SUMATRA VOLCANOES AND THE DESTRUCTIVE ERUPTIONS OF SINABUNG AND MARAPI

VOLCANOES IN SUMATRA

Major active volcanoes on Sumatra Volcano Discovery

Sumatra’s landscape is heavily shaped by the Sunda Arc, a highly active tectonic zone responsible for a dense cluster of volcanoes spanning the island's western spine as well as numerous earthquakes in the region. The volcanoes range from towering, frequently active peaks to massive, ancient super-volcanic calderas. Notable volcanoes in Sumatra include

Mount Kerinci: in Jambi is the highest volcano in Indonesia. Standing at 3,805 meters (12,467 ft), it is a highly active stratovolcano known for its challenging, multi-day trekking trails.

Mount Marapi: is located in West Sumatra near Bukittinggi. It it is one of the Sumatra’s most active volcanoes. Its frequent eruptions regularly impact local air quality and surrounding highland towns.

Mount Sinabung: is located in North Sumatra. It famously erupted in 2010 after lying dormant for over 400 years. It has remained highly active, heavily altering the surrounding geography and farming communities.

Mount Sibayak: os also located near the town of Berastagi (about a two-hour drive from Medan) in North Sumatra, It is one of the island's most accessible peaks. It is frequently climbed for its unique sulfur craters and sweeping views.

Lake Toba is a massive lake in North Sumatra is a supervolcano caldera formed by a catastrophic eruption 74,000 years ago, which is believed to have altered the global climate.

Mount Talang is a 2597-meter- high (8,520 feet-high) stratovolcano that is a hiking destination because of its view of beautiful Twin Lakes and Lake Singkarak. It's one of the six active volcanoes in West Sumatra. It is said that the tea grown here tastes wonderful. The view is breathtaking and the weather is cool and pleasant.

Websites and Sources on Volcanoes: USGS Volcanoes volcanoes.usgs.gov ; Volcano World volcano.oregonstate.edu ; Volcanoes.com volcanoes.com ; Wikipedia Volcano article Wikipedia , Smithsonian Global Volcanism Program volcano.si.edu operated by the Smithsonian has descriptions of volcanoes around the globe and a catalog of over 8,000 eruptions in the last 10,000 years.

Kerinci Volcano

Kerinci volcano and a tea plantation in the fertile soil below it

At 3805 meters high (12,467 feet high), Gunng Kerinci is the highest peak in Sumatra and the highest volcano in Indonesia. It is popular with mountain climbers and lies at the heart of one the last refuses for nature and wildlife in Sumatra. The nearest village and climber’s base is Kersik Tuo, near Kayu Aro, Kerinci. The route is marked by signs, posted at half kilometer intervals.

Kerinci is a stratovolcano that has experienced numerous moderate explosive eruptions since its first recorded eruption in 1838. There were eruptions in 1838, 1842, 1874, 1878, 1908-09, 1921, 1923, 1936, 1936, 1937, 1938, 1952, 1960, 1963, 1964, 1966, 1967, 1968, 1969-70, 197, 1990, 1996, 1998, 1999, 2001-02, 2004, 2007, 2008, 2009. [Source: volcanodiscovery.com ~~]

Kerinci is capped by an unvegetated young summit cone that was constructed northeast of an older crater remnant. The volcano contains a deep 600-m-wide summit crater often partially filled by a small crater lake that lies on the northeast crater floor, opposite the SW-rim summit of Kerinci. The massive 13 x 25 kilometers wide volcano towers 2400-3300 meters above surrounding plains and is elongated in a N-S direction. ~~

Mt. Talang Eruptions

Talang volcano is a 2597-meter-high (8,520 foot-high stratovolcano that is) located 40 kilometers (25 miles) east of Padang, Sumatra. It forms a twin volcano with the extinct Pasar Arbaa volcano and has two crater lakes on its flanks.The largest of these is 1 x 2 kilometers wide Danau Talang. No historical eruptions have occurred from the summit of the volcano, which lacks a crater. All historical eruptions from Gunung Talang volcano have involved small-to-moderate 19th-century explosive activity originating from a series of small craters in a valley on the upper northeast flank. There were eruptions in 1833, 1843, 1845, 1868, 1963, 1967, 1968, 1986, 2001, 2005. The eruptions are generally small explosive eruptions. [Source: Volcano Discovery]

On the 2005 eruption, the BBC reported: “About 25,000 people have fled from the site of a volcano which has sprung to life on Indonesia's Sumatra island. The increasing activity on Mount Talang coincides with a string of earthquakes on Sumatra in recent weeks while the island was still struggling to cope after the 2004 tsunami, which killed at least 120,000 people in the Sumatra’s Aceh province. "The status of Mount Talang is now at top alert," local vulcanologist Surono told Reuters new agency. [Source: BBC, April 13, 2005]

Talang volcano in the 1870s

“The mountain was spewing ash 500 meters (1,640 feet) into the air, although not as forcefully as it was the day before, he said. Residents from villages around the volcano have now been evacuated, although many are reportedly returning to their homes during the day to tend their crops. "The volcano has not yet spewed lava from the crater, but in order to anticipate such an incident, we have evacuated those living around the mountain to safer areas," district chief Djamawan Fauzi told the Associated Press.

“Local villager Syafrudin described the volcano's sudden reawakening as "like the end of the world". "I first heard the rumble and then the ground started shaking... then there's smoke and sparks. We all ran in fear," he told Reuters. Indonesian President Susilo Bambang Yudhoyono is due to visit the region to try to calm the inhabitants' fears, his spokesman said.

“Scientists have warned of increased seismic activity in Indonesia, while the tectonic plates that make up the earth's crust realign following the magnitude 9 earthquake in December which caused the devastating tsunami. "The plates' movements release energy underground, and the energy could add to the activity of many volcanoes on Sumatra, but it doesn't mean this will trigger an eruption," said Surono. Indonesia, especially Sumatra, has suffered many aftershocks since the 26 December earthquake. A tremor on 28 March killed at least 1,200 people, many on the island of Nias, off Sumatra's west coast.

Sinabung

Sinabung is 2,460-meters (8,071 feet) high and located in northwestern Sumatra In August 2010, it erupted for the first time in 410 years, sending thousands of people into temporary shelters and disrupting flights. An eruption in 2014 killed 16 people. Mount Sinabung has erupted multiple times since 2014. In 2016, an eruption killed seven people again. Then in May 2019, a column of ash and smoke erupted some 6,500 feet into the air. Mount Sinabung is near Lake Toba, a 100 kilometre long volcanic crater that is the remnant of a catastrophic eruption about 70,000 years ago that was the largest eruption on Earth in last 2 million years.

Sumatra’s line of volcanoes parallel the Sumatra trench (Sunda Trench), where the oceanic Indo-Australian Plate subducts beneath the continental Eurasian Plate (the Sunda microplate); the geological boundary here drives intense geological activity, including the creation of the Sunda megathrust and the Great Sumatran fault, which generated the tsunami in December 2004 that killed over 220,000 people

Sinabung is located in the Karo Highlands, a beautiful area with a relatively cool climate and many trekking opportunities next to the town of Berastagi about 100 kilometers from Medan, Sumatra’s largest city. The two primary destinations of the highland are two volcanos: smoking 2094-meter-high Gunung Sibayak to the north and Gunung Sinabung to the west. The hike up Gunung Sibayak is very popular. There are three man routes up. The easiest and shortest way takes about three hours to traverse the seven kilometer distance. The climb up Gunung Sinabung takes six hours up and four hours back. Guides are recommended because it easy to get lost. One traveler died in a fall after getting lost in bad weather.

Sinabung volcano is a stratovolcano. Typical eruption style: Explosive. Eruptions: 2013-ongoing, 2010 There are no confirmed historic eruptions before the re-awakening in August 2010, but possibly it has had activity in around 1600 and 1881. It is evident that Sinabung volcano has frequently erupted on its flanks producing lava flows. Sinabung has four overlapping summit craters, where fumaroles have been active, particularly in 1912, but no eruption followed the increase of fumarolic activity then. The 4 summit craters are aligned along a N-S direction. The youngest crater of this andesitic-to-dacitic volcano is at the southern end of the four overlapping summit craters. [Source: volcanodiscovery.com ~~]

After the 2014 eruption, during which 30,000 people were evacuated, the Indonesian government banned anyone from living within a 6.9-kilometers (4.3-mile) radius of Mount Sinabung. Today the Guru Kinayan, Simacem, Kuta Gugung and Sibintun villages are still completely empty. Homes here are still coated in dusty, white ash. Green vegetation has taken over. When Associated Press photographer Binsar Bakkara visited the ghost villages in 2015, he said, The remains serve as “eerie reminders of how life suddenly stopped when the volcano erupted and everyone was forced to evacuate their homes,” Bakkara said. [Source: Emerald Pellot, In The KnowAugust 21, 2020]

Sinabung Erupts in 2010 after 410 Years

After no volcanic activity for more than four centuries, Mount Sinabung erupted in August 2010, leading to two deaths and displacing thousands living on its slopes. Apriadi Gunawan wrote in The Jakarta Post, “The eruption also led to the delay of several flights at Medan’s Polonia airport. N. Surbakti of Cinta Rakyat subdistrict reportedly died because of respiratory failure bought about by thick smoke. Reuters reported another death from a heart attack. Thousands of residents, forced to seek refuge at temporary shelters, complained of slow handling of emergency aid. They staged protests by blocking access roads to the Karo administration building, demanding food. About 50 tons of rice and 12,000 face masks have been supplied to temporary shelters. [Source: Apriadi Gunawan, The Jakarta Post, Medan, August 30 2010]

Sinabung in 2010

Eye witnesses said Mt. Sinabung erupted at two minutes past midnight with three explosions followed by a lava flow down the slope of the volcano. “We were shocked because the local administration had previously informed us that the volcano was stable. We panicked and fled our homes,” Sukanalu subdistrict head Paten Sitepu said. Lulled into a sense of calm by news of the stable condition, some residents who had fled their houses two days ago when the volcano first started spewing thick smoke decided to return home only to leave their houses again a few hours later when the volcano erupted.

Paten said he saw the volcano erupt and spew hot lava from its crater and send smoke and dust 1,500 meters into the air. North Sumatra Mining and Energy Agency head Untungta Kaban said this was the first eruption at Mt. Sinabung since 1600. “For almost 410 years the volcano showed no dangerous volcanic activity, which was why it was categorized as a dormant or type B volcano,” Kaban told The Jakarta Post.

The Volcanology and Geological Disaster Mitigation Center (PVMBG) announced that the eruption set a historical precedent. “This is the first time in our history that a type B volcano suddenly turned into a dangerous one, or a type A volcano,” PVMBG head Surono said after meeting with provincial officials Sunday. The center classifies type A volcanoes as having erupted at least once since 1600, type B as never having erupted since 1600, but showing signs of volcanic activity, and type C as never having erupted in recorded history. Surono said the PVMBG was studying why Sinabung erupted. “We never monitored the development of Mt. Sinabung because it was considered extinct,” Surono said. He added he would increase the monitoring activities on the volcano.

Residents in a 6-kilometer radius of the volcano have been instructed to leave their homes. At least 12,000 residents in three districts around the volcano have been evacuated to Kabanjahe and Brastagi in trucks and ambulances. They have been placed in eight shelters, including the regency administration building and other public places.

Sinabung 2014 Eruption Kills 16

The 2014 eruption and volcanic activity at Mount Sinabung killed 16 people. The volcano been erupted almost continuously for several months, producing frequent explosions, lava flows, and pyroclastic flows and repeatedly sent searing clouds of ash, gas, and volcanic debris down its slopes. By early 2014, volcanic activity had become a persistent threat to nearby communities. [Source: Associated Press, February 2014; AFP, February 3, 2014; Binsar Bakkara, Washington Post, February 1 2014]

Sinabung Spews Ash, Sulfur Dioxide in March 2021As the eruptions intensified, authorities evacuated more than 30,000 residents from villages surrounding the volcano. Displaced families were housed in temporary shelters, schools, public buildings, and tent camps while officials monitored the volcano’s behavior. Many evacuees endured difficult living conditions and became increasingly anxious to return home to care for farms, livestock, and property. The prolonged evacuation created social and economic hardships for thousands of people.

In late January 2014, volcanic activity appeared to decline, prompting authorities to reassess the danger. Nearly 14,000 residents living outside a designated five-kilometer (three-mile) exclusion zone were permitted to return to their homes. Officials believed that conditions had improved sufficiently to allow a partial return, although communities closer to the summit remained under evacuation orders. The decision reflected the challenge of balancing public safety with the needs of displaced residents.

However, on February 1, 2014, Sinabung suddenly produced a series of powerful eruptions that generated large pyroclastic flows extending up to five kilometers from the crater. Thick ash blanketed villages, farmland, and forests, turning the surrounding landscape gray. Following the eruption, all residents who had been allowed to return were ordered back to evacuation centers. The disaster highlighted the unpredictable nature of volcanic activity and the difficulties involved in determining when it is safe for people to return to hazardous areas.

People Killed by the 2014 Mount Sinabung Eruptions

The February 2014 eruption claimed the lives of 16 people, making it the deadliest phase of Sinabung’s renewed activity. Most of the victims were caught by fast-moving clouds of superheated gas, ash, and volcanic debris known as pyroclastic flows. These flows swept across areas near the volcano, causing fatal burns and suffocation. Rescue teams initially recovered 14 bodies, while additional victims were found or later died from their injuries. [Source: Associated Press, February 2014; AFP, February 3, 2014; Binsar Bakkara, Washington Post, February 1 2014]

Among those killed were four high-school students and their teacher, who had traveled to the mountain to observe the eruptions. A local television journalist also died while covering the volcanic activity. Many of the victims were located within the officially designated danger zone, an area that authorities had warned people to avoid. Rescue workers later discovered charred motorcycles buried beneath volcanic ash, suggesting that several victims had been attempting to flee when the pyroclastic flows overtook them.

Search-and-rescue operations were hampered by continuing volcanic activity and dangerous conditions. Rescuers worked in areas covered with thick ash and exposed to the risk of additional eruptions. At times, operations had to be temporarily suspended to protect emergency personnel from new explosions and falling volcanic material. Despite extensive searches, officials initially feared that the death toll could rise further because several people had been reported missing.

The tragedy underscored the extreme danger posed by pyroclastic flows, which can travel rapidly and leave little opportunity for escape. Although authorities had maintained an exclusion zone around the volcano, some residents and visitors entered hazardous areas despite repeated warnings. The deaths prompted renewed calls for stricter enforcement of evacuation orders and greater public awareness of volcanic hazards. The eruption became one of Indonesia’s most significant volcanic disasters of the decade and demonstrated the risks faced by communities living near the country's many active volcanoes.

Folklore Helps Explain Why Sinabung Returned to Life

Reporting from Kabanjahe, Ben Otto wrote in the Wall Street Journal, “Scientists can’t explain precisely why Indonesia’s Mount Sinabung – quiet for centuries – is now one of the world’s most active volcanoes. Many locals, however, point to folklore to offer one explanation: the mountain is angry. Government volcanologists say they have little way of knowing what Sinabung might be capable of. Evacuees at different shelters have their own theories: perhaps someone swore while climbing to the peak, perhaps unwed youth are engaged in sexual exploits at the lake northeast of the mountain. [Source: Ben Otto, Wall Street Journal, February 3, 2014 \~]

“Some Muslims in this largely Christian region of the world’s most Muslim-populous country worry that someone cooked meat that was haram – forbidden by Islamic law – or that too few of them pray regularly. “Most of us didn’t pray five times a day,” said Sistari Barugintang, who has been living at the city’s largest mosque in Kabanjahe, the district headquarters, since November. Her house now sits under a layer of ash less than four kilometers from the peak. “We’re all praying now,” she said. \~\

“In local folklore, Sinabung is guarded by the spirit of a woman of uncommon purity. Years ago, one tale goes, a young woman of good heart, who lived in the Karo region around the volcano, grew frustrated with her family and ran away to the mountain. There she changed into a spirit that now guards Sinabung, bringing the wind and rain and clouds whenever someone offends her. For many locals, hiking the 2,500-meter massif—as they often did before the volcano sprang to life late last year—meant leaving offerings of cigarettes and other goods to the mountain spirit. \~\

“A guide and resident of Berastagi, the highlands town east of the volcano, tells the story of a group of university students from nearby Medan who hiked up the volcano a few years ago in search of edelweiss, a white mountain flower. One young man in the group was openly contemptuous of local tales about the mountain; he swore as he climbed, littering whenever they stopped for snacks. At a camp about 500 meters below the summit, the group went off to look for the flower, and the young man was separated from the others when a cloud rolled in. When he didn’t return to the camp later, the group went looking for him. All they found were his shoes and shirt. “He probably went mad,” the guide said. “Spiritual leaders say he’s still up there on the mountain, but that he no longer looks like us. One day he’ll resume human form and return home, but he’ll be an old man and not even his family will recognize him.” \~\

Powerful Sinabung Eruption in 2015

The lava dome at Mount Sinabung continued to grow during its prolonged eruptive phase, periodically collapsing and generating dangerous pyroclastic flows that swept down the volcano’s slopes. These fast-moving mixtures of hot gas, ash, and rock posed a constant threat to nearby communities and prompted repeated evacuation orders. The long duration of the eruption, however, made it increasingly difficult to persuade residents to leave their homes. According to local officials, only about one-third of those living in affected areas voluntarily relocated to temporary shelters, despite the continuing danger. [Source: Associated Press, June 12, 2015; Wired, June 16, 2015]

On one occasion, in June 2015, Sinabung produced a powerful eruption that sent volcanic ash high into the atmosphere and triggered a series of hot ash avalanches. Authorities had already raised the volcano’s alert status to its highest level because of the growing instability of the lava dome near the summit. Monitoring officials reported that hot ash traveled as far as three kilometers down the southeastern slopes, while volcanic ash rose up to two kilometers into the sky. Scientists warned that additional collapses of the lava dome could occur without warning.

The Indonesian government closely monitored the volcano and maintained a danger zone extending seven kilometers from the crater. More than 2,700 residents from villages within this exclusion area were evacuated to temporary shelters as a precaution. Although no injuries or fatalities were reported from these particular eruptions, officials emphasized that the threat remained significant due to the possibility of sudden pyroclastic flows and further explosive activity.

Mount Marapi 2023 Eruption Kills 24 Hikers

Mount Marapi is the most active volcano on the island of Sumatra and one of Indonesia’s most closely monitored volcanoes. Rising to about 2,891 meters (9,500 feet), the volcano is surrounded by densely populated areas, including the cities of Bukittinggi, Padang Panjang, and Batusangkar. Its name, meaning “Mountain of Fire,” reflects its long history of eruptions and volcanic activity. Marapi is part of Indonesia’s vast network of active volcanoes located along the Pacific Ring of Fire, a region characterized by frequent earthquakes and volcanic eruptions. [Source: Heather Chen, Jamal Jamaluddin and Manveena Suri, CNN, December 4, 2023; Irwanda Saputra, AFP, December 4, 2023; Reuters, December 5, 2023]

On December 3, 2023, Mount Marapi erupted suddenly, sending a column of volcanic ash approximately 3,000 meters (10,000 feet) into the atmosphere. The eruption produced large clouds of ash that drifted across nearby districts, reducing visibility and covering roads, vehicles, buildings, and farmland in gray volcanic dust. Ashfall reached surrounding communities and even affected larger urban areas in West Sumatra.

Authorities raised the volcano’s alert status and established an exclusion zone around the crater to reduce the risk to residents and visitors. The eruption occurred while dozens of hikers were on the mountain. At the time, approximately 75 climbers were reported to be on Marapi’s slopes despite long-standing recommendations from volcanologists that people should stay several kilometers away from the crater.

Search-and-rescue teams were immediately deployed, but their work was complicated by continuing eruptions, ash emissions, and hazardous conditions near the summit. Officials warned that lava flows, volcanic debris, and additional eruptions remained possible.

Volcanologists noted that Mount Marapi can be particularly difficult to monitor because it often shows few clear seismic warning signs before erupting. Although the volcano had erupted several times earlier in 2023, experts said its behavior remained unpredictable. Indonesian volcanology officials stated that warnings against climbing near the summit had been issued repeatedly over the years. The eruption became the deadliest event at Marapi since 1979, when an eruption killed 60 people.

Deaths from the Mount Marapi 2023 Eruption

The December 2023 eruption claimed the lives of 24 hikers who were caught near the volcano’s summit. Most of the victims were located close to the crater, where they were exposed to volcanic ash, hot gases, and eruptive debris. Rescue workers initially recovered 11 bodies, while additional victims were discovered during subsequent search operations. Several survivors were also found with burns, fractures, and other injuries caused by the eruption. [Source: Heather Chen, Jamal Jamaluddin and Manveena Suri, CNN, December 4, 2023; Irwanda Saputra, AFP, December 4, 2023; Reuters, December 5, 2023]

Rescue efforts were extremely challenging because the volcano remained active after the initial eruption. Teams of rescuers climbed the mountain on foot and carried injured hikers down steep slopes while ash continued to fall. Helicopter operations were not possible because volcanic ash and ongoing eruptions created dangerous flying conditions. Search operations sometimes had to be paused temporarily when volcanic activity increased.

Among the survivors was a 19-year-old student who became widely known after recording a video message while stranded on the mountain. Covered in ash and suffering burns, she appealed for help before eventually being rescued and transported to a hospital. Other survivors reported being trapped in darkness as ash clouds swept across the summit area. Many suffered psychological trauma in addition to physical injuries.

The tragedy prompted questions about why hiking was still permitted on the volcano despite repeated warnings from volcanologists. Officials from Indonesia’s volcanology agency stated that they had advised for years that climbers should remain at least three kilometers from the crater. The disaster highlighted the dangers of recreational activity on active volcanoes and renewed calls for stricter enforcement of safety restrictions in hazardous areas.

Lahars After Mount Marapi 2023 Eruption Kill 37

Several months after the December 2023 eruption, heavy rainfall triggered deadly lahars on the slopes of Mount Marapi. Lahars, sometimes referred to as “cold lava flows,” are fast-moving mixtures of water, volcanic ash, sand, rocks, and other debris that flow downhill along river channels. These volcanic mudflows are a common hazard after eruptions because loose ash and debris can be mobilized by intense rainfall. The deposits left by Marapi’s eruption created ideal conditions for destructive lahars during the rainy season. [Source: Heather Chen and Lucas Lilieholm, CNN, May 13, 2024]

In May 2024, torrential rains generated lahars and flash floods that swept through several districts in West Sumatra. Thick mud, volcanic debris, and floodwaters inundated roads, bridges, homes, and agricultural land. Entire communities near the volcano were affected as rivers overflowed and carried large quantities of volcanic sediment downstream. The disaster demonstrated that volcanic hazards can continue long after an eruption has ended.

At least 37 people were killed in the floods and lahars, while many others were injured or displaced. Most of the fatalities occurred in Agam Regency and neighboring districts, where rapidly moving mudflows overwhelmed communities. Search-and-rescue teams worked through difficult conditions to recover victims and assist survivors. Numerous residents were forced to evacuate as authorities assessed ongoing risks from flooding and unstable volcanic deposits.

The lahars also caused extensive infrastructure damage. More than 80 houses and at least 16 bridges were damaged or destroyed, disrupting transportation and communications in affected areas. The disaster highlighted the long-term dangers associated with active volcanoes, particularly in tropical regions where heavy rainfall can transform volcanic ash and debris into deadly mudflows. For communities around Mount Marapi, the impacts of the 2023 eruption continued well beyond the initial volcanic event.

Image Sources: Wikimedia Commons

Text Sources: “Encyclopedia of World Cultures Volume 5: East/Southeast Asia:” edited by Paul Hockings, 1993; “Culture and Customs of Indonesia” by Jill Forshee, Greenwood Press, 2006; National Geographic, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Encyclopedia.com, Library of Congress, Indonesia Tourism website (indonesia.travel), Indonesia government websites, Live Science, The Conversation, The New Yorker, Time, BBC, CNN, Reuters, Associated Press, AFP, Lonely Planet Guides, Google AI, Wikipedia, The Guardian and various websites, books and other publications.

Last updated May 2026