Roundup of Global Volcanic Activity – New Activity for the week of 3 May – 9 May 2017
Aira | Kyushu (Japan) : JMA reported that nine events at Showa Crater (at Aira Caldera’s Sakurajima volcano) were detected during 1-8 May. One of the events was explosive, generating an ash plume that rose 4 km above the crater rim and ejecting material 300-500 m from the crater. Ashfall was reported in the cities of Kagoshima (3 km NW), Hioki (25 km WNW), and Ichikikushikino (40 km NW). Nighttime crater incandescence was noted on 2 and 5 May. An event at 1213 on 5 May at Minamidake summit crater produced a plume that rose 500 m above the crater rim. The Alert Level remained at 3 (on a 5-level scale).
Fuego | Guatemala : In a special report INSIVUMEH reported that a new phase of activity (the fourth of the year) at Fuego began on 5 May and was the strongest activity recorded since 2012. Strong explosions, sometimes producing shock waves, generated dense ash plumes that rose 1.3 km above the crater and drifted more than 50 km S, SW, and W. Ashfall was reported in many areas downwind, including San Pedro Yepocapa (8 km N), Morelia (9 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), finca Palo Verde, Santa Lucia Cotzumalguapa (23 km SW), Siquinala, San Andrés Osuna, Chuchu, and La Reunión. Lava flows traveled 2 km down the Santa Teresa (W) drainage and 3 km down the Las Lajas drainage. Pyroclastic flows descended the Trinidad (S), Las Lajas (SE), Ceniza (S), and Santa Teresa drainages. Residents of Sangre de Cristo (8 km WSW) were evacuated. Explosions were not reported that next day and the lava flows may have stopped advancing. According to a news article, about 300 people had been evacuated from Panimache (8 km SW). During 7-8 May lower-energy explosions generated ash plumes that rose as high as 750 m above the crater and drifted 8-20 km W and SW. Gases were observed rising from pyroclastic flow deposits in the ravines.
Manam | Papua New Guinea : RVO reported that another phase of Strombolian activity at Manam’s Southern Crater began around 1700 on 4 May when RSAM values increased to 100-150. A sharp increase in values was detected at 0330 on 5 May, though the highest RSAM value (1,400) occurred between 0500 and 0600. RSAM dropped rapidly to 200 by around 0700, and then by 1400 RSAM values were around 50. Strombolian activity on 5 May was characterized by loud roaring and rumbling, ejected incandescent material, and ash and scoria fall; some phases of very strong activity occurred during 0530-0600. A lava flow traveled down the SW valley and stopped at 600 m elevation. Minor amounts of ash fell in all parts of the island including Warisi (E), Dugulaba (S), and Boda and Baliab (NW). Though weather clouds prevented visual observations of Manam during 6-8 May, activity in general was very low; noises and crater incandescence were absent, and seismicity was lower than it had been for many weeks (RSAM
Poas | Costa Rica : OVSICORI-UNA reported that an eruption at Poás was detected at 1724 on 6 May though poor visibility prevented visual confirmation of the event. During 6-7 May volcano-tectonic and long-period earthquakes were detected, as well as moderate-amplitude tremor.