Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 31 January - 6 February 2018

Fuego | Guatemala : INSIVUMEH reported that the first Strombolian eruption at Fuego in 2018 began on 31 January, after a thermal anomaly was detected in satellite images the day before. Explosions produced ash plumes that rose 1.5 km above the crater and drifted 20 km SW. Lava fountains rose 300-500 m, and fed lava flows that traveled 800 m W in the Seca (Santa Teresa) drainage and 600 m in Las Lajas (SE) and Honda (E) drainages. On 1 February the eruption style changed to Vulcanian. Pyroclastic flows mainly descended the Seca, Trinidad (S), Las Lajas, and Honda drainages. Ash plumes from explosions rose 3.2 km and drifted more than 60 km NE, SW, and W. Ashfall was recorded in areas downwind including Santa Sofía (12 km SW), Morelia (9 km SW), Panimaché I and II (8 km SW), El Porvenir (8 km ENE), Sangre de Cristo (8 km WSW), Finca Palo Verde, San Pedro Yepocapa (8 km NW), Ciudad Vieja (13.5 km NE), Antigua Guatemala (18 km NE), and W and SW Ciudad de Guatemala. CONRED reported that 2,880 people were evacuated. At 1630 INSIVUMEH noted that the Strombolian-Vulcanian eruption phase had finished, 20 hours after it had begun. Explosions continued, generating ash plumes that rose just under 1 km and drifted 15 km SW. On 2 February there were 3-5 weak explosion recorded per hour, with ash plumes rising 750 m and drifting 5-8 km W, SW, and S. Shock waves and rumbling were noted, and the lava flows remained visible. During 4-5 February ash plumes from explosions (about 5 per hour) produced ash plumes that rose 700 m and drifted W and SW. Incandescent material was ejected 200 m above the crater, causing weak avalanches of material around the crater area and in some vegetated areas.

Kadovar | Papua New Guinea : RVO reported that the eruption at Kadovar continued during 31 January-1 February at a low level. Sulfur dioxide emissions and seismicity had both decreased. Dense white vapor plumes rose 100 m from Main Crater and drifted SE. Continuous but dull glow emanated from the crater. The lava dome at the SE Coastal Vent continued to grow. A new lobe 20-30 m long grew out from the seaward side of the dome boundary, channeled by levees which had developed on the sides of the dome. White steam plumes rose 100 m above the island and drifted SE. At 1830 on 1 February a collapse of the N part of the dome produced a gray plume, vigorous steaming at the collapse site, and nighttime incandescence. The main part of the dome had bulged up, and a valley developed in between the dome and the island’s flank.

Karangetang | Siau Island (Indonesia) : In a VONA issued on 2 February, PVMBG reported an eruption at Karangetang, characterized by crater incandescence and an ash plume that rose 600 m. The Aviation colour Code was raised from Unassigned to Yellow.

Mayon | Luzon (Philippines) : PHIVOLCS reported that during 31 January-6 February daily activity at Mayon continued to be characterized by lava effusion from the summit crater, rockfalls, pyroclastic flows (31 January-1 February), ash and steam emissions, advancing lava flows on the flanks, and weak and sporadic lava fountains. Numerous rockfall events were generated by the growing and collapsing summit lava dome and from the front and margins of advancing lava flows. On 31 January pyroclastic flows traveled as far as 2 km in the Mi-isi (S), Basud (E), and Bonga (SE) drainages. White-to-light-gray ash plumes generally rose to low heights, though five events generated ash plumes that rose as high as 1 km above the crater rim. An event on 2 February also produced an ash plume that rose 1 km. The first of two lava fountaining events on 4 February lasted sporadically for 114 minutes, generated an ash plume that rose 500 m, and produced booming sounds heard within a 10-km radius. During 5-6 February high volumes of effused lava extended the lava flows in the Mi-isi, Bonga-Buyuan, and Basud drainages to 3.2, 4.5, and 3 km, respectively. The Alert Level remained at 4 (on a 0-5 scale) and the public was warned to remain outside of the Danger Zone defined as an area within an 8-km radius.

San Miguel | El Salvador : On 2 February SNET reported that seismicity at San Miguel was decreasing, along with a decrease in emissions. RSAM values fluctuating between 63 and 114 units; normal values are between 50 and 150. Small pulses of gas near the crater rim were visible.