PVMBG reported a small eruption at Sangeang Api at 1154 on 15 July characterized by Strombolian activity, and an ash plume that rose 100-200 m above the crater rim and drifted SW. Prior to the event, thermal anomalies had increased beginning in March, and seismicity had increased starting in April.

Based on analyses of satellite imagery, PVMBG observations, and wind data, the Darwin VAAC reported that on 16 July an ash plume rose to an altitude of 2.1 km (7,000 ft) a.s.l., or 200 m above the crater rim, and drifted NW.

Geological Summary. Sangeang Api volcano, one of the most active in the Lesser Sunda Islands, forms a small 13-km-wide island off the NE coast of Sumbawa Island. Two large trachybasaltic-to-tranchyandesitic volcanic cones, Doro Api and Doro Mantoi, were constructed in the center and on the eastern rim, respectively, of an older, largely obscured caldera. Flank vents occur on the south side of Doro Mantoi and near the northern coast. Intermittent eruptions have been recorded since 1512, most of them during in the 20th century.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)