occasional bursts as high as 1,500 m. Seismicity dropped off almost as quickly as it rose, beginning on 20 October, and then continued a more gradual decrease through the end of the month and into November. The number and intensity of hot spots observed within the summit crater increased during September, then leveled off during October.

Ash emissions first appeared on 21 November, rising to 700 m above the summit. Ash density and heights of plumes increased several times during the rest of November to about 3,000 m. Ashfall as deep as 5 mm affected neighboring communities, and was reported several hundred kilometers from the summit; the international airport about 60 km SW was forced to close for a few days at the end of the month. Thermal data indicated effusion of lava into the summit crater at the end of November. After 30 November, emissions continued, primarily comprised of steam and gas, with intermittent plumes of dense ash, rising up to 2.5 km above the summit throughout December.

Activity during August-September 2017. In their monthly report of volcanic activity for August 2017, PVMBG noted that 49 volcanoes, including Agung, were listed at Alert Level 1, meaning "Normal", with no apparent increases in visual or seismic activity. The first signs of renewed unrest at Agung appeared as an increase in the rate of deep volcanic earthquakes (VA or Vulkanik Dalam) beginning on 10 August 2017. Shallow volcanic earthquakes (VB or Vulkanik Dangkal) began to increase two weeks later on 24 August, followed by an increase in the number of local tectonic earthquakes on 26 August (figure 3). Based on this increased seismicity, and an observation on 13 September of new solfataric activity at the bottom of the summit crater, PVMBG raised the Alert Level the following day from Level I (Normal) to Level II (Beware); the Aviation Color Code was raised to Yellow on a four-color scale (Green, Yellow, Orange, Red). The deeper earthquakes (VA) had a seismic amplitude range from 3-10 mm. The shallow earthquakes (VB) had an amplitude range of 2-7 mm. Otherwise, there was no surface expression of activity during September.

Figure (see Caption) Figure 3. Seismic activity at Agung between 1 July and 13 September 2017. The Y-axis is the number of daily earthquakes. The increase in deep volcanic seismicity (VA, or Vulkanik Dalam) that began on 10 August 2017 was followed two weeks later by an increase in shallow volcanic seismicity (Vulkanik Dangkal or VB). Courtesy of PVMBG (Peningkatan Tingkat Aktivitas Gunung Agung, 14 September 2017).

The Agung Volcano Observatory (AVO) is located in Rendang village about 8 km SW. Webcams are located in Rendang and in Bukit Asah, about 8 km W. On 15 September 2017 a steam emission was observed rising 50 m above the crater rim. The AVO issued a VONA on 18 September noting a rapid increase in volcanic earthquake activity with a small hot spot detected in satellite data. This contributed to them raising the Alert Level again to Level III (Standby), resulting in a 6-km-radius exclusion zone activated around the summit, extending to 7.5 km on the N, SE, and SSW flanks where the pyroclastic flows of 1963 had caused the most damage. Many of the 50,000 village residents within the 6 km exclusion zone began voluntary evacuations. The communities affected included Jungutan (7 km S) and Buana Giri (12 km SE) villages in the Bebandem District, Sebudi Village (6 km SW) in the Selat Subdistrict, Besakih Village (12 km SW) in the Rendang Subdistrict, and Dukuh (4 km NE) and Ban (7.5 km NW) villages in the Kubu Subdistrict. About 9,500 people had voluntarily evacuated from the villages by 22 September 2017.

The observatory issued another VONA on 19 September 2017, reporting an 'ash cloud' at 0255 UTC (1055 Central Indonesia Time, or WITA). It was described as a dense, white plume moving to the W. Around the same time (0240 UTC) MODVOLC recorded ten thermal alerts on the N and E flanks. Bali's Regional Disaster Management Agency (BPBD) reported in Antara News on 19 September that the source of the smoke and ash were forest fires caused by excessively dry conditions.

A VONA issued by AVO in the morning of 22 September stated that a steam emission about 50 m above the summit drifted NW. During the evening of 22 September, PVMBG raised the Alert Level to Level IV (Caution), the highest of the four-level scale, based primarily on continuing increases in seismicity. They expanded the exclusion zone to 9 km around the summit, and to 12 km in the areas S, SE, and NNE. The number of evacuees had risen to nearly 35,000 people by 24 September. Steam-and-gas plumes were intermittently observed rising to 200 m above the crater rim during the rest of September. By 26 September, PVMBG reported increasing seismic activity with 579 deep volcanic (VA) quakes, 373 shallow quakes (VB), and 50 local tectonic events that day. Seismicity continued to escalate through the end of the month. By the end of September, the government was assisting with the logistics of evacuating tens of thousands of livestock, primarily cattle, as well as over 90,000 people from within and around the 9 km exclusion zone. MAGMA Indonesia reported that new steaming and thermal areas within the summit crater expanded during the last week of the month.

Activity during October 2017. Narrow steam plumes rose 50-200 m above the summit crater during the first half of October. The rate of earthquakes during the last week of September and the first week of October continued to fluctuate at high levels, averaging 1-3 per minute, and more than 600 per day. By the first week of October, shallow earthquakes alone had increased to more than 200 per day, suggesting the possibility of magmatic activity at shallow depth. Satellite data showed increasing steam emissions along the NE edge of the crater rim. Tiltmeter data showed sudden deflation on 1 October, followed by continued inflation through 5 October. AVO released a VONA on 7 October noting a steam plume rising 1,500 m above the summit crater at 1245 UTC and drifting E (figure 4).

Figure (see Caption) Figure 4. A steam plume rose 1,500 m above the summit of Agung on 7 October 2017. Courtesy of PVMBG (Penurunan Status Gunungapi Agung, Bali Dari Level IV (awas) Ke Level III (siaga) Tanggal 29 Oktober 2017 Pukul 16.00 WITA).

During the second half of the month, steam plumes were denser and rose more frequently to 200-500 m above the summit crater. BNPB flew drones over the summit on 20 and 29 October 2017 and captured 400 aerial photographs (figures 5 and 6). The images revealed a widening of the fracture zone on the E side of the summit crater, and a new fracture on the SE side.

Figure (see Caption) Figure 5. A view into the summit crater of Agung on 20 October 2017, taken by a BNPB drone. Steam fumaroles rose from the NNE flank. N is to the left. Courtesy of PVMBG (Penurunan Status Gunungapi Agung, Bali Dari Level IV (awas) Ke Level III (siaga) Tanggal 29 Oktober 2017 Pukul 16.00 WITA).
Figure (see Caption) Figure 6. A view into the summit crater of Agung on 29 October 2017, taken by a BNPB drone. The steam plumes rose from the NE corner of the summit crater. The NE rim of the crater slopes away to the upper left. Courtesy of PVMBG (Penurunan Status Gunungapi Agung, Bali Dari Level IV (awas) Ke Level III (siaga) Tanggal 29 Oktober 2017 Pukul 16.00 WITA).

PVMBG noted a decline in seismicity beginning on 20 October 2017 which continued through the end of the month (figure 7), leading them to lower the Alert Level from IV to III on 29 October, and reduce the exclusion zone to a 6 km radius, plus a 7.5 km area in the NNE, SE and SSW sectors. In their late October report, they observed that remote sensing thermal infrared data had detected an increase in the thermal energy beginning on 10 July 2017, in the form of an increased number of hot spots within the summit crater. During August and September, the number of hot spots had increased significantly and correlated with the increases in seismicity (figure 8). The intensity of the thermal anomalies then decreased during October. Inflation resumed in mid-August and peaked in mid-September. After that, the GPS data indicated deflation at lower levels, but uplift of 6 cm occurred near the summit. The deformation rate slowed after 20 October.

Figure (see Caption) Figure 7. Daily seismic activity at Agung from 27 July-29 October 2017. Seismicity decreased noticeably on 20 October 2017, leading PVMBG to lower the Alert Level from IV to III on 29 October. Note that the vertical axis counting the number of daily seismic events ranges from 0 to 1,200, while in figure 3 the same axis ranges from 0 to 14. Courtesy of MAGMA Indonesia (Penurunan Status Gunungapi Agung, Bali dari Level IV (AWAS) ke Level III (SIAGA) Tanggal 29 Oktober 2017 pukul 16.00 WITA).
Figure (see Caption) Figure 8. Satellite thermal imagery from Citra-Sentinel 2 revealed an increase in the number and intensity of hotspots within the summit caldera of Agung during September 2017, followed by a decrease in early October. Courtesy of PVMBG (Penurunan Status Gunungapi Agung, Bali Dari Level IV (awas) Ke Level III (siaga) Tanggal 29 Oktober 2017 Pukul 16.00 WITA).

Activity during November 2017. For the first three weeks of November, dense white steam plumes rose 50-500 m above the summit crater. A VONA issued late on 11 November reported a 500-m-high steam plume. Seismicity continued at a much lower rate than during late September-October, with tens of daily events as opposed to hundreds.

The first ash emission of the current eruption occurred on 21 November at 1705 local time; the plume rose to 700 m and drifted ESE (figure 9). Trace amounts of ashfall were reported in the Pidpid-Nawehkerti area about 9 km SE. At the time of the first ash emission, BNPB reported the number of evacuees living in temporary housing at about 25,000. The emission was preceded by a low-frequency tremor. Multiple volcanic ash advisories were issued by the Darwin VAAC on 21 November, although the ash was not visible in satellite imagery due to weather clouds. Continuous tremor with 2-5 mm amplitude was recorded the following three days, and ash-and-steam emissions rose 300-800 m above the summit crater.

Figure (see Caption) Figure 9. The first reported ash emission from Agung in 53 years rose 700 m and drifted SE on 21 November 2017. Courtesy of PVMBG (Letusan Gunung Agung Selasa, 21 November 2017 Pukul 17.05 WITA).

A larger emission on 25 November sent black-gray ash plumes 2,000 m above the crater rim (figure 10) which then drifted W. The Darwin VAAC reported an ash plume visible in satellite imagery at 7.6 km altitude drifting WSW. Emissions continued later in the day, rising 4.6-6.7 km altitude and extending SE. Bright incandescence at the summit crater was observed that night. Ashfall was reported to the WSW in the villages of Menanga and Rendang (12 km SW) at the AVO Post, and also in Besakih Village, located in the upper part of Pempatan (8 km W). A number of international flights were cancelled from the I Gusti Ngurah Rai International Airport in Denpasar (60 km SW), affecting about 2,000 passengers, although the airport remained open.

Figure (see Caption) Figure 10. An ash emission rose at least 1,500 m above the summit of Agung on 25 November 2017 and drifted W. Courtesy of PVMBG (Letusan Gunung Agung 25 November 2017 Pukul 17:30 Wita).

Around 0545 local time the following day (26 November), the intensity of the ash emissions increased; the top of the plume reached 3,300 m above the summit at 1100 local time, and was drifting SE and E (figure 11). Ashfall was reported in many areas downwind including North Duda (9 km S), Duda Timur (12 km S), Pempetan, Besakih, Sideman (15 km SSW), Tirta Abang, Sebudi (6 km SW), Amerta Bhuana (10 km SSW), and some villages in Gianyar (20 km WSW) (figure 12). The largest amount, deposits 5 mm thick, was reported in Sibetan (11 km SSE). Trace amounts of ash were also reported much farther away, in Nusa Penida (an island 40 km S), Lombok (100 km ESE), and Sumbawa, 250 km E on the island of West Nusa Tenggara. Explosions from the crater were audible 12.5 km away that evening. Incandescence at the summit was observed from Bukit Asah and Batulompeh. The Darwin VAAC reported continuous ash emissions to 7.9 km altitude drifting SE throughout most the day, increasing to 9.1 km later in the day; ashfall was also reported at the international airport.

Figure (see Caption) Figure 11. A dense plume of ash rose 3,000 m above the summit of Agung and drifted ESE on 26 November 2017. Courtesy of PVMBG (Peningkatan Status Gunungapi Agung, Bali Dari Level III (siaga) Ke Level IV (awas), 27 November 2017).
Figure (see Caption) Figure 12. Ash from an eruption of Agung on 26 November 2017 covered garden plants in Jungutan Village, 7 km SE. Courtesy of Reuters.

The airport in Denpasar was forced to close during 27-29 November 2017. On those days ash drifted in multiple directions at different altitudes; it was observed drifting E at 9.1 km altitude, SW at 7.6 km altitude, and was moving S below 6.1 km. This increase in emissions led PVMBG to raise the Alert Level from III to IV on 27 November. Pictures and video showed a white steam plume adjacent to a gray ash plume rising from the crater, suggesting two distinct sources (figure 13).

Figure (see Caption) Figure 13. A white steam plume and dense gray ash both rose from the summit of Agung on 27 November 2017. Photo by K. Parwata, courtesy of Sutopo Purwo Nugroho, Twitter.

A single MODVOLC thermal alert appeared at the summit that day, along with a strong thermal anomaly in the MIROVA system data (figure 14) consistent with the appearance of new lava in the summit crater. The tiltmeter installed at the Yehkori station 4 km S of the summit showed continued inflation of up to 6 microradians between 22 and 27 November (figure 15). PVMBG also increased the exclusion zone to a radius of 8 km from the summit crater plus areas 10 km from the summit to the NNE, SE, S, and SW.

Figure (see Caption) Figure 14. A MIROVA plot of satellite infrared data for the year ending 23 February 2018 showed the first thermal anomaly from Agung in late November 2017, consistent with the emergence of lava in the summit crater. Courtesy of MIROVA.
Figure (see Caption) Figure 15. A steady inflation was measured by the tiltmeter located at the Yehkori station 4 km S of the summit of Agung between 22 November and 27 November. Courtesy of PVMBG (Peningkatan Status Gunungapi Agung, Bali Dari Level III (siaga) Ke Level IV (awas), 27 November 2017).

MAGMA Indonesia reported that beginning with the ash eruption on 21 November, lahars appeared in the Tukad Yehsa, Tukad Sabuh, and Tukad Beliaung drainages on the S flank, as well as Tukad Bara on the N flank. As of the end of November 2017, these lahars had impacted houses, roads, and agricultural areas. Although ash emissions increased, and lava was confirmed within the summit crater during the last week of November, the number of seismic events remained well below the values recorded during September and October (figure 16).

Figure (see Caption) Figure 16. Seismicity at Agung decreased significantly beginning on 20 October 2017 and remained well below 200 daily events throughout November, even though ash emissions began on 21 November. Courtesy of PVMBG (Peningkatan Status Gunungapi Agung, Bali Dari Level III (siaga) Ke Level IV (awas), 27 November 2017).

Ash emissions were reported by PVMBG rising to 3,000 m above the summit and drifting S on 27 November (figure 17). Continuing ash emission during 28-29 November rose to 2,000-4,000 m above the summit and drifted WSW (figure 18). Continuous seismic tremors were recorded during 28 November-1 December.

Figure (see Caption) Figure 17. Ash plumes from Agung rose to altitudes of around 6,000 m (3,000 m above the summit crater) and drifted S on 27 November 2017. Image courtesy of MAGMA Indonesia (Peningkatan Status Gunungapi Agung, Bali Dari Level Ill (SIAGA) ke Level IV (AWAS), 27 November 2017 10:07 WIB, Ir. Kasbani, M.Sc.).
Figure (see Caption) Figure 18. A dense plume of steam and ash rose from Agung and drifted away from this villager and his livestock on 28 November 2017. Courtesy of CNN.

With the increase in ash emissions during the last days of November 2017, satellite instruments also recorded significant releases of SO2 (figure 19). MAGMA Indonesia reported on 1 December that satellite data also recorded high temperatures consistent with new lava within the crater on 27, 28, and 29 November 2017. They estimated the volume of lava in the crater to be about 20 million cubic meters, equivalent to about a third of the total crater volume. The base of the ash-and-steam plumes was often reddish during 29 November-5 December reflecting incandescence from the lava in the crater (figure 20).

Figure (see Caption) Figure 19. The concentrations of SO2 emitting from Agung increased to levels that were easily detected by the Ozone Mapper Profiler Suite (OMPS) on the Suomi National Polar-orbiting Partnership (Suomi-NPP) satellite on 27 (top) and 28 (bottom) November 2017. The concentration of SO2 is measured in Dobson Units, a measure of the molecular density of the SO2 in the atmosphere. These NASA Earth Observatory images were created by Joshua Stevens, using OMPS data from the Goddard Earth Sciences Data and Information Services Center (GES DISC).
Figure (see Caption) Figure 20. Incandescence appeared at the base of the ash-and-steam plume at Agung on 29 November 2017, consistent with lava effusion in the summit crater. Courtesy of MAGMA Indonesia (Perkembangan Terkini Aktivitas Gunung Agung (1 Desember 2017 21:00 WITA), 2 December 2017 07:55 WIB, Ir. Kasbani, M.Sc.).

By 29 November, continuous ash emissions were rising to 6.4 km altitude and drifting from the SW towards the S, becoming diffuse over the Denpasar region (figure 21). The plume was observed moving E at the same elevation on 30 November, lowering to 5.5 km later in the day. Although emissions were primarily steam and gas beginning on 30 November, pilot reports on 1 December indicated ash was still visible SE of Agung, and steam-and-ash emissions were continuing. Steam-only emissions were reported on 2 December rising less than 1,000 m above the summit.

Figure (see Caption) Figure 21. Gas-and-ash emissions from Agung on 29 November 2017 were drifting both W and S in this false-color image generated by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite. The image uses a combination of shortwave infrared light and natural color, making it easier to differentiate between ash, clouds, and forest. The plumes appear to rise from two vents in the volcano's summit crater. Courtesy of NASA Earth Observatory.

Activity during December 2017. Steam, gas, and ash emissions continued throughout December 2017. During the first two weeks, emissions were primarily steam and gas, rising up to 2,000 m (figure 22), and incandescence was often observed at the summit. Dense gray ash emissions were observed, however, during 1-2 December. BNPB noted on 5 December that 63,885 evacuees were distributed in 225 evacuation shelters. On 8 December at 0759 a brief event generated a dense ash plume that rose 2.1 km above the crater rim and drifted W (figure 23). Minor amounts of ash were deposited on the flanks, and lapilli were reported in Temakung. A second ash plume rose 3 km at 1457 later that day.

Figure (see Caption) Figure 22. A burst of dense steam rose as high as 1,500 m from the crater of Agung on 5 December 2017 at 0848 local time (WITA) and drifted E, after which only a narrow diffuse plume remained. View is from the S. Courtesy of Sutopo Purwo Nugroho, Twitter.
Figure (see Caption) Figure 23. An eruption at Agung on 8 December 2017 at 0759 WITA sent a dense gray ash plume 2,100 m above peak to the W. View is from the S. Courtesy of Sutopo Purwo Nugroho, Twitter.

The Darwin VAAC reported multiple daily explosions during 8-15 December, creating ash plumes that drifted NW, W, and WSW at altitudes between 4.3 and 5.5 km. The explosions were visible in the webcams and from ground-based observers, and occasionally in satellite imagery when not blocked by weather clouds. VONA's were issued for events on 8 and 12 December. Multiple events during 11-12 December sent plumes rising up to 2.5 km above the crater rim and drifting NW and W (figure 24).

Figure (see Caption) Figure 24. A small ash emission rose from the crater of Agung during the early morning of 11 December 2017. Courtesy of Sutopo Purwo Nugroho, Twitter.

The Darwin VAAC reported larger ash emissions to 7.6 km altitude on 15 and 16 December interspersed with lower altitude (5.5-6.1 km) plumes. Continuing, regular discrete emissions during 16-17 December rose to 6.1 km and drifted WNW. An overhead image of the summit crater of 16 December revealed that, since a similar photo was taken on 20 October, new lava had filled about 1/3 of the crater with an estimated 30 million cubic meters of material (figure 25).

Figure (see Caption) Figure 25. Repeated overhead images of the Agung summit crater taken on 20 October and 16 December 2017 showed new lava filling about 1/3 of the crater with an estimated 30 million cubic meters of material. Posted on Twitter by Sutopo Purwo Nugroho for BNBP.

Discrete emissions to 5.5 km moving N and NNE were common during 18-21 December. Ash and steam drifted both E and W from the summit on 22 December. An ash emission on 23 December rose to 5.8 km and drifted NE, after which repeated emissions continued, rising to 4.6 km (figure 26). Ash fell on the flanks and in Tulamben, Kubu (9 km NE). In the morning of 24 December, a much larger plume drifting W at 10.7 km altitude was visible in satellite imagery. It dissipated after a few hours, and a separate plume was observed drifting NE at 5.5-5.8 km (figure 27); emissions continued throughout the day and into the next. PVMBG reported that the ash deposits from the NE-drifting plume were up to 3 mm thick (figure 28).

Figure (see Caption) Figure 26. An event at Agung on 23 December 2017 sent a dense, gray plume to 2,500 m above the crater rim at 1157 WITA. View is from a village on the W flank, likely about 7 km from the summit. Courtesy of Sutopo Purwo Nugroho, Twitter.
Figure (see Caption) Figure 27. Agung erupted steam and ash with a plume height of 2,000-2,500 m on 24 December 2017 at 1005 WITA. Courtesy of Sutopo Purwo Nugroho, Twitter.
Figure (see Caption) Figure 28. Map showing distribution and thickness of volcanic ash and lapilli from the ash emissions at Agung that began on 24 December 2017 at 1005 WITA. A thin layer of ash was deposited in a narrow NE trending band on the NE side of Agung. Courtesy of Sutopo Purwo Nugroho, Twitter.

As of 25 December, BNPB reported just over 70,000 evacuees spread out in 239 shelters. Discrete ash emissions continued through the end of the month rising as high as 2 km above the crater rim and drifting in several different directions. The last VAAC report of 2017 indicated an ash plume drifting W at 4.3 km altitude on 31 December.

References: Chaussard E, Amelung F, Aoki Y, 2013, Characterization of open and closed volcanic systems in Indonesia and Mexico using InSAR time series. J Geophys Res Solid Earth, 118:3957–3969. DOI: 10.1002/jgrb.50288.

Fontijn K, Costa F, Sutawidjaja I, Newhall C G, Herrin J S, 2015, A 5000-year record of multiple highly explosive mafic eruptions from Gunung Agung (Bali, Indonesia): implications for eruption frequency and volcanic hazards. Bull Volcanol, 77: 59. DOI: 10.1007/s00445-015-0943-x.

Self S, Rampino M, 2012, The 1963–1964 eruption of Agung volcano (Bali, Indonesia). Bull Volcanol 74:1521–1536. DOI: 10.1007/s00445-012-0615-z.

Information Contacts: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); Badan Nasional Penanggulangan Bencana (BNPB), National Disaster Management Agency, Graha BNPB - Jl. Scout Kav.38, East Jakarta 13120, Indonesia (URL: http://www.bnpb.go.id/); MAGMA Indonesia, Kementerian Energi dan Sumber Daya Mineral (URL: https://magma.vsi.esdm.go.id/); NASA Earth Observatory, EOS Project Science Office, NASA Goddard Space Flight Center, Goddard, Maryland, USA (URL: http://earthobservatory.nasa.gov/); NASA Goddard Space Flight Center (NASA/GSFC), Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Antara News (URL: https://bali.antaranews.com); Sutopo Purwo Nugroho, Twitter (URL: https://twitter.com/sutopo_pn); Cable News Network (CNN), Turner Broadcasting System, Inc. (URL: http://www.cnn.com/); Reuters (URL: http://www.reuters.com/).

Weekly Reports - Index


2018: January | February | March | April | May | June
2017: September | October | November | December


13 June-19 June 2018 Citation IconCite this Report


PVMBG reported that at 1105 on 13 June an event at Agung produced a dense ash plume that rose around 2 km above the crater rim and drifted SW and W. Based on analysis of the seismic data, the event lasted two minutes and 12 seconds. Another event was detected at 2115 on 15 June, though foggy conditions prevented estimations of the ash plume height; ash fell in areas W, including in Puregai (7 km W). The Alert Level remained at 3 (on a scale of 1-4) and the 4-km-radius exclusion zone was unchanged.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


6 June-12 June 2018 Citation IconCite this Report


PVMBG reported that during 1 May-7 June activity at Agung remained at a relatively high level. Emissions were mostly water vapor, occasionally with ash. In general, tiltmeter and GPS showed long-term deflation since December 2017, though inflation began to be detected the second week of May; deformation analysis indicated that magma continued to accumulate about 3-4 km below the crater. Low- and high-frequency earthquakes also suggested rising magma. Sulfur dioxide flux was 190-203 tons/day, and thermal anomalies in the crater were identified in satellite data. The erupted volume of lava was estimated to be 23 million cubic meters, equivalent to about a third of the total crater volume. At 2214 on 10 June an event generated an ash plume that drifted W at an unspecified altitude. The Alert Level remained at 3 (on a scale of 1-4) and the exclusion zone was stable at a 4-km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


23 May-29 May 2018 Citation IconCite this Report


PVMBG reported that although there were some periods of foggy conditions during 23-29 May, white plumes were occasionally observed rising as high as 400 m above Agung’s crater rim. At 0539 on 29 May an event generated an ash plume that rose 500 m above the crater rim and drifted SW. The Alert Level remained at 3 (on a scale of 1-4) and the exclusion zone continued at a 4-km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


16 May-22 May 2018 Citation IconCite this Report


PVMBG reported that at 1719 on 19 May an event at Agung generated an ash plume that rose 1 km above the crater rim and drifted SE. The Alert Level remained at 3 (on a scale of 1-4) and the exclusion zone continued at a 4-km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


25 April-1 May 2018 Citation IconCite this Report


PVMBG reported that at 2245 on 30 April an event at Agung generated an ash plume that rose 1.5 km above the crater rim and drifted SW. Seismicity was dominated by low-frequency earthquakes related to gas-and-steam emissions. The Alert Level remained at 3 (on a scale of 1-4) and the exclusion zone continued at a 4-km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


18 April-24 April 2018 Citation IconCite this Report


PVMBG reported that although there were often foggy conditions during 18-24 April, white plumes were observed rising as high as 300 m above Agung’s crater rim and drifting E. The Alert Level remained at 3 (on a scale of 1-4) and the exclusion zone continued at a 4-km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


11 April-17 April 2018 Citation IconCite this Report


Based on webcam views, satellite data, and ground-based observations, the Darwin VAAC reported that on 11 April an event at Agung generated an ash plume that rose to an altitude of 3.7 km (12,000 ft) a.s.l. and drifted SW.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Darwin Volcanic Ash Advisory Centre (VAAC)


4 April-10 April 2018 Citation IconCite this Report


PVMBG reported that an event at Agung at 1737 on 5 April generated an ash plume that rose 500 m above the crater rim and drifted W. Seismicity was dominated by high- and low-frequency earthquakes. The Alert Level remained at 3 (on a scale of 1-4) and the exclusion zone continued at a 4-km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


21 March-27 March 2018 Citation IconCite this Report


In a VONA, PVMBG reported that at 1009 on 26 March an event at Agung generated an ash plume that rose at least to an altitude of 3.6 km (11,650 ft) a.s.l. and drifted NW. The Alert Level remained at 3 (on a scale of 1-4) and the exclusion zone continued at a 4-km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


7 March-13 March 2018 Citation IconCite this Report


PVMBG reported that although there were sometimes foggy conditions during 7-13 March, white plumes were observed rising as high as 600 m above Agung’s crater rim and drifting E. An event at 2332 on 11 March generated an ash plume that rose about 950 m and drifted E. The Alert Level remained at 3 (on a scale of 1-4) and the exclusion zone continued at a 4-km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


28 February-6 March 2018 Citation IconCite this Report


PVMBG reported that on 28 February gray-white plumes rose as high as 300 m above Agung’s crater rim. During 1-5 March white plumes rose as high as 500 m above the crater rim. The Alert Level remained at 3 (on a scale of 1-4) and the exclusion zone continued at a 4-km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


14 February-20 February 2018 Citation IconCite this Report


PVMBG reported that an event at Agung recorded at 1149 on 13 February generated an ash plume that rose to an altitude of 4.5 km (14,900 ft) a.s.l. and drifted E. The Alert Level remained at 3 (on a scale of 1-4) and the exclusion zone continued at a 4-km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


7 February-13 February 2018 Citation IconCite this Report


On 10 February PVMBG reported that activity at Agung had declined during the previous month or two leading the observatory to lower the Alert Level to 3 (on a scale of 1-4) and adjusted the exclusion zone to a 4-km radius. The report noted that the tallest eruption plume in January was 2.5 km above the crater rim, occurring on 19 January, and the last event on 24 January generated a plume that rose 1 km. The volume of erupted lava was an estimated 20 million cubic meters in December 2017, and had not significantly changed. Seismicity continued to fluctuate, though the number and magnitude of events had declined. Satellite data showed a decrease in thermal output reflective of a reduced lava flow rate. PVMBG warned that activity at Agung is still high and unstable; tiltmeter data showed low rates of inflation (GPS patterns were stable) and gas-emission data indicated magma movement at depth, though at a lower intensity compared to values measured at the end of November 2017. An event at 1149 on 13 February generated as ash plume that rose 1.5 km above the crater rim.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


24 January-30 January 2018 Citation IconCite this Report


PVMBG reported that white-and-gray plumes rose as high as 1 km above Agung’s crater rim during 24-25 January. Foggy conditions prevented visual observations of the crater during 26-30 January. The Alert Level remained at 4 (on a scale of 1-4) and the exclusion zone continued at a 6-km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


17 January-23 January 2018 Citation IconCite this Report


PVMBG reported that the eruption at Agung continued during 17-23 January, with gas-and-steam plumes rising from the crater punctuated by occasional ash emissions. An event at 2126 on 17 January generated a plume that rose 1.5 km above the crater rim and drifted E. An event was recorded at 1944 on 18 January, though fog prevented confirmation of a plume. At 1920 on 19 January a Strombolian event produced an ash plume that rose as high as 2.5 km and drifted E, and ejected incandescent material as far as 1 km from the crater. Incandescence emanated from the crater for about two hours after the event. White-to-gray plumes rose 500 m during 22-23 January. The Alert Level remained at 4 (on a scale of 1-4) and the exclusion zone continued at a 6-km radius.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


10 January-16 January 2018 Citation IconCite this Report


PVMBG reported that during 10-16 January gray-and-white plumes generally rose as high as 500 m above Agung’s crater rim and drifted S, SE, and E. An event at 1754 on 11 January produced an ash plume that rose 2.5 km above the crater rim and drifted NE (likely causing ashfall in areas downwind), and another event at 0723 on 15 January generated an ash plume that rose 2 km. As of 11 January BNPB estimated that 53,207 evacuees were spread out in 233 shelters. The Alert Level remained at 4 (on a scale of 1-4) and the exclusion zone continued at a 6-km radius.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


3 January-9 January 2018 Citation IconCite this Report


BNPB reported that activity at Agung continued to fluctuate at a high level. Visual observations as well as seismic, deformation, and geochemistry data indicated that the eruption was continuing, though deformation data in recent days showed a stagnant trend. As of the morning of 4 January BNPB noted that there were 70,610 evacuees spread out in 240 shelters. The exclusion zone was adjusted to 6 km in all directions that same day, allowing thousands of displaced people the option to return to their homes. An estimated 17,115 people in seven villages have residences within the 6-km-radius exclusion zone.

PVMBG reported that during 3-9 January gray-and-white plumes rose as high as 2 km above the crater rim and drifted in multiple directions. The Alert Level remained at 4 (on a scale of 1-4).

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


27 December-2 January 2018 Citation IconCite this Report


PVMBG reported that during 27 December 2017-2 January 2018 gray-and-white plumes rose as high as 2 km above Agung’s crater rim and drifted W, SW, and E. Incandescence from the crater was often observed at night. Ash fell in several local villages including Badeg, Yeha, Temukus, Besakih (11 km WSW), and Muncan (12 km SW) on 1 January, and Rendang post on 2 January. The Alert Level remained at 4 (on a scale of 1-4), and the exclusion zones continued at a general 8-km radius and 10 km in the NNE, SE, S, and SW directions.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


20 December-26 December 2017 Citation IconCite this Report


PVMBG reported that during 20-26 December gray-and-white plumes rose as high as 2 km above Agung’s crater rim and drifted W and E; weather clouds and fog sometimes prevented visual observations. Incandescence from the crater was sometimes observed at night. BNPB reported that during 22-23 December events generated dense gray ash plumes that rose as high as 2.5 km above the crater rim and drifted NE. Ash fell on the flanks and in Tulamben, Kubu. As of 25 December there were 71,045 evacuees spread out in 239 shelters. The Alert Level remained at 4 (on a scale of 1-4), and the exclusion zones continued at a general 8-km radius and 10 km in the NNE, SE, S, and SW directions.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


13 December-19 December 2017 Citation IconCite this Report


PVMBG reported that during 13-19 December gray-and-white plumes rose as high as 2.5 km above Agung’s crater rim and drifted W, N, and E; weather clouds and fog sometimes prevented visual observations. Incandescence from the crater was sometimes observed at night. The Alert Level remained at 4 (on a scale of 1-4), and the exclusion zones continued at a general 8-km radius and 10 km in the NNE, SE, S, and SW directions.

BNPB posted two map-view images of Agung, one from 20 October showing pre-eruptive conditions and one from 16 December showing the lava that had erupted onto the crater floor, noting that about 1/3 of the crater had been filled with an estimated 20 million cubic meters of lava.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


6 December-12 December 2017 Citation IconCite this Report


Based on BNPB and PVMBG reports, the eruption at Agung continued during 6-12 December, with high seismicity and nighttime crater incandescence often visible. On 8 December at 0759 an event generated a dense ash plume that rose 2.1 km above the crater rim and drifted W. Minor amounts of ash were deposited on the flanks, and lapilli was reported in Temakung. An ash plume rose 3 km at 1457. The number of evacuees on 10 December was 70,079 (spread out in 237 shelters). Ash plumes rose as high as 2 km. Lahars were observed in a drainage originating on the flanks of Agung. An explosion at 0549 on 11 December generated a dense ash plume that rose 2.5 km and drifted W and NW. Multiple ash-plume events were observed during 11-12 December, with plumes rising 1.5 km above the crater rim. The Alert Level remained at 4 (on a scale of 1-4), and the exclusion zones continued at a general 8-km radius and 10 km in the NNE, SE, S, and SW directions.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


29 November-5 December 2017 Citation IconCite this Report


PVMBG reported that the eruption at Agung, which began on 21 November, continued during 30 November-5 December. On 29 November gray ash plumes levels were rising to 2 km above the crater rim, resulting in ashfall to the SE. During 30 November-5 December emissions continued to rise 2 km; most were white in color, but dense gray ash emissions were noted during 1-2 December. Satellite data indicated that lava effusion continued at least through 1 December, and the erupted volume of lava was estimated to be 20 million cubic meters, equivalent to about a third of the total crater volume. The base of the plume was often reddish during 29 November-5 December reflecting incandescence from lava in the crater. BNPB noted on 5 December that 63,885 evacuees were distributed in 225 evacuation shelters.

Lahars were first noted on 21 November and continued to be observed through 5 December. The lahars flowed down drainages on the S flank (along the Tukad Yehsa, Tukad Sabuh, and Tukad Beliaung drainages) and also down the Tukad Bara drainage on the N flank, impacting houses, roads, and agricultural areas. The Alert Level remained at 4 (on a scale of 1-4), and the exclusion zones continued at a general 8-km radius and 10 km in the NNE, SE, S, and SW directions.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


22 November-28 November 2017 Citation IconCite this Report


PVMBG reported that at 1730 on 25 November, after the number of volcanic earthquakes significantly increased, ash plumes rose 1.5 km above Agung’s crater rim and drifted 12 km WSW. Ashfall was reported in areas SW including Besakih (7 km SW), hamlets in the upper part of Pempatan (7.5 km W), and Temukus, prompting remaining residents to evacuate to the S. Eight inbound and 13 outbound international flights were cancelled, affecting 2,087 passengers. Crater incandescence was observed at 2100, signifying the presence of lava in the crater. BNPB noted that the number of evacuees was 25,016 (spread out in 224 shelters)

On 26 November dark gray ash plumes rose 2 km at 0505, 3 km at 0545, and 4 km at 0620, and drifted E and SE. Ash emissions continued throughout the day; a few explosions were heard within a 12-km radius. PVMBG issued a Volcano Observatory Notice for Aviation (VONA) elevating the Aviation Color Code from Orange to Red. Satellite data recorded sulfur dioxide gas concentrations ranging from 1,000 to 2,000 tons/day. Ashfall was reported in several areas downwind including North Duda (9 km S), Duda Timur (12 km S), Pempetan, Besakih, Sideman (15 km SSW), Tirta Abang, Sebudi (6 km SW), Amerta Bhuana (10 km SSW) in Klungkung, and some villages in Gianyar (20 km WSW). Ashfall was the thickest (5 mm) in Sibetan (11.5 km S). News sources noted that Lombok International Airport closed during 26-27 November.

PVMBG raised the Alert Level to 4 (the highest level on a scale of 1-4) on 27 November, and the exclusion zones were expanded to a general 8-km radius and to 10 km in the NNE, SE, S, and SW directions. Dense ash plumes continued to rise 2-4 km above the crater rim. Based on satellite data, the Darwin VAAC reported that ash plumes rose as high as 9.1 km (30,000 ft) a.s.l., or just over 6 km above the crater rim. Pictures and video showed a white steam plume adjacent to a gray ash plume rising form the crater, signifying two distinct active vents. According to news articles the Ngurah Rai International Airport in Bali closed due to the airborne ash. On 28 November BNPB noted that the number of evacuees had increased to 38,678, and were distributed in 225 evacuation centers. The Ngurah Rai International Airport reopened on 29 November, after the Aviation Color Code was lowered to Orange.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); CNN; Darwin Volcanic Ash Advisory Centre (VAAC); Badan Nacional Penanggulangan Bencana (BNPB); The Sun


15 November-21 November 2017 Citation IconCite this Report


PVMBG reported that a phreatic eruption at Agung began at 1705 on 21 November, following a low-frequency tremor signal. An ash plume rose 700 m above the crater rim and drifted ESE. The Alert Level remained at 3 (on a scale of 1-4), and the exclusion zones remained intact (at 6 km, and an additional expansion to 7.5 km in the NNE, SE, S, and SW directions).

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


8 November-14 November 2017 Citation IconCite this Report


PVMBG reported that white plumes from Agung rose as high as 500 m above the crater rim during 8-14 November. The Alert Level remained at 3 (on a scale of 1-4), and the exclusion zones remained intact (at 6 km, and an additional expansion to 7.5 km in the NNE, SE, S, and SW directions).

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


1 November-7 November 2017 Citation IconCite this Report


PVMBG reported that white plumes from Agung rose as high as 500 m above the crater rim during 1-7 November. The Alert Level remained at 3 (on a scale of 1-4), and the exclusion zones remained at 6 km, with an additional expansion to 7.5 km in the NNE, SE, S, and SW directions.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


25 October-31 October 2017 Citation IconCite this Report


On 29 October PVMBG lowered the Alert level for Agung to 3 (on a scale of 1-4), noting a decline in activity, especially since 20 October. The thermal anomaly in the crater identified in satellite data was less intense in October than in September. Beginning on 20 October GPS data showed a slower deformation rate. Seismic signals decreased in number and amplitude, though low-frequency events continued to indicate magma movement. White fumarolic plumes rose as high as 500 m above the crater rim during 20-29 October; a comparison of video taken by drones on 20 and 29 October showed a relative decrease in the intensity of fumarolic emissions. BNPB stated that, despite the decreased Alert Level, the exclusion zones remained intact (at 6 km, and an additional expansion to 7.5 km in the NNE, SE, S, and SW directions). The number of evacuees was 133,457 (spread out in 385 shelters).

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


18 October-24 October 2017 Citation IconCite this Report


PVMBG reported that although foggy conditions at Agung occasionally prevented visual observations, during 18-24 October dense white plumes were seen rising as high as 500 m above the crater rim. Seismicity fluctuated but remained high, though BNPB reported that overall seismicity had decreased. According to BNPB a team launched a drone on 19 October and were able to capture video of the fumarolic emissions from several vents and cracks in the crater. The Alert Level remained at 4 (the highest level on a scale of 1-4) with the exclusion zone at 9 km, and an additional expansion to 12 km in the SE, S, and SW directions.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


11 October-17 October 2017 Citation IconCite this Report


PVMBG reported that although foggy conditions at Agung sometimes prevented visual observations, during 11-17 October dense white plumes were seen rising 200 m above the crater rim. On 14 October BNPB stated that seismicity remained high; PVMBG noted that seismicity was dominated by shallow volcanic events, and the number of volcanic earthquakes remained steady. The governor of Bali extended the state of emergency to 26 October, noting that the Alert Level remained at 4 (the highest level on a scale of 1-4). The number of evacuees was 139,199 (spread out in 389 shelters).

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


4 October-10 October 2017 Citation IconCite this Report


On 5 October PVMBG reported that the rate of volcanic earthquakes at Agung had not increased during the previous 12 days, but continued to fluctuate at a high level. The seismic network detected 1-3 earthquakes per minute on average, with a total more than 600 events per day. The number of shallow volcanic earthquakes increased to 200 per day during 24 September-5 October, possibly indicating that magmatic activity at shallow depths was still high. The number of earthquakes felt by staff at the Mt. Agung Volcano Observatory in Rendang village, 12.5 km SSW, peaked on 27 September and then decreased afterwards. Gas plumes rose 50-200 m above the crater rim. Satellite data indicated an area of water expulsion near the solfatara field on the crater floor thought to reflect a disturbance to the hydrologic system in response to intruded magma at depth. On 5 October BNPB reported that the number of evacuees reached 146,797 (spread out in 427 shelters), though about 28 villages (70,000 people) were located within the evacuation zone. About 10,000 farm animals had also been evacuated. On 7 October a white plume likely composed mostly of water vapor rose 1.5 km above the crater rim and slowly drifted E. During 8-10 October fumarolic plumes rose 50-200 m above the rim. The Alert Level remained at 4 (the highest level on a scale of 1-4) with the exclusion zone at 9 km, and an additional expansion to 12 km in the SE, S, and SW directions.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


27 September-3 October 2017 Citation IconCite this Report


On 29 September PVMBG reported that earthquakes at Agung were becoming stronger with more felt by local residents, and larger ones felt in areas 45-55 km SW including Denpasar and Kuta. Fumarolic emissions were identified in satellite data, as well as hot areas on the crater floor that had enlarged over the previous week. A new fracture on the crater floor emitted steam. After a M 4.2 earthquake was detected at 1627 on 26 September emissions intensified and rose 500 m above the crater rim. On 4 October BNPB reported that seismicity continued to fluctuate at high levels, and weak emissions rose above the crater rim. The number of evacuees reached 141,213 (spread out in 416 shelters) from 78 villages, though about 2,600 in locations outside of the evacuation zone were returning home; there were 28 villages (about 70,000 people) within the evacuation zone. The Alert Level remained at 4 (the highest level on a scale of 1-4) with the exclusion zone at 9 km, and an additional expansion to 12 km in the SE, S, and SW directions.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


20 September-26 September 2017 Citation IconCite this Report


BNPB noted that as of 1300 on 22 September there were 9,421 people displaced from the evacuation zones at Agung. Seismicity continued to increase, therefore later that day on 22 September PVMBG raised the Alert Level to 4 (the highest level on a scale of 1-4) and expanded the exclusion zone to 9 km, with an additional expansion to 12 km in the SE, S, and SW directions. On 24 September BNPB reported that the number of evacuees continued to grow, as residents were leaving the expanded evacuation zones; there were 34,931 people in 238 shelters. The report noted that some people were returning home in the daytime to feed their livestock. On 27 September the number of evacuees reached 96,086 (spread out in 430 shelters), seismic activity continued to escalate, and diffuse white plumes rose 50 m above the crater rim.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB)


13 September-19 September 2017 Citation IconCite this Report


Increased seismicity at Agung, as well as the severity of past eruptions, prompted PVMBG to raise the Alert Level to 2 (on a scale of 1-4). The report noted that volcanic earthquakes (VA) began to be recorded on 10 August and shallow volcanic earthquakes (VB) began to be recorded on 24 August. Local tectonic earthquakes were also recorded and began to increase consistently on 26 August. PVMBG warned the public to stay at least 3 km away from the crater. On 13 September a climber observed a sulfatara plume rising from the bottom of the crater as high as 50 m above the crater rim. During 14-18 September four earthquakes centered around Agung were felt. On 18 September PVMBG reported that the number of VA and VB events continued to increase; the Alert Level was increased to 3. The exclusion zone was increased to 6 km, with an additional expansion to 7.5 km in the N, SE, and SSW directions. Elevations above 950 m were also restricted.

A VEI 5 eruption during 1963-64 produced pyroclastic flows and lahars that caused extensive damage and resulted in more than 1,100 deaths.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


Bulletin Reports - Index


Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

07/1989 (SEAN 14:07) Fumarolic activity

11/1989 (SEAN 14:11) Occasional seismicity but solfatara field quiet

03/2003 (BGVN 28:03) Hot-spots located outside the summit crater are most likely due to fires

01/2018 (BGVN 43:01) New eruption after 54 years; extensive pre-eruption seismicity precedes ash emission on 21 November 2017




Information is preliminary and subject to change. All times are local (unless otherwise noted)


July 1989 (SEAN 14:07) Citation IconCite this Report


Fumarolic activity

Fumarolic and solfataric activity (restricted to the crater) emitted a thin white plume periodically seen from the observatory. In late July, 69 tectonic, three volcanic A-type, and six volcanic B-type events were recorded.

Information Contacts: VSI.


November 1989 (SEAN 14:11) Citation IconCite this Report


Occasional seismicity but solfatara field quiet

Observations from both Rendang (S) and Budakeling (N) Observatories revealed neither white plumes from the solfatara field nor collapses of loose material from the inner crater wall. No explosion sounds from the crater have been heard. An earthquake was felt (MM I) on 9 June; 59 tectonic and two volcanic shocks [were] recorded in November.

Information Contacts: VSI.


March 2003 (BGVN 28:03) Citation IconCite this Report


Hot-spots located outside the summit crater are most likely due to fires

Thermal anomalies were detected by MODIS throughout 2001 and 2002 in zones proximal to the summit of Agung. The first alert occurred on 23 September 2001 when two alert-pixels were detected with a maximum alert ratio of -0.789. Larger anomalies were detected on 12 August 2002 (two alert-pixels with maximum alert ratio of -0.429) and 5 October 2002 (one alert-pixel with alert ratio of -0.536). All the alerts seem to occur outside the summit crater, with the possible exception of 5 October 2002, and are more likely to represent fires than volcanic activity.

No volcanic activity has been reported recently by the Volcanological Survey of Indonesia.

Information Contacts: Diego Coppola and David A. Rothery, Department of Earth Sciences, The Open University, Milton Keynes, MK7 6AA, UK. Thermal alerts courtesy of the HIGP MODIS Thermal Alerts Team (URL: http://modis.higp.hawaii.edu/).


January 2018 (BGVN 43:01) Citation IconCite this Report


New eruption after 54 years; extensive pre-eruption seismicity precedes ash emission on 21 November 2017

A large explosive and effusive eruption lasting about 11 months during 1963-64 at Indonesia's Mount Agung on Bali produced voluminous ashfall, devastating pyroclastic flows that caused extensive damage, and over 1,000 fatalities. The volcano remained largely quiet until renewed seismicity began in August 2017, the prelude to a new eruptive episode, which started in late November 2017 and is ongoing. Self and Rampino (2012) and Fontijn et al. (2015) published detailed summaries of historical activity at Agung prior to this new episode; a brief summary of their work is provided.

Information about the new eruptive episode comes from Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG), also known as the Indonesian Center for Volcanology and Geological Hazard Mitigation (CVGHM), Badan Nasional Penanggulangan Bencana (BNPB) which is the National Board for Disaster Management, the Darwin Volcanic Ash Advisory Center (VAAC), and various sources of satellite data. The first two months of this new episode, through December 2017, are discussed in this report.

Summary of 1963-64 eruption. The February 1963 to January 1964 eruption, Indonesia's largest and most devastating eruption of the twentieth century, was a multi-phase explosive and effusive event that produced both basaltic andesite tephra and andesite lava (Self and Rampino, 2012). After a few days of felt earthquakes on 16 and 17 February 1963, explosive activity began at the summit on 18 February. This was followed the next day by the effusion of about 0.1 km3 of andesite lava which was extruded until 17 March 1963, when a large explosive eruption generated pyroclastic density currents (PDCs) and lahars that devastated wide areas N, SW, and SE of the volcano (figure 1) (Fontijn et al, 2015).

Figure (see Caption) Figure 1. Map of Gunung Agung and vicinity, eastern Bali, showing the extent of the 1963 lava flow (cross-hatched), pyroclastic flow deposits (stippled), and lahar deposits (dark shading) of the 1963–1964 eruption (after unpublished map courtesy of Indonesian Volcanological Survey). Sg is Siligading village, where many fatalities occurred. Reproduced from Self and Rampino (2012, figure 3).

Explosive activity continued intermittently until a second explosive phase of similar intensity occurred two months later, beginning on 16 May 1963 with reported ash plumes reaching 10 km above the 3-km-high summit (figure 2). This phase produced the greatest proportion of the pyroclastic flow material from the eruption and led to additional death and destruction in villages at the foot of the volcano (Self and Rampino, 2012). Explosive outbursts continued intermittently until 17 January 1964. The total death toll of the eruption was estimated between 1,100 and 1,900 (see references in Fontijn et al., 2015). A total estimated volume of erupted magma was ca 0.4 km3 (Self and Rampino, 2012).

Figure (see Caption) Figure 2. Photograph reported to be of the 16 May 1963 eruption column at Agung; the view is from the SW, perhaps near Rendang (shown on figure 1). Photo courtesy of the family of Denis Mathews, reproduced from Self and Rampino (2012, figure 2b).

Activity between 1964 and 2017. Almost no activity was reported from Agung during 1964-2017. Weak solfataric activity from within the summit crater was reported in 1989 (SEAN 14:07). MODVOLC thermal alerts were reported intermittently on one or two days during a few years (2001, 2002, 2004, 2006, 2008, 2012, 2013), but all of the alerts were located on the middle or lower flanks, suggesting their source was agriculture or forest fires, unrelated to volcanic activity. Chaussard et al. (2013) reported inflation centered on the summit at a rate of 7.8 cm/year between mid-2007 and early 2009, followed by slow deflation at a rate of 1.9 cm/year until mid-2011 (the last acquired data).

Summary of September-December 2017 Activity. Increases in seismic activity were first noted at Agung during mid-August 2017. Exponential increases in the rate of events during the middle of September led PVMBG to incrementally raise the Alert Level from I to IV (lowest to highest) between 14 and 22 September. Steam-and-gas emissions were intermittently observed 50-500 m above the summit crater from the end of September through October, with occasional bursts as high as 1,500 m. Seismicity dropped off almost as quickly as it rose, beginning on 20 October, and then continued a more gradual decrease through the end of the month and into November. The number and intensity of hot spots observed within the summit crater increased during September, then leveled off during October.

Ash emissions first appeared on 21 November, rising to 700 m above the summit. Ash density and heights of plumes increased several times during the rest of November to about 3,000 m. Ashfall as deep as 5 mm affected neighboring communities, and was reported several hundred kilometers from the summit; the international airport about 60 km SW was forced to close for a few days at the end of the month. Thermal data indicated effusion of lava into the summit crater at the end of November. After 30 November, emissions continued, primarily comprised of steam and gas, with intermittent plumes of dense ash, rising up to 2.5 km above the summit throughout December.

Activity during August-September 2017. In their monthly report of volcanic activity for August 2017, PVMBG noted that 49 volcanoes, including Agung, were listed at Alert Level 1, meaning "Normal", with no apparent increases in visual or seismic activity. The first signs of renewed unrest at Agung appeared as an increase in the rate of deep volcanic earthquakes (VA or Vulkanik Dalam) beginning on 10 August 2017. Shallow volcanic earthquakes (VB or Vulkanik Dangkal) began to increase two weeks later on 24 August, followed by an increase in the number of local tectonic earthquakes on 26 August (figure 3). Based on this increased seismicity, and an observation on 13 September of new solfataric activity at the bottom of the summit crater, PVMBG raised the Alert Level the following day from Level I (Normal) to Level II (Beware); the Aviation Color Code was raised to Yellow on a four-color scale (Green, Yellow, Orange, Red). The deeper earthquakes (VA) had a seismic amplitude range from 3-10 mm. The shallow earthquakes (VB) had an amplitude range of 2-7 mm. Otherwise, there was no surface expression of activity during September.

Figure (see Caption) Figure 3. Seismic activity at Agung between 1 July and 13 September 2017. The Y-axis is the number of daily earthquakes. The increase in deep volcanic seismicity (VA, or Vulkanik Dalam) that began on 10 August 2017 was followed two weeks later by an increase in shallow volcanic seismicity (Vulkanik Dangkal or VB). Courtesy of PVMBG (Peningkatan Tingkat Aktivitas Gunung Agung, 14 September 2017).

The Agung Volcano Observatory (AVO) is located in Rendang village about 8 km SW. Webcams are located in Rendang and in Bukit Asah, about 8 km W. On 15 September 2017 a steam emission was observed rising 50 m above the crater rim. The AVO issued a VONA on 18 September noting a rapid increase in volcanic earthquake activity with a small hot spot detected in satellite data. This contributed to them raising the Alert Level again to Level III (Standby), resulting in a 6-km-radius exclusion zone activated around the summit, extending to 7.5 km on the N, SE, and SSW flanks where the pyroclastic flows of 1963 had caused the most damage. Many of the 50,000 village residents within the 6 km exclusion zone began voluntary evacuations. The communities affected included Jungutan (7 km S) and Buana Giri (12 km SE) villages in the Bebandem District, Sebudi Village (6 km SW) in the Selat Subdistrict, Besakih Village (12 km SW) in the Rendang Subdistrict, and Dukuh (4 km NE) and Ban (7.5 km NW) villages in the Kubu Subdistrict. About 9,500 people had voluntarily evacuated from the villages by 22 September 2017.

The observatory issued another VONA on 19 September 2017, reporting an 'ash cloud' at 0255 UTC (1055 Central Indonesia Time, or WITA). It was described as a dense, white plume moving to the W. Around the same time (0240 UTC) MODVOLC recorded ten thermal alerts on the N and E flanks. Bali's Regional Disaster Management Agency (BPBD) reported in Antara News on 19 September that the source of the smoke and ash were forest fires caused by excessively dry conditions.

A VONA issued by AVO in the morning of 22 September stated that a steam emission about 50 m above the summit drifted NW. During the evening of 22 September, PVMBG raised the Alert Level to Level IV (Caution), the highest of the four-level scale, based primarily on continuing increases in seismicity. They expanded the exclusion zone to 9 km around the summit, and to 12 km in the areas S, SE, and NNE. The number of evacuees had risen to nearly 35,000 people by 24 September. Steam-and-gas plumes were intermittently observed rising to 200 m above the crater rim during the rest of September. By 26 September, PVMBG reported increasing seismic activity with 579 deep volcanic (VA) quakes, 373 shallow quakes (VB), and 50 local tectonic events that day. Seismicity continued to escalate through the end of the month. By the end of September, the government was assisting with the logistics of evacuating tens of thousands of livestock, primarily cattle, as well as over 90,000 people from within and around the 9 km exclusion zone. MAGMA Indonesia reported that new steaming and thermal areas within the summit crater expanded during the last week of the month.

Activity during October 2017. Narrow steam plumes rose 50-200 m above the summit crater during the first half of October. The rate of earthquakes during the last week of September and the first week of October continued to fluctuate at high levels, averaging 1-3 per minute, and more than 600 per day. By the first week of October, shallow earthquakes alone had increased to more than 200 per day, suggesting the possibility of magmatic activity at shallow depth. Satellite data showed increasing steam emissions along the NE edge of the crater rim. Tiltmeter data showed sudden deflation on 1 October, followed by continued inflation through 5 October. AVO released a VONA on 7 October noting a steam plume rising 1,500 m above the summit crater at 1245 UTC and drifting E (figure 4).

Figure (see Caption) Figure 4. A steam plume rose 1,500 m above the summit of Agung on 7 October 2017. Courtesy of PVMBG (Penurunan Status Gunungapi Agung, Bali Dari Level IV (awas) Ke Level III (siaga) Tanggal 29 Oktober 2017 Pukul 16.00 WITA).

During the second half of the month, steam plumes were denser and rose more frequently to 200-500 m above the summit crater. BNPB flew drones over the summit on 20 and 29 October 2017 and captured 400 aerial photographs (figures 5 and 6). The images revealed a widening of the fracture zone on the E side of the summit crater, and a new fracture on the SE side.

Figure (see Caption) Figure 5. A view into the summit crater of Agung on 20 October 2017, taken by a BNPB drone. Steam fumaroles rose from the NNE flank. N is to the left. Courtesy of PVMBG (Penurunan Status Gunungapi Agung, Bali Dari Level IV (awas) Ke Level III (siaga) Tanggal 29 Oktober 2017 Pukul 16.00 WITA).
Figure (see Caption) Figure 6. A view into the summit crater of Agung on 29 October 2017, taken by a BNPB drone. The steam plumes rose from the NE corner of the summit crater. The NE rim of the crater slopes away to the upper left. Courtesy of PVMBG (Penurunan Status Gunungapi Agung, Bali Dari Level IV (awas) Ke Level III (siaga) Tanggal 29 Oktober 2017 Pukul 16.00 WITA).

PVMBG noted a decline in seismicity beginning on 20 October 2017 which continued through the end of the month (figure 7), leading them to lower the Alert Level from IV to III on 29 October, and reduce the exclusion zone to a 6 km radius, plus a 7.5 km area in the NNE, SE and SSW sectors. In their late October report, they observed that remote sensing thermal infrared data had detected an increase in the thermal energy beginning on 10 July 2017, in the form of an increased number of hot spots within the summit crater. During August and September, the number of hot spots had increased significantly and correlated with the increases in seismicity (figure 8). The intensity of the thermal anomalies then decreased during October. Inflation resumed in mid-August and peaked in mid-September. After that, the GPS data indicated deflation at lower levels, but uplift of 6 cm occurred near the summit. The deformation rate slowed after 20 October.

Figure (see Caption) Figure 7. Daily seismic activity at Agung from 27 July-29 October 2017. Seismicity decreased noticeably on 20 October 2017, leading PVMBG to lower the Alert Level from IV to III on 29 October. Note that the vertical axis counting the number of daily seismic events ranges from 0 to 1,200, while in figure 3 the same axis ranges from 0 to 14. Courtesy of MAGMA Indonesia (Penurunan Status Gunungapi Agung, Bali dari Level IV (AWAS) ke Level III (SIAGA) Tanggal 29 Oktober 2017 pukul 16.00 WITA).
Figure (see Caption) Figure 8. Satellite thermal imagery from Citra-Sentinel 2 revealed an increase in the number and intensity of hotspots within the summit caldera of Agung during September 2017, followed by a decrease in early October. Courtesy of PVMBG (Penurunan Status Gunungapi Agung, Bali Dari Level IV (awas) Ke Level III (siaga) Tanggal 29 Oktober 2017 Pukul 16.00 WITA).

Activity during November 2017. For the first three weeks of November, dense white steam plumes rose 50-500 m above the summit crater. A VONA issued late on 11 November reported a 500-m-high steam plume. Seismicity continued at a much lower rate than during late September-October, with tens of daily events as opposed to hundreds.

The first ash emission of the current eruption occurred on 21 November at 1705 local time; the plume rose to 700 m and drifted ESE (figure 9). Trace amounts of ashfall were reported in the Pidpid-Nawehkerti area about 9 km SE. At the time of the first ash emission, BNPB reported the number of evacuees living in temporary housing at about 25,000. The emission was preceded by a low-frequency tremor. Multiple volcanic ash advisories were issued by the Darwin VAAC on 21 November, although the ash was not visible in satellite imagery due to weather clouds. Continuous tremor with 2-5 mm amplitude was recorded the following three days, and ash-and-steam emissions rose 300-800 m above the summit crater.

Figure (see Caption) Figure 9. The first reported ash emission from Agung in 53 years rose 700 m and drifted SE on 21 November 2017. Courtesy of PVMBG (Letusan Gunung Agung Selasa, 21 November 2017 Pukul 17.05 WITA).

A larger emission on 25 November sent black-gray ash plumes 2,000 m above the crater rim (figure 10) which then drifted W. The Darwin VAAC reported an ash plume visible in satellite imagery at 7.6 km altitude drifting WSW. Emissions continued later in the day, rising 4.6-6.7 km altitude and extending SE. Bright incandescence at the summit crater was observed that night. Ashfall was reported to the WSW in the villages of Menanga and Rendang (12 km SW) at the AVO Post, and also in Besakih Village, located in the upper part of Pempatan (8 km W). A number of international flights were cancelled from the I Gusti Ngurah Rai International Airport in Denpasar (60 km SW), affecting about 2,000 passengers, although the airport remained open.

Figure (see Caption) Figure 10. An ash emission rose at least 1,500 m above the summit of Agung on 25 November 2017 and drifted W. Courtesy of PVMBG (Letusan Gunung Agung 25 November 2017 Pukul 17:30 Wita).

Around 0545 local time the following day (26 November), the intensity of the ash emissions increased; the top of the plume reached 3,300 m above the summit at 1100 local time, and was drifting SE and E (figure 11). Ashfall was reported in many areas downwind including North Duda (9 km S), Duda Timur (12 km S), Pempetan, Besakih, Sideman (15 km SSW), Tirta Abang, Sebudi (6 km SW), Amerta Bhuana (10 km SSW), and some villages in Gianyar (20 km WSW) (figure 12). The largest amount, deposits 5 mm thick, was reported in Sibetan (11 km SSE). Trace amounts of ash were also reported much farther away, in Nusa Penida (an island 40 km S), Lombok (100 km ESE), and Sumbawa, 250 km E on the island of West Nusa Tenggara. Explosions from the crater were audible 12.5 km away that evening. Incandescence at the summit was observed from Bukit Asah and Batulompeh. The Darwin VAAC reported continuous ash emissions to 7.9 km altitude drifting SE throughout most the day, increasing to 9.1 km later in the day; ashfall was also reported at the international airport.

Figure (see Caption) Figure 11. A dense plume of ash rose 3,000 m above the summit of Agung and drifted ESE on 26 November 2017. Courtesy of PVMBG (Peningkatan Status Gunungapi Agung, Bali Dari Level III (siaga) Ke Level IV (awas), 27 November 2017).
Figure (see Caption) Figure 12. Ash from an eruption of Agung on 26 November 2017 covered garden plants in Jungutan Village, 7 km SE. Courtesy of Reuters.

The airport in Denpasar was forced to close during 27-29 November 2017. On those days ash drifted in multiple directions at different altitudes; it was observed drifting E at 9.1 km altitude, SW at 7.6 km altitude, and was moving S below 6.1 km. This increase in emissions led PVMBG to raise the Alert Level from III to IV on 27 November. Pictures and video showed a white steam plume adjacent to a gray ash plume rising from the crater, suggesting two distinct sources (figure 13).

Figure (see Caption) Figure 13. A white steam plume and dense gray ash both rose from the summit of Agung on 27 November 2017. Photo by K. Parwata, courtesy of Sutopo Purwo Nugroho, Twitter.

A single MODVOLC thermal alert appeared at the summit that day, along with a strong thermal anomaly in the MIROVA system data (figure 14) consistent with the appearance of new lava in the summit crater. The tiltmeter installed at the Yehkori station 4 km S of the summit showed continued inflation of up to 6 microradians between 22 and 27 November (figure 15). PVMBG also increased the exclusion zone to a radius of 8 km from the summit crater plus areas 10 km from the summit to the NNE, SE, S, and SW.

Figure (see Caption) Figure 14. A MIROVA plot of satellite infrared data for the year ending 23 February 2018 showed the first thermal anomaly from Agung in late November 2017, consistent with the emergence of lava in the summit crater. Courtesy of MIROVA.
Figure (see Caption) Figure 15. A steady inflation was measured by the tiltmeter located at the Yehkori station 4 km S of the summit of Agung between 22 November and 27 November. Courtesy of PVMBG (Peningkatan Status Gunungapi Agung, Bali Dari Level III (siaga) Ke Level IV (awas), 27 November 2017).

MAGMA Indonesia reported that beginning with the ash eruption on 21 November, lahars appeared in the Tukad Yehsa, Tukad Sabuh, and Tukad Beliaung drainages on the S flank, as well as Tukad Bara on the N flank. As of the end of November 2017, these lahars had impacted houses, roads, and agricultural areas. Although ash emissions increased, and lava was confirmed within the summit crater during the last week of November, the number of seismic events remained well below the values recorded during September and October (figure 16).

Figure (see Caption) Figure 16. Seismicity at Agung decreased significantly beginning on 20 October 2017 and remained well below 200 daily events throughout November, even though ash emissions began on 21 November. Courtesy of PVMBG (Peningkatan Status Gunungapi Agung, Bali Dari Level III (siaga) Ke Level IV (awas), 27 November 2017).

Ash emissions were reported by PVMBG rising to 3,000 m above the summit and drifting S on 27 November (figure 17). Continuing ash emission during 28-29 November rose to 2,000-4,000 m above the summit and drifted WSW (figure 18). Continuous seismic tremors were recorded during 28 November-1 December.

Figure (see Caption) Figure 17. Ash plumes from Agung rose to altitudes of around 6,000 m (3,000 m above the summit crater) and drifted S on 27 November 2017. Image courtesy of MAGMA Indonesia (Peningkatan Status Gunungapi Agung, Bali Dari Level Ill (SIAGA) ke Level IV (AWAS), 27 November 2017 10:07 WIB, Ir. Kasbani, M.Sc.).
Figure (see Caption) Figure 18. A dense plume of steam and ash rose from Agung and drifted away from this villager and his livestock on 28 November 2017. Courtesy of CNN.

With the increase in ash emissions during the last days of November 2017, satellite instruments also recorded significant releases of SO2 (figure 19). MAGMA Indonesia reported on 1 December that satellite data also recorded high temperatures consistent with new lava within the crater on 27, 28, and 29 November 2017. They estimated the volume of lava in the crater to be about 20 million cubic meters, equivalent to about a third of the total crater volume. The base of the ash-and-steam plumes was often reddish during 29 November-5 December reflecting incandescence from the lava in the crater (figure 20).

Figure (see Caption) Figure 19. The concentrations of SO2 emitting from Agung increased to levels that were easily detected by the Ozone Mapper Profiler Suite (OMPS) on the Suomi National Polar-orbiting Partnership (Suomi-NPP) satellite on 27 (top) and 28 (bottom) November 2017. The concentration of SO2 is measured in Dobson Units, a measure of the molecular density of the SO2 in the atmosphere. These NASA Earth Observatory images were created by Joshua Stevens, using OMPS data from the Goddard Earth Sciences Data and Information Services Center (GES DISC).
Figure (see Caption) Figure 20. Incandescence appeared at the base of the ash-and-steam plume at Agung on 29 November 2017, consistent with lava effusion in the summit crater. Courtesy of MAGMA Indonesia (Perkembangan Terkini Aktivitas Gunung Agung (1 Desember 2017 21:00 WITA), 2 December 2017 07:55 WIB, Ir. Kasbani, M.Sc.).

By 29 November, continuous ash emissions were rising to 6.4 km altitude and drifting from the SW towards the S, becoming diffuse over the Denpasar region (figure 21). The plume was observed moving E at the same elevation on 30 November, lowering to 5.5 km later in the day. Although emissions were primarily steam and gas beginning on 30 November, pilot reports on 1 December indicated ash was still visible SE of Agung, and steam-and-ash emissions were continuing. Steam-only emissions were reported on 2 December rising less than 1,000 m above the summit.

Figure (see Caption) Figure 21. Gas-and-ash emissions from Agung on 29 November 2017 were drifting both W and S in this false-color image generated by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite. The image uses a combination of shortwave infrared light and natural color, making it easier to differentiate between ash, clouds, and forest. The plumes appear to rise from two vents in the volcano's summit crater. Courtesy of NASA Earth Observatory.

Activity during December 2017. Steam, gas, and ash emissions continued throughout December 2017. During the first two weeks, emissions were primarily steam and gas, rising up to 2,000 m (figure 22), and incandescence was often observed at the summit. Dense gray ash emissions were observed, however, during 1-2 December. BNPB noted on 5 December that 63,885 evacuees were distributed in 225 evacuation shelters. On 8 December at 0759 a brief event generated a dense ash plume that rose 2.1 km above the crater rim and drifted W (figure 23). Minor amounts of ash were deposited on the flanks, and lapilli were reported in Temakung. A second ash plume rose 3 km at 1457 later that day.

Figure (see Caption) Figure 22. A burst of dense steam rose as high as 1,500 m from the crater of Agung on 5 December 2017 at 0848 local time (WITA) and drifted E, after which only a narrow diffuse plume remained. View is from the S. Courtesy of Sutopo Purwo Nugroho, Twitter.
Figure (see Caption) Figure 23. An eruption at Agung on 8 December 2017 at 0759 WITA sent a dense gray ash plume 2,100 m above peak to the W. View is from the S. Courtesy of Sutopo Purwo Nugroho, Twitter.

The Darwin VAAC reported multiple daily explosions during 8-15 December, creating ash plumes that drifted NW, W, and WSW at altitudes between 4.3 and 5.5 km. The explosions were visible in the webcams and from ground-based observers, and occasionally in satellite imagery when not blocked by weather clouds. VONA's were issued for events on 8 and 12 December. Multiple events during 11-12 December sent plumes rising up to 2.5 km above the crater rim and drifting NW and W (figure 24).

Figure (see Caption) Figure 24. A small ash emission rose from the crater of Agung during the early morning of 11 December 2017. Courtesy of Sutopo Purwo Nugroho, Twitter.

The Darwin VAAC reported larger ash emissions to 7.6 km altitude on 15 and 16 December interspersed with lower altitude (5.5-6.1 km) plumes. Continuing, regular discrete emissions during 16-17 December rose to 6.1 km and drifted WNW. An overhead image of the summit crater of 16 December revealed that, since a similar photo was taken on 20 October, new lava had filled about 1/3 of the crater with an estimated 30 million cubic meters of material (figure 25).

Figure (see Caption) Figure 25. Repeated overhead images of the Agung summit crater taken on 20 October and 16 December 2017 showed new lava filling about 1/3 of the crater with an estimated 30 million cubic meters of material. Posted on Twitter by Sutopo Purwo Nugroho for BNBP.

Discrete emissions to 5.5 km moving N and NNE were common during 18-21 December. Ash and steam drifted both E and W from the summit on 22 December. An ash emission on 23 December rose to 5.8 km and drifted NE, after which repeated emissions continued, rising to 4.6 km (figure 26). Ash fell on the flanks and in Tulamben, Kubu (9 km NE). In the morning of 24 December, a much larger plume drifting W at 10.7 km altitude was visible in satellite imagery. It dissipated after a few hours, and a separate plume was observed drifting NE at 5.5-5.8 km (figure 27); emissions continued throughout the day and into the next. PVMBG reported that the ash deposits from the NE-drifting plume were up to 3 mm thick (figure 28).

Figure (see Caption) Figure 26. An event at Agung on 23 December 2017 sent a dense, gray plume to 2,500 m above the crater rim at 1157 WITA. View is from a village on the W flank, likely about 7 km from the summit. Courtesy of Sutopo Purwo Nugroho, Twitter.
Figure (see Caption) Figure 27. Agung erupted steam and ash with a plume height of 2,000-2,500 m on 24 December 2017 at 1005 WITA. Courtesy of Sutopo Purwo Nugroho, Twitter.
Figure (see Caption) Figure 28. Map showing distribution and thickness of volcanic ash and lapilli from the ash emissions at Agung that began on 24 December 2017 at 1005 WITA. A thin layer of ash was deposited in a narrow NE trending band on the NE side of Agung. Courtesy of Sutopo Purwo Nugroho, Twitter.

As of 25 December, BNPB reported just over 70,000 evacuees spread out in 239 shelters. Discrete ash emissions continued through the end of the month rising as high as 2 km above the crater rim and drifting in several different directions. The last VAAC report of 2017 indicated an ash plume drifting W at 4.3 km altitude on 31 December.

References: Chaussard E, Amelung F, Aoki Y, 2013, Characterization of open and closed volcanic systems in Indonesia and Mexico using InSAR time series. J Geophys Res Solid Earth, 118:3957–3969. DOI: 10.1002/jgrb.50288.

Fontijn K, Costa F, Sutawidjaja I, Newhall C G, Herrin J S, 2015, A 5000-year record of multiple highly explosive mafic eruptions from Gunung Agung (Bali, Indonesia): implications for eruption frequency and volcanic hazards. Bull Volcanol, 77: 59. DOI: 10.1007/s00445-015-0943-x.

Self S, Rampino M, 2012, The 1963–1964 eruption of Agung volcano (Bali, Indonesia). Bull Volcanol 74:1521–1536. DOI: 10.1007/s00445-012-0615-z.

Information Contacts: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as Indonesian Center for Volcanology and Geological Hazard Mitigation, CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); Badan Nasional Penanggulangan Bencana (BNPB), National Disaster Management Agency, Graha BNPB - Jl. Scout Kav.38, East Jakarta 13120, Indonesia (URL: http://www.bnpb.go.id/); MAGMA Indonesia, Kementerian Energi dan Sumber Daya Mineral (URL: https://magma.vsi.esdm.go.id/); NASA Earth Observatory, EOS Project Science Office, NASA Goddard Space Flight Center, Goddard, Maryland, USA (URL: http://earthobservatory.nasa.gov/); NASA Goddard Space Flight Center (NASA/GSFC), Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Antara News (URL: https://bali.antaranews.com); Sutopo Purwo Nugroho, Twitter (URL: https://twitter.com/sutopo_pn); Cable News Network (CNN), Turner Broadcasting System, Inc. (URL: http://www.cnn.com/); Reuters (URL: http://www.reuters.com/).

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Eruptive History


There is data available for 5 Holocene eruptive periods.

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2017 Nov 21 2018 May 19 (continuing) Confirmed 3 Historical Observations Summit crater
1963 Feb 18 1964 Jan 27 Confirmed 5 Historical Observations
1843 Unknown Confirmed 5 Historical Observations
[ 1821 Mar 16 ] [ Unknown ] Uncertain 2  
1808 Unknown Confirmed 2 Historical Observations

Deformation History


There is data available for 1 deformation periods. Expand each entry for additional details.


Deformation during 2006 - 2009 [Uplift; Observed by InSAR]

Start Date: 2006 Stop Date: 2009 Direction: Uplift Method: InSAR
Magnitude: Unknown Spatial Extent: Unknown Latitude: Unknown Longitude: Unknown

Remarks: Shallow-sourced inflation at Agung has so far not resulted in eruption.

Figure (see Caption)

Averaged 2006?2009 LOS velocity map of the west Sunda volcanic arc, Indonesia, from ALOS InSAR time series, overlaying SRTM V4 DEM. Only pixels with a temporal coherence larger than 0.6 are shown. Black arrows: relative plate convergence rates at the Sunda trench (red line). Insets: zoom into 7 deforming volcanic centers, upper left: inflating volcanoes, lower right: deflating volcano.

From: Chaussard and Amelung 2012.


Reference List: Chaussard and Amelung 2012.

Full References:

Chaussard E, Amelung F, 2012. Precursory inflation of shallow magma reservoirs at west Sunda volcanoes detected by InSAR. Geophysical Research Letters, 39, L21311. https://doi.org/10.1029/2012GL053817

Emission History


There is no Emissions History data available for Agung.

Photo Gallery


An eruption column towers above Bali's Agung volcano on March 12, 1963. Five days later a devastating eruption produced pyroclastic flows and lahars that killed 1148 people. Another powerful eruption on May 16 caused additional fatalities. The eruption left tens of thousands homeless.

Photo by K. Kusumadinata, 1963 (Volcanological Survey of Indonesia).
See title for photo information.
An ash cloud rises above the summit crater of Agung volcano on March 17, 1963, during the first of two powerful explosive eruptions that caused much devastation to the island of Bali. The eruption began on February 19 as andesitic lava flowed down the northern flank. Major explosive eruptions on March 17 and May 16 produced devastating pyroclastic flows and lahars that killed more than 1100 people.

Photo by Djazuli, 1963 (Volcanological Survey of Indonesia).
See title for photo information.
The summit of Bali's Gunung Agung volcano contains a steep-walled, 500-m-wide, 200-m-deep crater that is the source of Agung's historical eruptions. Grayish layers of lava flows and brownish tephra layers from explosive eruptions are exposed in the crater wall.

Photo by Sumarna Hamidi, 1973 (Volcanological Survey of Indonesia).
See title for photo information.
The summit of Agung volcano marks the highest point on the island of Bali. The broad irregular volcanic massif in the far distance is the 11 x 6 km wide Bratan caldera in north-central Bali. Batukau, the largest of several post-caldera cones overtopping the southern rim, is the sharp peak at the left. Three lakes occupy the floor of Bratan caldera. Many of the cones are quite old, but some postdate the youngest dacitic pumice eruptions of Batur volcano (<23,000 years ago).

Photo by Sumarma Hamidi, 1973 (Volcanological Survey of Indonesia).
See title for photo information.
Agung volcano towers over the eastern end of the island of Bali. A steep-walled, 200-m-deep crater is located at the summit of the 3142-m-high volcano, seen here from the Sakta River on the eastern flank. Only three eruptions have been recorded in historical time from Gunung Agung; the latest, during 1963-64, produced devastating pyroclastic flows and lahars.

Photo by Tom Pierson, 1989 (U.S. Geological Survey).
See title for photo information.
Gunung Agung, Bali's sacred mountain, towers above rice fields near the Gunungapi Rendang volcano observation post of the Volcanological Survey of Indonesia. The 3142-m-high stratovolcano has erupted infrequently during historical time, but its 1963 eruption was one of the most devastating in Indonesia during the 20th century.

Photo by M.E. Ilyas, 1991 (Volcanological Survey of Indonesia).
See title for photo information.

Smithsonian Sample Collections Database


The following 7 samples associated with this volcano can be found in the Smithsonian's NMNH Department of Mineral Sciences collections, and may be availble for research (contact the Rock and Ore Collections Manager). Catalog number links will open a window with more information.

Catalog Number Sample Description Lava Source Collection Date
NMNH 116957-1 Scoria -- 1 Oct 1979
NMNH 116957-2 Scoria -- 1 Oct 1979
NMNH 116957-3 Lava -- --
NMNH 117584-1 Andesite -- --
NMNH 117584-2 Andesite -- --
NMNH 117584-3 Ash -- --
NMNH 117584-4 Andesite -- --

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