Alert Level 4 raised for Lewotobi Laki-laki volcano, Indonesia

The Center for Volcanology and Geological Hazard Mitigation (CVGHM) raised the Alert Level for Mount Lewotobi Laki-laki from Level III to Level IV at 03:00 LT on February 12 (19:00 UTC on February 12).

The volcano exhibited increased activity between January 3 and February 13, with a notable surge in seismic activity.

Observations reported white and gray summit emissions, ranging from 50 to 1 500 m (164 to 4 921 feet) in height, with fluctuating intensity. The weather varied from clear to rainy, with winds blowing in multiple directions.

Eruptions were recorded with ash columns reaching 500 to 800 m (1 640 to 2 600 feet) above the summit.

The presence of faint firelight near the summit suggests that magma is reaching the surface, with a red glow visible at night.

The number of harmonic earthquakes has risen indicating increased fluid movement and gas release within the fractures. The rise in low-frequency earthquakes suggests that magma is traveling toward the surface.

Visual assessments noted solfatara emissions along a crack on the northwest side of the peak, forming thin to thick plumes. The emissions point to a weak zone which could lead to a directed blast, an eruption concentrated in a specific direction, mainly toward the northwest and northeast.

Previous eruptions have deposited volcanic material on the slopes, posing a lahar risk in the event of heavy rains. Communities near Dulipali, Padang Pasir, Nobo, Klatanlo, Hokeng Jaya, Boru, and Nawakote are at increased risk.

A surge in volcanic earthquakes was recorded from 22:00 LT (14:00 UTC) on February 11 through February 13, suggesting ongoing magma supply, increasing the likelihood of further eruptive events.

Authorities have advised against any activities within a 6 km (3.7 miles) radius of the eruption center because of the increased threat. Residents and visitors should avoid the southwest-northeast sector up to 7 km (4.3 miles) from the summit.

The local government has urged people to remain calm and follow official directives while avoiding misinformation.

Ashfall is expected in surrounding areas, prompting officials to recommend wearing protective masks to prevent respiratory issues.

The Lewotobi Laki-laki Observation Post in Pululera Village continues to monitor the situation closely in coordination with the Center for Volcanology and Geological Disaster Mitigation (PVMBG) and regional disaster response teams.

Mount Lewotobi Laki-laki is part of the Lewotobi volcanic complex, consisting of twin stratovolcanoes, Lewotobi Laki-laki and Lewotobi Perempuan, located on Flores Island in East Nusa Tenggara. The two summits, separated by less than 2 km (1.2 miles), are aligned in a northwest-southeast orientation.

Lewotobi Laki-laki, the more frequently active of the two, has experienced multiple eruptions throughout recorded history, with notable activity in the 19^th and 20^th centuries.

The volcano’s eruptions have ranged from mild to moderate in intensity, with a Volcanic Explosivity Index (VEI) of 2 to 3. Historical records indicate eruptive events in 1932, 1869, and 1675, demonstrating the volcano’s capability of producing both explosive eruptions and lava dome growth.

Small lava domes have formed within its summit crater over the last century, contributing to the evolving landscape of the edifice. Situated within the Sunda Volcanic Arc, Lewotobi Laki-laki’s activity is driven by subduction processes along the convergent boundary between the Indo-Australian and Eurasian tectonic plates.

References:

¹ Kenaikan Tingkat Aktivitas dari Level III (Siaga) ke Level IV (AWAS) Gunung Lewotobi Laki-laki, Nusa Tenggara Timur Tanggal 13 Februari Pukul 03.00 WITA – PVMBG – February 13, 2025

² Lewotobi – GVP – Accessed on February 13, 2025

³ Lewotobi Laki-laki 20250211/1931Z – MAGMA Indonesia – February 11, 2025