Based on visual observations, CVGHM lowered the Alert Level for Batu Tara to 1 (on a scale of 1-4) on 9 October. In March 2007, ash plumes rose to a maximum altitude of 4.3 km (14,000 ft) a.s.l. During 3 September-9 October, plumes rose to an altitude of approximately 1.4 km (4,600 ft) a.s.l.

Based on observations of satellite imagery, the Darwin VAAC reported that an ash plume rose to an altitude of 3 km (10,000 ft) a.s.l. on 13 October and drifted N and W.

Geological Summary. The small isolated island of Batu Tara in the Flores Sea about 50 km N of Lembata (fomerly Lomblen) Island contains a scarp on the eastern side similar to the Sciara del Fuoco of Italy's Stromboli volcano. Vegetation covers the flanks to within 50 m of the summit. Batu Tara lies north of the main volcanic arc and is noted for its potassic leucite-bearing basanitic and tephritic rocks. The first historical eruption, during 1847-52, produced explosions and a lava flow.

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