Mount Merapi
Indonesia's Most Active and Deadly Stratovolcano
Elevation
2,910 m
Last Eruption
2020–present (ongoing)
Type
Stratovolcano
Country
Indonesia
Location
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Volcanic Hazards & Risk Assessment
Primary Hazards
- Pyroclastic flows
- Lava flows
- Volcanic bombs and ballistics
- Lahars and mudflows
Risk Level
Population at RiskHigh
Infrastructure RiskHigh
Aviation RiskSignificant
Geological Composition & Structure
Rock Types
Primary
Unknown
Silica Content
Varied composition
Tectonic Setting
Unknown
Intraplate setting with hotspot or regional volcanic activity.
Age & Formation
Epoch
Unknown
Evidence
Unknown
Eruption Statistics & Analysis
| Metric | Value | Global Ranking | Significance |
|---|---|---|---|
| Total Recorded Eruptions | Unknown | Low | Moderately active volcano |
| Maximum VEI | VEI Unknown | Minor | Local impact potential |
| Recent Activity | 6 years ago | Very Recent | Currently active |
Monitoring & Alert Status
Monitoring Networks
Global Volcanism Program
International eruption database
Current Status
Active
Recent volcanic activity detected. Continuous monitoring in place.
Authority Sources
Related Volcanoes
Camille Bismonte
via Unsplash
Galang Daeng Sena
via Unsplash
Other Volcanoes in Indonesia
- Gamalama
Stratovolcano(es)
- Karangetang
Stratovolcano
- Kelud
Stratovolcano
- Krakatau
Caldera
Interesting Facts
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Merapi has 106 confirmed eruptions in the Smithsonian database — more than almost any other volcano on Earth, with an average of one significant eruption every 4–5 years since 1548.
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The term 'Merapi-type pyroclastic flow' is an internationally recognized volcanological term describing block-and-ash flows generated by gravitational dome collapse.
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The 2010 eruption killed 367 people, including Mbah Maridjan, the cultural guardian (juru kunci) of Merapi, whose death became a national mourning event in Indonesia.
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Approximately 1.3 million people live within Merapi's officially designated hazard zones, with the city of Yogyakarta (3.7 million metro) just 28 km to the south.
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Merapi's lava dome can grow by over 100,000 cubic meters per day during active phases — roughly equivalent to filling an Olympic swimming pool every 30 seconds.
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The 1930 eruption killed approximately 1,300 people and led to the establishment of Indonesia's first permanent volcano monitoring network.
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The Borobudur Temple, the world's largest Buddhist monument, and Prambanan Temple, a UNESCO World Heritage Site, both sit within the potential ashfall zone of a major Merapi eruption.
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Sand mining of Merapi's volcanic deposits is a major local industry, with trucks carrying volcanic sand and gravel operating on the flanks year-round.
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During the 2010 eruption, pyroclastic flows traveled over 15 km from the summit — far exceeding the 5–8 km distance assumed by the then-current hazard maps.
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The Yogyakarta Sultanate holds an annual Labuhan ceremony offering gifts to the volcano's spiritual forces, a tradition maintained for centuries.
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Merapi's name translates literally as 'Fire Mountain' from the Javanese words 'meru' (mountain) and 'api' (fire).
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The volcano shares its name with Marapi on Sumatra — an entirely different volcano — leading to occasional confusion in international media reports.
Frequently Asked Questions
Is Mount Merapi still active?
Yes, Mount Merapi is not only still active but is currently in an ongoing eruptive phase that began in December 2020. As of 2025, the summit lava dome continues to grow and periodically collapse, generating pyroclastic flows and triggering lahars during the rainy season. BPPTKG, Indonesia's geological hazard agency, maintains the alert at elevated levels and operates one of the densest volcano monitoring networks in the world around Merapi. The volcano has produced 106 confirmed eruptions in recorded history, with significant events occurring on average every 4–5 years since the sixteenth century. It is classified as the most active volcano in Indonesia, a country with 101 Holocene volcanoes.
When did Merapi last erupt?
Merapi's current eruption began on 31 December 2020 and is ongoing as of 2025, making it one of the volcano's sustained eruptive episodes. The most recent major eruption prior to this was the catastrophic VEI 4 event of October–November 2010, which killed 367 people, displaced 350,000, and caused approximately USD 600 million in damage. The 2010 eruption was the largest at Merapi in over a century and significantly exceeded the reach predicted by existing hazard maps. Between the 2010 and current eruptions, notable activity also occurred in 2013 (VEI 3) and 2018 (VEI 3), consistent with Merapi's pattern of erupting every few years.
How many people has Merapi killed?
Mount Merapi has killed more than 2,600 people in documented eruptions since the sixteenth century. The deadliest events include the 1672 eruption (approximately 3,000 killed according to historical accounts, though this figure is uncertain), the 1930–1931 eruption (approximately 1,300 killed by pyroclastic flows), and the 2010 eruption (367 killed). Additional hundreds of casualties are recorded across dozens of smaller eruptions over the past five centuries. The high death tolls reflect Merapi's combination of frequent dome-collapse pyroclastic flows and the extremely dense population on its lower flanks, where approximately 1.3 million people live within designated hazard zones.
What type of volcano is Merapi?
Merapi is an active stratovolcano (also called a composite volcano), built from alternating layers of lava flows and pyroclastic deposits. Its eruption style is dominated by the extrusion and collapse of viscous andesitic lava domes at the summit. When the dome becomes gravitationally unstable or is disrupted by explosive activity, it collapses to produce fast-moving pyroclastic density currents known as 'Merapi-type' block-and-ash flows — a term used in volcanological literature worldwide. The andesitic magma (52–58 percent silica) is intermediate in composition, making it viscous enough to build domes but gas-rich enough to drive explosive collapses. Merapi's eruption style is characteristic of subduction-zone stratovolcanoes along the Sunda volcanic arc.
How tall is Mount Merapi?
Mount Merapi stands at approximately 2,910 m (9,551 ft) above sea level, though the summit elevation fluctuates by tens of meters over time as the active lava dome grows and collapses. The 2010 eruption, for example, reduced the summit height by roughly 38 m when the dome was explosively destroyed. Merapi rises approximately 2,400 m above the Yogyakarta plain to the south. It is not the tallest volcano in Java — that distinction belongs to Semeru at 3,657 m — but its proximity to a major metropolitan area and extreme eruption frequency make it far more dangerous than taller but less active peaks.
Can you visit Mount Merapi?
Yes, though access depends on the volcano's current alert level. When activity is low (Level I or II), guided overnight treks from the village of Selo on the northern flank reach the summit in 4–5 hours, typically departing at midnight for a sunrise arrival. During elevated activity (Level III–IV, which has been the case for much of the 2020–present eruption), summit access is prohibited. Alternative experiences include the popular 'Lava Tour' by off-road vehicle through pyroclastic flow devastation zones, the Merapi Museum near Kaliurang, and memorial sites from the 2010 eruption. Yogyakarta, just 28 km south, is the base for all Merapi visits and also offers access to the Borobudur and Prambanan World Heritage Sites.
What happened in the 2010 Merapi eruption?
The 2010 eruption began on 26 October and escalated to a VEI 4 paroxysm on 5 November — Merapi's largest eruption in over a century. Pyroclastic flows raced over 15 km down the Gendol River valley, far exceeding the predicted hazard zones. The eruption killed 367 people, including Mbah Maridjan, the cultural guardian of the volcano who refused to evacuate. Some 350,000 people were evacuated in one of Indonesia's largest-ever volcanic evacuations. The eruption column reached 17 km altitude, ashfall blanketed Central Java, and economic losses totaled approximately USD 600 million. The event was scientifically significant because Merapi shifted from its typical dome-collapse behavior to explosive column-generating eruptions.
Why is Merapi so dangerous?
Merapi is considered one of Earth's most dangerous volcanoes due to the convergence of three factors: extreme eruption frequency (106 eruptions recorded, roughly one every 4–5 years), a lethal eruption style that produces fast-moving pyroclastic flows reaching 60–100+ km/h, and an enormous exposed population of approximately 1.3 million within the hazard zones plus 3.7 million in greater Yogyakarta. The volcano's dome-collapse pyroclastic flows can reach communities 5–15 km away within minutes, and secondary lahars threaten downstream areas for months after eruptions. The steep flanks channel flows directly toward densely populated lowlands, and evacuation logistics are complicated by poor road infrastructure and the cultural attachment of communities to their volcanic-soil farmland.
What is a juru kunci?
A juru kunci (literally 'key keeper') is a hereditary spiritual guardian appointed by the Yogyakarta Sultanate to serve as an intermediary between the human world and the supernatural forces believed to inhabit Mount Merapi. The juru kunci lives near the summit, performs regular rituals and offerings, and is traditionally consulted before major decisions regarding the volcano. The most famous juru kunci was Mbah Maridjan, who held the position for decades and became nationally known when he refused to evacuate during the 2006 eruption. He was killed during the 2010 eruption at his post. The tradition reflects the deep integration of Javanese spiritual beliefs with the physical reality of living on an active volcano.
How does Merapi compare to other Indonesian volcanoes?
Merapi is the most frequently erupting volcano in Indonesia, with 106 recorded eruptions — significantly more than Semeru (70+), Krakatau (40+), or Kelud (35+). However, Merapi's individual eruptions are typically smaller in magnitude (mostly VEI 1–3, occasionally VEI 4) compared with the catastrophic VEI 6–7 events produced by Krakatau (1883) and Tambora (1815). What makes Merapi exceptionally dangerous is the combination of relentless frequency, proximity to millions of people, and the speed of its pyroclastic flows. In terms of cumulative fatalities since the sixteenth century (2,600+), Merapi ranks among Indonesia's deadliest, though single events at Krakatau (36,000+) and Tambora (92,000) far exceed any individual Merapi eruption.