2017–2019 eruptions of Mount Agung explained

2017–2019 eruptions of Mount Agung
Start Date:[1]
Vei:3

Mount Agung, a volcano on the island of Bali in Indonesia, erupted five times in late November 2017, causing thousands to evacuate, disrupting air travel and causing environmental damage. As of 27 November 2017, the alert level was at its highest and evacuation orders were in place.

Tectonic earthquakes from the volcano had been detected since early August 2017, and volcanic activity intensified for several weeks before decreasing significantly in late October. A second, more violent period of major activity began in late November. Agung has since had eruptions in January, June, July and December 2018 and January, February, March, April, May and June 2019.

Background

1843 eruption

Agung erupted in 1843[2] as reported by Heinrich Zollinger:

1963 eruption

Mount Agung's 1963 eruption was among the most catastrophic volcanic events in Indonesian history. After initial explosions in the crater on 18 February of that year, lava began flowing down the mountain on 24 February, eventually travelling 7km (04miles) over the next three weeks. On 17 March, a highly explosive eruption occurred, reaching a VEI (Volcanic Explosivity Index) of 5 and sending lethal pyroclastic flows at high speeds down the mountain's slopes, killing at least 1,500 people.[3] Heavy rainfall mixed with ash from the eruption in the following days caused extensive lahars which killed about 200 more people. A smaller eruption occurred on 16 May, sending pyroclastic flows down the mountain once more, killing about 200 more people.[4] By the time the eruptions ceased in early 1964, they had claimed about 1,900 lives, marking the event as the 8th deadliest volcanic eruption of the 20th century.

Since 1963, the population of Bali has nearly doubled.[5] Mount Agung is therefore considered highly dangerous by Indonesian authorities. This concern was the primary reason behind their decision to evacuate more than 100,000 people in response to the surge in local tectonic activity in the latter half of 2017.

Major activity in 2017

August

Volcanic earthquakes were observed from 10 August 2017[6] and the intensity increased in the following weeks.

September

On 30 September 2017, an increase of rumbling and seismic activity around the volcano made people raise the alert to the highest level and about 122,500 people were evacuated from their homes around the volcano.[7] The Indonesian National Disaster Management Authority declared a 12km (07miles) exclusion zone around the volcano on 24 September.[8] A plume was observed on 13 September.

Evacuees gathered in sports halls and other community buildings around Klungkung, Karangasem, Buleleng, and other areas.[9] The monitoring station is in Tembuku, Rendang, Karangasem Regency, where intensity and frequency of tremors were monitored for signs of the imminent large eruption.[10]

The area experienced 844 volcanic earthquakes on 25 September, and 300 to 400 earthquakes by midday on 26 September. Seismologists have been alarmed at the force and frequency of the incidents as it has taken much less for similar volcanoes to erupt.[11] [12]

October

In late October 2017, the activity of the volcano decreased significantly, leading to lowering of the alert status on 29 October.[13]

The alert level remained at 3 (out of 4) until the start of the second major activity period, and plumes were observed during this time.[14] [15]

November

21 November

A small phreatic eruption was reported at 09:05 on 21 November (UTC), with the top of the ash cloud reaching 3842m (12,605feet) above sea level.[16] Thousands of people immediately fled the area,[17] and over 29,000 temporary refugees were housed in over 270 locations nearby.[18]

25 November

A magmatic eruption began early on Saturday morning, 25 November.[19] The eruption plume rose NaNkm (-2,147,483,648miles) above the summit crater, drifting towards the south and dusting the surroundings with a thin layer of dark ash, leading some airlines to cancel flights bound for Australia and New Zealand. An orange glow was later observed around the crater at night, confirming that fresh magma had reached the surface.[20] [21]

26 November

At 23:37 on 26 November (UTC), another eruption occurred. Ngurah Rai International Airport was closed next day,[22] leaving many tourists stranded.[23] More than 100,000 people in a 10km (10miles) radius of the volcano were ordered to evacuate.[24]

27 November

Sunday 26 November's eruption continued at a constant rate,[25] and lahars were reported in the Selat district south of the volcano. The Australian Government's Bureau of Meteorology reported that the top of the eruption column had reached an altitude of 9144m (30,000feet).[26] Ash continued to spread in a southeasterly direction, and estimates by the Pacific Disaster Center predicted that the resulting atmospheric ash exposure would affect up to 5.6 million people within the densely populated region surrounding the volcano.

29 November

Reductions in eruption intensity and wind dispersal of the ash cloud led authorities to reopen Ngurah Rai International Airport at 07:00 (UTC).[27] [28] Authorities also warned that the eruption volume could increase again at any time, potentially shutting down air traffic once more.

Activity in 2018

January

The volcano erupted once again on 11 January, sending plumes of smoke and ash, while Indonesia's Bali international airport was declared safe, operating normally.[29] The eruption column was reported to rise `2.5km (01.6miles) above the mountain.

June

Agung erupted on 12 June, sending plumes of smoke and ash some 2000m (7,000feet) above the volcano's summit.[30] No flights were affected from the event.

On 28 June, water vapour and volcanic ash emission were detected from Mount Agung up to 2km (01miles) into the air. The Ngurah Rai Airport was closed due to the event.[31] [32]

July

Agung erupted again 3 July due to a minor strombolian explosion. 700 people living near the crater were evacuated. No flights were affected.[33]

December

On the morning of 30 December, the volcano sent ash skywards as it erupted for about three minutes, spewing white clouds of smoke and ash more than 700m (2,300feet) into the air.[34] Several villages in Bali were covered in a thin layer of ash, but no smoke or lava was detected coming from the volcano and no evacuation has been ordered.[34]

Major activity in 2019

January

Agung erupted on 10 January, producing columns of volcanic ash. The summit of the volcano was covered by thick haze during eruption and thus the height of the ash could not be seen.[35]

February

On 22 February, volcanic ash plume that rose up to estimated 14000feet altitude or flight level 140

March

Explosive activity continues on 8 March or the day after Nyepi, with a volcanic ash plume that rose up to estimated altitude or flight level 120 and is moving at 10knot in south east direction.[36]

Mt. Agung erupted again on 28 March.[37] Bali's I Gusti Ngurah Rai International Airport operated normally despite the eruption, as the airspace above the airport was declared clear of volcanic ash based on a paper test.

April

A 2000adj=midNaNadj=mid high column of ash erupted out of Agung on 3 April 2019.[38] The Center for Volcanology and Geological Hazard Mitigation (PVMBG) maintained the volcano's alert level at "stay on alert", the third level of the four-tiered alert system. The center also set the danger zone at a 4km (02miles) radius from the crater.

May

In late May 2019 an eruption spewed lava and rocks over about 3km (02miles), with some ash fall on nearby villages and temporarily interrupting international flights.[39]

June

Another explosion occurred at the volcano at 13 June 2019, 01:38 local time. A Vulcanian eruption ejected much incandescent material to distances of at least 700m (2,300feet) from the crater and generated an ash plume that rose to 30000feet altitude and drifting south over Denpasar.

According to PVMBG, the eruption lasted almost 10 minutes, marking it one of the longest in the recent series of such Vulcanian explosions. A small earthquake swarm and slight inflation on 12 June 2019 preceded the eruption.

Impact

The 2017 eruption caused some 40,000 people to be evacuated from 22 villages around Mount Agung. It also caused surrounding airports to be closed. Lombok International Airport, on the neighboring island of Lombok, closed on 26 November, but was reopened the next morning,[40] only to be closed again on 30 November.[41] Lombok's airport reopened on 1 December. Ngurah Rai International Airport, located at the southern tip of the island and southwest of the volcano, closed on 27 November.[42] More than 450 flights were canceled and about 75,000 passengers were affected.[43] The airport was reopened on 29 November. This eruption also caused a decline in tourism on Bali by about 30%.

Notes and References

  1. 264020&vtab=Eruptions. Agung. 23 January 2018.
  2. http://e-journal.biologi.lipi.go.id/index.php/reinwardtia/article/view/249/758 Anwari Dilmy
  3. Zen. M. T.. Hadikusumo. Djajadi. December 1964. Preliminary report on the 1963 eruption of Mt.Agung in Bali (Indonesia). Bulletin of Volcanology. 27. 1. 269–299. 10.1007/BF02597526. 1964BVol...27..269Z. 128691551.
  4. News: Mount Agung: Bali volcano alert raised to highest level. 27 November 2017. BBC News. 28 November 2017.
  5. Web site: Population of Indonesia by Province 1971, 1980, 1990, 1995, 2000 and 2010. Badan Pusat Statistik. id. https://web.archive.org/web/20171203101151/https://www.bps.go.id/linkTabelStatis/view/id/1267. 3 December 2017. dead. 2017-12-01.
  6. Global Volcanism Program. Sennert. Sally Kuhn. Sally Kuhn Sennert. Report on Agung (Indonesia). Weekly Volcanic Activity Report, 13–19 September 2017. 28 November 2017. Smithsonian Institution and US Geological Survey. https://web.archive.org/web/20171201042537/http://volcano.si.edu/showreport.cfm?doi=GVP.WVAR20170913-264020. 1 December 2017. dead.
  7. News: Indonesian official: More than 120,000 flee Bali volcano. 28 September 2017. Fox News. 28 September 2017.
  8. Web site: Thousands evacuated as Bali volcano sparks fear. 24 September 2017. The Australian.
  9. News: Mount Agung: facts about Bali's imminent volcano eruption. 23 September 2017. UbudHood. 1 November 2017.
  10. News: How do experts know Mount Agung is about to erupt?. 25 September 2017. ABC News Australia. 1 November 2017.
  11. http://www.channelnewsasia.com/news/asiapacific/once-tremors-detected-bali-volcano-can-erupt-within-hours-9269148 Once tremors detected, Bali volcano can erupt within hours: Volcanologist
  12. News: Bali volcano eruption could be hours away after unprecedented seismic activity. Lamb. Kate. 26 September 2017. The Guardian. 26 September 2017. 0261-3077.
  13. News: Topsfield. Jewel. Rosa. Amilia. Mount Agung volcano alert in Bali downgraded. 27 November 2017. The Sydney Morning Herald. 30 October 2017.
  14. Global Volcanism Program. Sennert. Sally Kuhn. Sally Kuhn Sennert. Report on Agung (Indonesia). Weekly Volcanic Activity Report, 1–7 November 2017. 28 November 2017. Smithsonian Institution and US Geological Survey.
  15. Global Volcanism Program. Sennert. Sally Kuhn. Sally Kuhn Sennert. Report on Agung (Indonesia). Weekly Volcanic Activity Report, 8–14 November 2017. 28 November 2017. Smithsonian Institution and US Geological Survey.
  16. Web site: VONA . 27 November 2017 . https://web.archive.org/web/20180630000620/https://magma.vsi.esdm.go.id/vona/display?noticenumber=2017AGU15 . 30 June 2018 . dead .
  17. News: Bali's Mount Agung volcano erupts. 21 November 2017. BBC News. 21 November 2017.
  18. Regular bulletins are posted on the website of the Indonesian National Disaster Management Agency.
  19. News: Gunung Agung volcano (Bali, Indonesia): eruption has begun. 26 November 2017. Volcano Discovery. 15 September 2019.
  20. News: 'Get out now' 100,000 people told as Bali volcano continues to spew ash. 27 November 2017. Metro. 27 November 2017.
  21. News: A volcanologist explains Bali eruption photos. 27 November 2017. BBC News. 28 November 2017.
  22. Web site: Mount Agung eruption: Bali airport closed, flights cancelled . 27 November 2017 . Saifulbahri Ismail . CNA . 27 November 2017 . 27 November 2017 . https://web.archive.org/web/20171127032737/http://www.channelnewsasia.com/news/asiapacific/mount-agung-eruption-bali-airport-closed-flights-cancelled-9443114 . dead .
  23. News: Locals Watch As Lahars From Mount Agung Sweep Away Rice Fields. 27 November 2017. VIVA Indonesia. 27 November 2017. id.
  24. Web site: Mount Agung: Bali volcano alert raised to highest level . 27 November 2017 . BBC News Online . 27 November 2017.
  25. Web site: Life-saving technology provides alert as Bali's Mount Agung spews ash, raises alarm . 27 November 2017 . www.pdc.org. 28 November 2017. https://web.archive.org/web/20171201044413/http://www.pdc.org/news-n-media/pdc-updates/2017-Mount-Agung-Bali/. 1 December 2017. dead.
  26. Web site: Volcanic ash update for Mount Agung. 27 November 2017. Australian Government Bureau of Meteorology. 27 November 2017.
  27. News: Indonesia reopens Bali airport as wind clears volcanic ash. 29 November 2017. Reuters.com.
  28. News: Bali volcano: live updates on Mount Agung eruptions as airport reopens. 29 November 2017. Evening Standard.
  29. https://web.archive.org/web/20180111155759/http://www.xinhuanet.com/english/2018-01/11/c_136888943.htm Volcano erupts in Indonesia's Bali, airport remains safe
  30. News: Bali's Mount Agung erupts, shooting ash cloud into sky. PerthNow. 14 June 2018. 16 August 2020.
  31. News: Bali volcano eruption: Mount Agung spews volcanic ash triggering CLOSURE of airport. 29 June 2018. Express Newspapers. 29 June 2018.
  32. News: Mount Agung: Bali flight chaos continues as more airlines cancel. 29 June 2018. The West Australian. 29 June 2018.
  33. News: 700 flee 'thunderous' explosions and lava as Mount Agung erupts again. 3 July 2018. Australian Broadcasting Corporation.
  34. News: Bali's Mount Agung erupts again. News.com.au. 30 December 2018.
  35. Web site: Indonesia's Mount Agung volcano erupts again. The Straits Times. 11 January 2019.
  36. Web site: Agung volcano news & activity updates. 8 January 2019.
  37. Web site: Bali airport operations normal despite Mt. Agung eruption.
  38. Web site: Mount Agung erupts, spewing out 2,000-meter high column of ash.
  39. News: Mount Agung: Flights resume after Bali volcano disruption . BBC News . 25 May 2019 . 25 May 2019.
  40. Web site: Lombok International Airport closed due to volcanic ash from Mount Agung . 29 November 2017.
  41. Web site: Bali volcano: State of emergency EXTENDED as Lombok airport closed over dangerous ash . 30 November 2017 . 30 November 2017.
  42. Web site: Bali airport remains closed for a third day . 29 November 2017.
  43. Web site: Mount Agung: Bali Airport Closed And 75,000 Passengers Affected By Cancelled Flights . 29 July 2024 .