The Darwin VAAC issued an activity report stating that the Rabaul Volcano Observatory (RVO) had noted elevated activity since 24 April 2005. Between 28 April 2005 and 4 May 2005 Langila emitted more ash than normal, and the International Federation of Red Cross And Red Crescent Societies (IFRC) determined that ~ 3,490 people had been affected by the eruption when ashfall damaged small food gardens and contaminated some water sources.

VAAC reports on 4 May and 6-7 May noted thin plumes extending NW 110 km and 75 km, respectively. Later, on 7-8 May, the identifiable plume was half as long and diminishing. Plumes and other diagnostics eventually became obscured by weather clouds. On 8 June analysts at the Darwin VAAC saw a low-altitude plume and a hot spot. The plume moved westward and remained visible into 9 June when it ceased being detectible.

During 13-19 June 2005, Langila's Crater 2 continued to erupt. At times the eruption was marked by moderate to strong emissions of thick gray-brown ash clouds occurring at irregular intervals. Ash clouds from the eruption rose variably to 700-1000 m before they were blown to the W and NW. At other times weak to moderate emissions of light gray ash clouds were observed. Considerable ash fell near the volcano and extended to the W and NW, between Warimo and Aimola. Crater 3 was quiet. Low and high frequency earthquakes and volcanic tremor were recorded.

The Darwin VAAC reported a Langila plume on 13 June to 3-4 km altitude, but cloud cover later obscured the plume. Another plume became visible on imagery on 16 June moving W at 30 km/hour at an estimated altitude of ~ 3 km; ongoing plumes became hard to see about mid-day on 17 June. Several other episodes of plume image detection were seen. One was identified by the VAAC on 21 June, with an observation of altitude to ~ 3 km and plume length reaching 300 km to the NW. The evidence of eruption only continued until the next day, when cloud cover obscured the area. A further, brief episode of plume detection occurred beginning early on 25 June but detection ended before noon. On 30 June, the Darwin VAAC repeated a US Air Force Weather Agency (AFWA) report on a Langila plume seen on imagery, blowing SW at 20 km/hr and reaching ~ 3 km altitude. By about 6 hours later that plume ceased to be visible.

Moderate levels of volcanic activity occurred at Langila's Crater 2 during 15-21 August. The activity was marked by occasional sub-continuous forceful emissions of ash clouds. The ash clouds rose as high as 1 km before drifting N and NW. Fine ash fell in villages along the coast. On the evening of 18 August projections of incandescent lava fragments were seen. Based on a pilot report, the Darwin VAAC reported that ash from Langila was visible in the vicinity of the volcano on 23 August, at 3-4.6 km altitude. A plume was seen a bit later on MODIS imagery extending 110 km to the NNW but ash was not visible in satellite imagery.

Geological Summary. Langila, one of the most active volcanoes of New Britain, consists of a group of four small overlapping composite basaltic-andesitic cones on the lower E flank of the extinct Talawe volcano in the Cape Gloucester area of NW New Britain. A rectangular, 2.5-km-long crater is breached widely to the SE; Langila was constructed NE of the breached crater of Talawe. An extensive lava field reaches the coast on the N and NE sides of Langila. Frequent mild-to-moderate explosive eruptions, sometimes accompanied by lava flows, have been recorded since the 19th century from three active craters at the summit. The youngest and smallest crater (no. 3 crater) was formed in 1960 and has a diameter of 150 m.

Information Contacts: Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea; International Federation of Red Cross And Red Crescent Societies (IFRC) (URL: https://reliefweb.int/); U.S. Air Force Weather Agency (AFWA)/XOGM, Offutt Air Force Base, NE 68113, USA; Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, Northern Territory 0811, Australia (URL: http://www.bom.gov.au/info/vaac/).