Volcanos

Roundup of Global Volcanic Activity - New Activity for the week 7 December - 13 December 2022

Ahyi - Mariana Islands (USA) : Unrest continued to be detected at Ahyi Seamount during 7-13 December. Wake Island hydrophone sensors detected daily signals consistent with explosions during 10-12 December. No signs of underwater plumes were visible in satellite images during 10-11 December; weather clouds obscured the area on 12 December.

Fuego - South-Central Guatemala : INSIVUMEH reported that the eruption at Fuego was ongoing during 7-13 December, though activity had notably intensified during 10-11 December. The seismic network recorded 4-10 explosions per hour during the week, with ash plumes rising as high as 1.2 km above the crater rim. The ash plumes generally drifted 10-20 km NW, W, and SW, causing daily ashfall in areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Finca Palo Verde, Sangre de Cristo (8 km WSW), San Pedro Yepocapa (8 km NW). Daily shock waves rattled structures in communities around the volcano. Daily block avalanches descended the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Honda, Las Lajas (SE), and El Jute (ESE) drainages, often reaching vegetated areas. Strombolian explosions ejected incandescent material as high as 200 m above the summit on a few of the days. Activity increased on 10 December. In a special report posted at 2241, INSIVUMEH noted that in the previous minutes multiple explosions of variable intensities produced ash plume that rose 1.2 km above the summit and drifted 30 km W and NW. Pulsating lava fountains rose as high as 500 m above the summit. A lava flow had traveled 800 m down the Ceniza drainage by the time the report was issued, and avalanches of material spalled from its front reached vegetated areas. At 2300 pyroclastic flows descended the Las Lajas drainage several kilometers. Dense ash plumes and pyroclastic flows down the Las Lajas drainage continued for at least an hour. Just before 0030 on 11 December pyroclastic flows traveled several kilometers down the Ceniza drainage on the SW flank. Lava fountains rose as high as 300 m. By 0640 dense ash plumes were rising over 1.2 km above the summit and the lava flow remained active. Avalanches of material from the advancing lava front descended to vegetated areas. Satellite images showed that ash clouds had spread NE, E, and SE, covering a wide area in the department of Sacatepéquez and the central and southern parts of the department of Guatemala. Activity decreased by the early afternoon; lava fountaining, dense ash emissions, and pyroclastic flows had all ceased before 1410.

Lascar - Northern Chile : SERNAGEOMIN reported that an eruption at Láscar began at 1236 on 10 December with an explosive event that produced a dense ash plume and pyroclastic flows proximal to the crater. Hikers were near the crater and took video of the eruption. According to SEGEMAR the pyroclastic flows traveled short distances to the N and SE. The ash plume rose about 6 km above the crater rim and drifted SW. The event was coincident with a long-period earthquake detected by the seismic network. CKELAR noted that the thermal anomaly had intensified during the five days prior to the eruption along with increased sulfur dioxide gas emissions.

Mauna Loa - Hawaiian Islands (USA) : HVO reported that activity at Mauna Loa’s Fissure 3 declined during 7-9 December and then ceased on 10 December. The main lava flow had only advanced a small distance during 6-7 December, at a rate of about 6 m per hour, possibly due to a significant breakout that had occurred about 4.5 km upslope of the flow front. Lava erupting from Fissure 3 was greatly reduced by the morning of 8 December. Lava overtopped channels near the vent but had not advanced farther than 4.4 km from the vent by 0930. The channel at lower elevations appeared to be drained and was likely no longer feeding the main flow which had stalled about 2.8 km from the Daniel K. Inouye Highway (Saddle Road). The sulfur dioxide emission rate had declined to 30,000 tonnes per day. By 1130 on 9 December low lava fountains at Fissure 3 fed flows that traveled as far as 2.65 km NE. By 0700 on 10 December a lava pond in the Fissure 3 vent was visible and fed short lava flows that stagnated at 2.6 km. Tremor levels were slowly declining and the sulfur dioxide emission rate was about 2,000 tonnnes per day. Lava was confined to the small pond by 1435 and gas emissions had significantly declined. No activity was visible on the flow field overnight during 10-11 December, and by 0700 on 11 December the Fissure 3 vent was barely incandescent. Scientists observed no lava movement and only minor incandescence at the vent during an overflight in the early morning of 12 December. They heard a small explosion that accompanied a spray of spatter from the W end of the fissure.

Semeru - Eastern Java : BNPB reported that residents continued to be impacted by the collapses and large pyroclastic flows on Semeru’s SE flank on 4 December. As of 6 December, there were 781 people spread across 21 evacuation shelters and heavy ashfall prevented aid from easily reaching Pronojiwo Village, according to BNPB. Kajar Kuning was the worst affected village. PVMBG reported that lava continued to erupt from the summit vent during 4-9 December, though activity generally declined. Ongoing thermal anomalies were identified in satellite images, though the intensity had decreased. The rate of deformation had declined based on tiltmeter data. Four pyroclastic flows moved as far as 6 km down the SE flanks, and avalanches of material traveled 300-500 m SE. At 0521 on 8 December a gray-to-white ash plume rose around 300 m above the summit and drifted N. At 0536 a gray ash plume rose 400 m and drifted N, as reported by a ground-based observer. A dense gray ash plume rose 500 m and drifted N at 0521 on 9 December. Eruptive activity continued during 10-13 December. At 0653 on 10 December a dense white-to-gray ash plume rose about 700 m above the summit and drifted N. White-and-gray ash plume were visible at 0652 on 11 December and 0727 on 12 December rising at least 500 m and drifting S and SW, respectively.