Satellite thermal anomalies occurred at or near Langila on three different days in early 2007 (BGVN 32:02). Although erupting regularly, only one other anomaly (on 2 April 2007) was detected after that time through 6 March 2008. Langila is noted for its ongoing fluctuating eruptions and occasional ash clouds that rise to more than 5 km altitude and pose a threat to aviation. Throughout this reporting period, April 2007 to January 2008, ash emissions were usually accompanied by weak to moderately loud roaring.

During May 2007, the Rabaul Volcanic Observatory (RVO) reported the emission of ash clouds from Langila's Crater 2. Ash plumes rose to an altitude of 3.3-4.3 km and drifted NW. Weak roaring noises were heard on 11-12 May and a weak glow was visible on 7-8, 11-12, and 15 May. Weak roaring noises were again heard on 20 May, and an increased phase of eruptive activity that began on 22 May continued until end of the month. The increased activity was characterized by forceful emission of thick pale-gray to dark gray-brown ash clouds from 22-27 May. The emission changed to subcontinuous thick dark gray-brown ash clouds on 28-29 May before changing back to occasional thick, pale-gray clouds on 30-31 May. Two large explosions on 30 May accompanied the ash emission. The ash clouds from these two explosions rose 4 km above the summit before being blown NW. On the other days, the ash clouds rose 2-3 km above the summit before drifting NW of the volcano. Continuous fine ashfall occurred at Kilenge Catholic Mission (~10 km NW) and surrounding areas during 22-31 May. The ash emissions were accompanied by occasional weak to loud roaring noises from the 22 to 28 May before turning subcontinuous during 29-31 May. On 30 May two large explosions produced ash plumes that rose to ~5.3 km and drifted NW. A weak glow was visible on 7-8, 11-12, 15, and 20 May and again on 29 and 31 May. Incandescence was visible on 29 May. On 26 May, the seismograph deployed at Kilenge became operational.

During June RVO reported a slight decrease in eruptive activity that began on 22 May, however, the emissions of ash plumes from Crater 2 were occasionally forceful. The emissions were continuous on 6, 7, and 10 June and accompanied by roaring noises; booming noises were heard on 1 and 10 June. Ash plumes rose to ~ 2.3-4.3 km and drifted NNW. Based on observations of satellite imagery and information from RVO, the Darwin VAAC reported that on 3 June, an ash plume rose to an altitude of 3 km and drifted W. Ashfall was again reported at Kilenge Catholic Mission and surrounding areas. Seismic activity in June was at a high level, dominated by continuous tremor and occasional explosion signals. During the latter part of the month, seismic activity decreased to a low-moderate level. It was dominated by continuous irregular tremors and occasional harmonic tremors. Low-frequency earthquakes ranged from 1 to 7 events per day.

During July 2007, eruptive activity continued at a low level but included thin-to-thick, pale-gray ash clouds. Weak roaring noises were heard on 1 July, but glow was absent at night. On 2 July ash clouds were ejected forcefully and rose ~2 km, drifted NW, and resulted in a fine ashfall downwind. On 6-7, and 9-13 July, ash clouds rose less than 1 km above the summit before drifting NNW. Except for 1 July when weak roaring noises were heard, the volcano was quiet and without appreciable night glow. Seismicity registered at low-moderate levels, dominated by non-harmonic and harmonic tremor of continuous, irregular, or banded character. During July, the daily number of low-frequency earthquakes ranged between 1 and 12 events per day. The one high-frequency earthquake occurred on 27 July.

RVO reports noted mild but continuous ash and white vapor plumes from Crater 2 during 1 August-30 September. Ash plumes generally rose to altitudes of ~1.8-3.3 km and drifted WNW. On 8 August, a large explosion produced an ash plume that rose to an altitude of 5.3 km and drifted SW. Ashfall was reported downwind. Incandescent fragments were ejected from the summit on 21-22 September.

During 1-7 October 2007, RVO reported low-to-moderate eruptive activity consisting of continuous emission of pale gray ash clouds which rose to ~1.8-3.3 km and were blown W to NW. During the second week, the white vapor accompanied by pale gray ash clouds continued; these rose less than 1 km before being blown to the NW of the volcano. On 19, 16, and 27 October, the ash clouds rose less than 2 km before being blown WNW. Consistently, the ash emissions were accompanied by occasional weak-to-loud roaring or booming noises. On most occasions, there was no glow observed at night, however, a weak-to-bright glow accompanied by projection of incandescent lava fragments was visible on 12 and 22 October. Crater 3 remained quiet. Seismic activity was at low-to- moderate level dominated by low frequency earthquakes and bands of harmonic and non-harmonic tremors. The daily number of low-frequency earthquakes ranged from 2-15. Less than 10 high-frequency events were recorded during October.

In January 2008, activity generally remained low. Some ash fell on 6-7, and 9 January with fluctuating glow visible. On 10, 13, and 25 January the incandescent glow was bright. More direct observations through late February 2008 by RVO staff and affiliates confirmed ongoing eruptions. During February, Crater 2 continued to erupt. Most days, these eruptions generated ash plumes typically rising a few hundred meters. Observers noted incandescent glow or noises on 7, 9, 11, and 21-23 February.

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: Herman Patia, Rabaul Volcano Observatory (RVO), PO Box 386, Rabaul, Papua New Guinea; 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/); Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/).