Langila, located at the western tip of Papua New Guinea’s New Britain Island, consists of a group of four small overlapping cones. Frequent mild-to-moderate explosive eruptions with ash emissions have been recorded since the 19th century from three active summit craters. The current eruption period began in October 2015 and has recently been characterized by low-level thermal activity and ash plumes (BGVN 45:11). Similar activity continued during this reporting period of November 2020 through April 2021 using information primarily from the Darwin Volcanic Ash Advisory Center (VAAC) and satellite images.

The NASA Global Sulfur Dioxide page, using data from the TROPOMI instrument on the Sentinel-5P satellite, showed a few weak sulfur dioxide plumes during early December 2020 and late March 2021 that drifted in different directions (figure 22). The Darwin VAAC issued notices of ash plumes on 9 January 2021 to 4.9 km altitude that drifted W, on 13 January to 3 km that drifted WSW, and on 5 April to 1.5 km that drifted SW.

Figure 22. Small sulfur dioxide plumes were visible above Langila based on data from the TROPOMI instrument on the Sentinel-5P satellite. Faint plumes drifted W on 8 December (top left) 2020, N on 10 December (top right), SE on 18 March (bottom left) 2021, and NW on 20 March (bottom right). Small plumes were also present on most of those days originating from Manam (to the W) and Bagana (to the E) volcanoes. Courtesy of the NASA Global Sulfur Dioxide Monitoring Page.

MIROVA recorded a single low-power thermal anomaly was detected during early November, followed by four more during early December (figure 23). A low-power cluster of thermal anomalies resumed in mid-March that continued through the month. Three more anomalies were recorded in late April. The latter part of this thermal activity was also detected in Sentinel-2 infrared satellite imagery. A single thermal anomaly was visible at the summit crater beginning in February 2021, and in March a second thermal anomaly appeared that continued to be observed through April (figure 24).

Figure 23. Few low-power thermal anomalies at Langila were detected during early November (1) and early-to-mid-December (4) 2020 as recorded by the MIROVA graph (Log Radiative Power). A cluster of low-power thermal anomalies were detected in mid-March 2021 that continued through the month, followed by three anomalies in late April. Courtesy of MIROVA.

Figure 24. Weak thermal anomalies were visible at the summit of Langila in infrared satellite imagery during February through April 2021. Though clouds obscured most of the view on 12 February (top left), a single faint thermal anomaly was observed. On 9 March (top right) two thermal anomalies were observed at the summit, which were also visible on 6 (bottom left) and 18 (bottom right) April. On 18 April, the western thermal anomaly seemed to have decreased in strength slightly. Sentinel-2 satellite images with “Atmospheric penetration” (bands 12, 11, 8A) rendering. Courtesy of Sentinel Hub Playground.

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: Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); NASA Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center (NASA/GSFC), 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).