The Lewotobi volcano in Indonesia erupted with tremendous force and sent a massive ash cloud 11 kilometers (6.8 miles) into the sky. The eruption started Tuesday and created a mushroom-shaped ash cloud that people could see from 150 kilometers (93 miles) away. The volcano continued to erupt through Wednesday afternoon, with ash reaching heights of 5,000 meters (16,400 feet).
Local authorities raised the alert to its highest level and widened the danger zone. They urged residents to evacuate from areas within an 8-kilometer (5-mile) radius of the crater. Mount Lewotobi Laki-Laki in East Nusa Tenggara province poses a serious risk of lava flows, especially if heavy rainfall occurs. The ash cloud’s spread across Indonesian airspace now threatens local communities, regional infrastructure and air traffic. This eruption shows how Indonesia’s volcanic systems remain unpredictable and powerful, requiring constant monitoring and quick response measures.
Geological Structure of Lewotobi Volcano Complex
The Lewotobi volcano rises as a unique twin volcano system in southeastern Flores Island, Indonesia. This remarkable formation differs from typical single-vent volcanoes. Two adjacent stratovolcanoes make up Lewotobi – Lewotobi Laki-laki (“male”) and Lewotobi Perempuan (“female”), which locals view as a “husband-wife” pair. These peaks emerged through layers of lava, ash and volcanic debris.
These volcanic twins stand less than 2 kilometers apart on a northwest-southeast line. A natural saddle at 1,232 meters connects these majestic peaks. The northwestern peak, Lewotobi Laki-laki, reaches 1,584 meters, while its partner Lewotobi Perempuan towers higher at 1,703 meters. Each volcano shows its own unique traits and eruption patterns.
Both volcanoes’ summit craters face north. Laki-laki’s crater spans about 400 meters across, while Perempuan’s crater is substantially larger at 700 meters in diameter. Small lava domes developed within both summit craters during the 20th century.
The Lewotobi volcanic complex belongs to the Lesser Sunda Islands volcanic arc. The subduction of the Indo-Australian Plate beneath the Eurasian Plate created this formation. This process generates the right conditions for magma formation deep under the volcano.
Lewotobi’s composition is mostly andesitic and has basaltic andesite. These elements make the volcano explosive by nature. The region beneath Lewotobi contains continental crust, and earthquakes occur up to 50 kilometers deep. Magma travels upward through the Benioff melting zone at depths between 110-200 kilometers.
The geological makeup shapes eruption patterns uniquely. Laki-laki shows nowhere near the same activity level as its partner. Historical records show frequent eruptions from Laki-laki throughout the 19th and 20th centuries, while Perempuan erupted only twice – in 1921 and 1935.
Eruption Timeline and Ash Cloud Events (2023–2025)
Lewotobi Laki-laki’s activity started on December 23, 2023, with an explosive eruption that lasted 24 minutes. The original event created dense gray ash plumes that rose 1-1.5 kilometers above the summit. The northwest peak showed a crack that released thick white smoke about 300 meters high. The eruption forced approximately 6,500 people to leave their homes by January 2024.
The volcano’s activity reached a devastating peak on November 4, 2024. Nine people lost their lives and many homes were destroyed in this catastrophic eruption. The volcano erupted multiple times on November 8, sending one ash plume soaring 10 kilometers high. Continuous eruptions the next day made authorities evacuate about 16,000 people from nearby villages.
Another powerful eruption happened in March 2025. The volcano sent ash clouds more than 8 kilometers into the sky. Officials raised the alert level to its highest point, which disrupted flights to Bali.
A massive eruption shook the region on June 17, 2025, at 17:35 local time. The volcano shot an enormous ash column 11 kilometers (6.8 miles) high into the air. People could see this spectacular mushroom-shaped cloud from 90-150 kilometers away. Deep volcanic earthquakes had jumped from 8-10 daily events to 50 events in just two hours before this eruption.
The next day brought another eruption with a smaller ash cloud reaching 1 kilometer high. People from several villages including Boru, Hewa and Watobuku had to evacuate quickly. The eruptions caused dozens of canceled flights to and from Bali, which affected routes from Australia, India, Singapore and other locations.
Records show Lewotobi has erupted at least 23 times since 1675, averaging one eruption every 15.2 years. The frequency has increased significantly over the last several years, with one eruption happening every 5.5 years since 1900.
Impact on Airspace, Infrastructure and Population
A massive ash cloud from Lewotobi volcano has created chaos in air travel throughout Indonesia and nearby countries. Bali’s I Gusti Ngurah Rai International Airport reported 87 flight disruptions, with 66 international and 21 domestic cancelations right after the June 17 eruption. These disruptions hit major routes that connect Bali to Adelaide, Auckland, Brisbane, New Delhi, Darwin, Kuala Lumpur, Melbourne, Perth, Pudong, Singapore, Sydney and Ho Chi Minh City.
Major carriers had to stop their services, especially when dealing with Australian routes. Virgin Australia stopped its flights between Brisbane, Melbourne and Bali. Jetstar canceled four flights from Australia, while Air New Zealand stopped two flights between Bali and Auckland. The disruption also affected Air India, Singapore’s TigerAir, China’s Juneyao Airlines and Qantas.
The eruption’s impact reached beyond Bali and forced several regional airports to close. Fransiskus Xaverius Seda airport in Maumere stayed closed until June 19 because of ash concerns. A tour operator reported that more than 1,000 tourists faced problems, mainly those heading to Bali and Komodo National Park.
The situation forced thousands of residents to leave their homes near the volcano. The National Disaster Management Agency had counted 4,838 evacuees after the November 2024 eruption. The June 2025 event pushed residents from Nurabelen village to seek shelter in Konga and Nileknoheng villages. Ash covered many settlements outside the exclusion zone, including Boru, Hewa and Watobuku.
The damage to infrastructure has been heavy. The November 2024 eruption destroyed seven schools, almost two dozen houses and a convent. The ash was so thick that staff at the Volcano Observation Post in Pululera had to move to a nearby church.
Officials extended the danger zone to 8 kilometers from the crater. They warned about possible lahar floods—dangerous flows of volcanic mud or debris—if heavy rain falls. Continuous tremors after the main eruption showed that the volcano remained active.
Appreciate Lewotobi Volcano
Lewotobi volcano ranks among Indonesia’s most active and unpredictable natural hazards, as its recent devastating eruption showed. The ash cloud stretched 11 kilometers high, adding another chapter to its volcanic history that dates back to 1675. This twin volcano’s unique “husband-wife” setup poses the most important threats to nearby communities and local infrastructure.
The eruption frequency has picked up speed alarmingly over the last several years. While historical records show one eruption every 15.2 years on average, Lewotobi now erupts every 5.5 years since 1900. The June 2025 eruption definitely confirms this worrying pattern.
The impact reaches way beyond the immediate danger zone. Ash fallout threatens crops and water supplies while thousands of residents remain displaced. Airlines canceled 87 flights from multiple international carriers. This left tourists stranded and disrupted travel plans throughout Southeast Asia and Australia.
Scientists found strong evidence that the volcano stays highly active. Deep volcanic earthquakes spiked before the latest eruption – jumping from 8-10 daily events to 50 events in just two hours. The data and Lewotobi’s complex position within the Lesser Sunda Islands volcanic arc point to possible future eruptions.
Indonesian authorities took swift action by expanding the danger zone to an 8-kilometer radius and evacuating residents. Heavy rainfall could trigger dangerous lahar flows, which remains a serious concern for communities in the region.
Lewotobi reminds us powerfully of nature’s raw force and the volcanic risks that exist across Indonesia’s archipelago. Though monitoring systems help predict activity, this twin volcano system’s unpredictable nature just needs constant alertness from authorities and locals alike.
FAQs
Q1. When did the most recent significant eruption of Mount Lewotobi occur?
The most recent significant eruption of Mount Lewotobi occurred on June 17, 2025, when it expelled an enormous ash column approximately 11 kilometers (6.8 miles) high. This eruption was followed by subsequent activity on June 18, 2025.
Q2. How has the eruption frequency of Lewotobi changed over time?
The eruption frequency of Lewotobi has increased significantly. Historically, it averaged one eruption every 15.2 years since 1675. However, since 1900, the frequency has increased to one eruption approximately every 5.5 years.
Q3. What are the main dangers associated with Lewotobi’s eruptions?
The main dangers include ash clouds affecting air travel, lava flows, pyroclastic flows and potential lahar floods (hazardous flows of volcanic mud or debris) during heavy rainfall. The eruptions also pose risks to nearby communities, often necessitating evacuations.
Q4. How has the recent Lewotobi eruption impacted air travel?
The eruption has severely disrupted air travel across Indonesia and neighboring regions. Numerous flights were canceled, particularly those servicing Australian routes. Major airports, including Bali’s I Gusti Ngurah Rai International Airport, reported significant flight disruptions affecting both domestic and international travel.
Q5. What measures have been taken to protect the local population from the volcano’s activity?
Authorities have expanded the danger zone to an 8-kilometer radius from the crater and implemented evacuation protocols for nearby villages. They have also raised the alert to its highest level and are continuously monitoring the volcano’s activity to provide timely warnings to the local population.
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