Mount Merapi, Gunung Merapi (literally Fire Mountain in Indonesian and Javanese), is an active stratovolcano located on the border between Central Java and Special Region of Yogyakarta provinces, Indonesia. It is the most active volcano in Indonesia and has erupted regularly since 1548. It is located approximately 28 kilometres north of Yogyakarta city which has a population of 2.4 million, and thousands of people live on the flanks of the volcano, with villages as high as 1,700 metres above sea level.
Smoke can often be seen emerging from the mountaintop, and several eruptions have caused fatalities. Pyroclastic flow from a large explosion killed 27 people on 22 November 1994, mostly in the town of Muntilan, west of the volcano. Another large eruption occurred in 2006, shortly before the Yogyakarta earthquake. In light of the hazards that Merapi poses to populated areas, it has been designated as one of the Decade Volcanoes.
On 20 October 2010, the Indonesian government raised the alert for Mount Merapi to its highest level and warned villagers in threatened areas to move to safer ground. People living within the range of a 20 km zone were told to evacuate. Officials said about 500 volcanic earthquakes had been recorded on the mountain over the weekend of 23–24 October, and that the magma had risen to about 1 kilometre below the surface due to the seismic activity. On the afternoon of 25 October 2010, Mount Merapi erupted lava from its southern and southeastern slopes.
The mountain was still erupting on 30 November 2010, but due to lowered eruptive activity on 3 December 2010, the official alert status was reduced to level 3. The volcano is now 2930 metres high, 38 metres lower than before the 2010 eruptions. After a large eruption in 2010, the characteristic shape of Mount Merapi was changed. On 18 November 2013, Mount Merapi erupted smoke up to 2,000 meters high, one of its first major phreatic eruptions after the 2010 eruption. Researchers said that this eruption occurred due to the combined effect of hot volcanic gases and abundant rainfall. The most recent eruptions so far were on 3 March 2020 and 27 March 2020.
In April 2006, increased seismicity at more regular intervals and a detected bulge in the volcano’s cone indicated that fresh eruptions were imminent. Authorities put the volcano’s neighboring villages on high alert and local residents prepared for a likely evacuation. On 19 April smoke from the crater reached a height of 400 metres, compared to 75 metres the previous day. On 23 April, after nine surface tremors and some 156 multifaced quakes signalled movements of magma, some 600 elderly and infant residents of the slopes were evacuated.
By early May, active lava flows had begun. On 11 May, with lava flow beginning to be constant, some 17,000 people were ordered to be evacuated from the area and on 13 May, Indonesian authorities raised the alert status to the highest level, ordering the immediate evacuation of all residents on the mountain. Many villagers defied the dangers posed by the volcano and returned to their villages, fearing that their livestock and crops would be vulnerable to theft. Activity calmed by the middle of May.
On 27 May, a 6.3 magnitude earthquake struck roughly 50 km southwest of Merapi, killing at least 5,000 and leaving at least 200,000 people homeless in the Yogyakarta region, heightening fears that Merapi would “blow”. The quake did not appear to be a long-period oscillation, a seismic disturbance class that is increasingly associated with major volcanic eruptions. A further 11,000 villagers were evacuated on 6 June as lava and superheated clouds of gas poured repeatedly down its upper slopes towards Kaliadem, a location that was located southeast of Mt. Merapi. The pyroclastic flows are known locally as “wedhus gembel” (Javanese for “shaggy goat”). There were two fatalities as the result of the eruption.
In late October 2010 the Center for Volcanology and Geological Hazard Mitigation, Geological Agency (CVGHM), (Indonesian language—Pusat Vulkanologi & Mitigasi Bencana Geologi, Badan Geologi-PVMBG), reported that a pattern of increasing seismicity from Merapi had begun to emerge in early September.
Observers at Babadan 7 kilometres west and Kaliurang 8 kilometres south of the mountain reported hearing an avalanche on 12 September 2010. On 13 September 2010 white plumes were observed rising 800 metres above the crater. Lava dome inflation, detected since March, increased from background levels of 0.1 millimetres to 0.3 millimetres per day to a rate of 11 millimetres per day on 16 September. On 19 September 2010 earthquakes continued to be numerous, and the next day CVGHM raised the Alert Level to 2 (on a scale of 1–4). Lava from Mount Merapi in Central Java began flowing down the Gendol River on 23–24 October signalling the likelihood of an imminent eruption.
On 25 October 2010, the Indonesian government raised the alert for Mount Merapi to its highest level and warned villagers in threatened areas to move to safer ground. People living within a 10 kilometres zone were told to evacuate. The evacuation orders affected at least 19,000 people; however, the number that complied at the time remained unclear to authorities. Officials said about 500 volcanic earthquakes had been recorded on the mountain over the weekend of 23–24 October, and that the magma had risen to about 1 kilometre below the surface due to the seismic activity.
After a period of multiple eruptions considered to exceed the intensity and duration of those in 1872 on 10 November 2010 the intensity and frequency of eruptions was noticed to subside. By this time 153 people had been reported to have been killed and 320,000 were displaced. Later the eruptive activities again increased requiring a continuation of the Level 4 alert and continued provision of exclusion zones around the volcano. By 18 November the death toll had increased to 275. The toll had risen to 324 by 24 November and Syamsul Maarif, head of the National Disaster Mitigation Agency (BNPB) explained that the death toll had risen after a number of victims succumbed to severe burns and more bodies were found on the volcano’s slopes.
In the aftermath of the more intensive eruptive activities in late November, Yogyakarta’s Disaster Management Agency reported that there were about 500 reported cases of eruption survivors in Sleman district suffering from minor to severe psychological problems, and about 300 cases in Magelang. By 3 December the death toll had risen to 353.
On Friday, 3 December 2010, the head of the National Disaster Management Agency (BNPB), Dr. Syamsul Maarif, M. Si, accompanied by the head of the Centre for Volcanology and Geological Hazard Mitigation CVGHM (PVMBG), Dr. Surono made a joint press release at the BNPB Command Post in Yogyakarta. As of 3 December 2010, at 09.00 am, the CVGHM (PVMBG) lowered the status of Mount Merapi to the level of Caution Alert (Level III). They clarified that with this alert level the potential of hot ash clouds and projected incandescent material remained. The Geological Agency provided several recommendations including that there would be no community activities in the disaster prone areas and proclaimed an ongoing exclusion zone of 2.5 kilometres radius.
A phreatic eruption began on the morning of 11 May 2018, prompting the evacuation of areas within a 5-kilometre radius of the volcano. Adisutjipto International Airport in Yogyakarta was closed due to the eruption’s ash plume.