Report on Lewotobi (Indonesia) — 2 July-8 July 2025
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 2 July-8 July 2025
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2025. Report on Lewotobi (Indonesia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 2 July-8 July 2025. Smithsonian Institution and US Geological Survey.
Lewotobi
Indonesia
8.542°S, 122.775°E; summit elev. 1703 m
All times are local (unless otherwise noted)
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that an explosive eruption from Lewotobi Laki-laki at 1105 on 7 July was accompanied by loud booming sounds. A dense gray-to-black ash plume rose to around 18 km above the summit and drifted NE, N. and NW. Photos of the eruption showed pyroclastic flows descending the N and NE flanks as far as 5 km. The eruption lasted about six and a half minutes based on seismic data. According to the Badan Nacional Penanggulangan Bencana (BNPB) ashfall was reported in several villages in the Wulanggitang District including Nawakote, Klatanlo, Hokeng Jaya, Boru, and Pululera. A smaller explosion at 1519 generated a dense gray ash plume that rose around 1 km above the summit and drifted W. Another significant event at 1932 produced a dense gray-to-black ash plume that rose about 13 km above the summit and drifted W and NW. Incandescent material descending multiple flanks was visible in a webcam image starting at 1944.
News outlets reported that some flights from the El Tari Kupang Airport to Frans Seda Maumere Airport, along with a few dozen international flights, were cancelled. The Komodo International Airport, around 300 km W, was closed during 7-8 July. The Alert Level remained at 4 (on a scale of 1-4) and on 25 June the exclusion zone was reduced to 6 km from the center of Laki-laki and 7 km in a semicircle clockwise from the SW to the NE.
Geological Summary. The Lewotobi edifice in eastern Flores Island is composed of the two adjacent Lewotobi Laki-laki and Lewotobi Perempuan stratovolcanoes (the "husband and wife"). Their summits are less than 2 km apart along a NW-SE line. The conical Laki-laki to the NW has been frequently active during the 19th and 20th centuries, while the taller and broader Perempuan has had observed eruptions in 1921 and 1935. Small lava domes have grown during the 20th century in both of the summit craters, which are open to the north. A prominent cone, Iliwokar, occurs on the E flank of Perampuan.
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Badan Nacional Penanggulangan Bencana (BNPB), Antara News, Antara News, Antara News, Antara News