Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 10 January - 16 January 2018

Kadovar | Papua New Guinea : According to Brandon Buser, just after eruption plumes started rising from a vent on the SE side of Kadovar on 5 January boats from a village on the mainland (22 km SW) and from Bam (25 km E) were sent to the island to evacuate residents. The entire population of the island (about 500 people according to a news article citing the Red Cross) was evacuated by the boats and numerous canoes to Blup Blup (15 km N). Activity escalated around midnight. The next day, at a distance of 65 km, Buser and others saw ash emissions rising from Kadovar, and at about 24 km away from the island they experienced ashfall. As they were circling the island a large event sent a large plume hundreds of feet into the air and ejected large boulders into the ocean. During another visit on 8 January Buser noted two new eruptive vents, ashfall covering everything on the village side, and wet falling ash. RVO reported that activity significantly escalated on 12 January characterized by a large blast of a substantial amount of material and “big” glowing red rocks directed to the S; the report noted that the blast was the only one reported to date. Observers on Blup Blup saw incandescence emanating from either the summit or an area out of view on the S flank. Large amounts of sulfur dioxide had been detected since 8 January, and continued to be emitted. A fracture had previously been reported on 6 January extending from the summit to the coast. When seen on 12 January, the fracture was wider and vigorous steaming was occurring at sea level. Ash plumes drifted tens of kilometers W and NW. RVO noted that the displaced villagers were getting transferred to the mainland, along with islanders from Bam, due to the relatively close proximity to the eruption plus the logistics of supplying them. Five newly-named vents were observed during an overflight conducted on 13 January: Main Crater, Western vent, and Southern vent (all three are at the summit), the SE Coastal vent, and the Southern Coastal vent. Sometimes voluminous steam and dense gray plumes rose 1 km above the Main Crater. The emissions obscured views of Southern and Western vents. The SE Coastal Vent was very active, emitting dense white steam plumes 600 m a.s.l. A possible lava dome was at the base of the plumes but showed no evidence of incandescence. The Southern Coastal Vent, located where the original fractures entered the sea, was inactive.

Mayon | Luzon (Philippines) : PHIVOLCS reported that a phreatic eruption at Mayon was detected at 1621 on 13 January, generating an ash plume that rose 2.5 km and drifted SW. The seismic network recorded the event for 1 hour and 47 minutes. Trace amounts of ash fell in Barangays Anoling (4 km S), Sua (6 km SSW), Quirangay (6 km SSW), Tumpa (7 km SW), Ilawod (10 km SSW), and Salugan (9 km SSW) of Camalig, and in Barangays Tandarora (10 km SW), Maninila (18 km S), and Travesia (10 km SW) in Guinobatan. A sulfur odor was noted by residents of Camalig. Rumbling sounds were heard by residents in Anoling. The Alert Level was raised to 2 (on a 0-5 scale). Faint crater incandescence was first observed at 2216. A phreatic eruption began at 0849 on 14 January and lasted about five minutes, and another was detected at 1143 and lasted 15 minutes. Steam-and-ash plumes from both events rose from the crater but were mostly obscured by weather clouds. Anoling residents noted rumbling sounds and a sulfur odor, and minor amounts of ash fell in Camalig. On 14 January PHIVOLCS raised the Alert Level to 3, noting a marked increase in activity characterized by three phreatic eruptions and 158 rockfall events between 1621 on 13 January and 1925 on 14 January. Bright crater incandescence was evident, signifying growth of a new lava dome and lava beginning to flow on the S flank. The report reminded residents to stay away from the 6-km-radius Permanent Danger Zone (PDZ) and the 7-km Extended Danger Zone (EDZ) on the S flank. Three collapses of material occurred on 15 January, producing rockfall or small-volume pyroclastic density currents. They were detected by the seismic network at 0941, 1005, and 1107 and lasted five, seven, and eight minutes, respectively. The first two events appeared to have been from collapses of the lava-flow front and generated ash plumes that drifted SW and ashfall in multiple Barangays including Travesia, Muladbucad Grande (8 km W), Maninila, and Masarawag (5 km W) of the Guinobatan municipality, and several Barangays in the Camalig municipality. An ash plume from the third event rose about 1 km above the crater and drifted WSW. During 15-16 January the new lava dome in the summit crater continued to effuse. Lava flows advanced 2 km down the Miisi drainage (S), and a small-volume flow was emplaced on the upper slopes of the Bonga drainage (SSE). The seismic network recorded multiple events including short-duration lava fountaining, 75 lava-collapse events corresponding to rockfalls along the front and margins of advancing lava, and short pyroclastic flows in the Miisi drainage. Ash plumes from collapse events in the summit crater produced ash plumes that rose 2 km and caused ashfall in Camalig, Guinobatan, and Polangui.

Nevados de Chillan | Chile : Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) reported that during an overflight of Nevados de Chillán's Volcán Arrau dome complex on 9 January scientists observed a new lava dome in the active central crater, corresponding to a new fissure first identified on 21 December 2017. Gas and water vapor rose from the fissure going across the dome surface, and the temperature of the surface was about 480 degrees Celsius. The Alert Level remained at Yellow, the middle level on a three-colour scale, and the public was reminded not to approach the craters within a 4-km radius.

San Miguel | El Salvador : SNET reported that at 1653 on 14 January and 1615 on 15 January gas-and-ash plumes from San Miguel rose no more than 300 m above the crater rim and dispersed SW. The report noted that prior to both emissions seismicity decreased and then suddenly increased.