Indonesia’s Batu Tara volcano continues to spill ash into the air through late September, 2013. According to Volcano Discovery, relatively frequent larger strombolian to vulcanian explosions continued to produce ash plumes reaching altitudes of about 7,000 feet (2.1 km). Such plumes have been a near-daily occurrence since the beginning of the month.
Strombolian eruptions are defined by distinct bursts of expulsion of fluid lava from the mouth of a magma-filled conduit at the summit. The explosions can be repeated every few minutes, and the explosions can send lava to hundreds of meters. Such eruptions are caused by the bursting of large bubbles of gas trapped in the lava as it they reach the surface. Vulcanian eruptions are short, violent and usually relatively small explosions of magma, and results from the fragmentation and explosion of a plug of lava within a volcanic conduit, or the rupture of lava that piles up over a vent (a lava dome).
Batu Tara sits in the Flores Sea, only about 30 miles (50 km) north of Lembata Island, in the Lesser Sunda Islands, Indonesia. This relatively small volcano, which appears as an island itself, sits on the top of a larger stratovolcano with a base that reaches over 3,000 meters (9842 feet) below sea level. It has been relatively quiet in historic times, until it began erupting in July of 2006. It has been erupting frequently at low levels since that time.
The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite captured this true-color image of the ash plume from Batu Tara on September 29 as it passed over the region.