Report on Tungurahua (Ecuador) — 12 February-18 February 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 12 February-18 February 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on Tungurahua (Ecuador). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 12 February-18 February 2014. Smithsonian Institution and US Geological Survey.
1.467°S, 78.442°W; summit elev. 5023 m
All times are local (unless otherwise noted)
IG reported that on 11 February explosions from Tungurahua generated ash plumes that rose 3 km above the crater and drifted WNW. Roaring noises and sounds resembling blocks rolling down the flanks were noted. A small pyroclastic flow traveled down the flanks at 1720, and ashfall was reported in El Manzano (8 km SW). Incandescence on the N flank was observed at night during 12-13 February. Ash plumes again rose 3 km on 13 February causing ashfall in Choglontus (SW) and Capil. During 13-14 February Strombolian activity ejected blocks that rolled 500 m down the N flank. Ash plumes rose 3 km and drifted W, and minor amounts of ash fell in Tisaleo (29 km NW). Cloud cover prevented views on 15 February; ashfall was reported in Penipe (15 km SW). During periods of clear weather on 16 February observers noted that ash plumes rose 3 km. Ash fell in Runtún (6 km NNE), Penipe, and El Manzano. At night during 16-17 February incandescence from the crater was observed along with blocks that rolled 500 m down the flanks. Gas-and-ash plumes rose 5 km and drifted N, NW, W and SW, and ashfall was reported in Penipe, Chacauco (NW), and Pillate (8 km W). An ash plume rose 4 km on 18 February and drifted W. Minor amounts of ash fell in Choglontus.
Geologic Background. Tungurahua, a steep-sided andesitic-dacitic stratovolcano that towers more than 3 km above its northern base, is one of Ecuador's most active volcanoes. Three major edifices have been sequentially constructed since the mid-Pleistocene over a basement of metamorphic rocks. Tungurahua II was built within the past 14,000 years following the collapse of the initial edifice. Tungurahua II itself collapsed about 3000 years ago and produced a large debris-avalanche deposit and a horseshoe-shaped caldera open to the west, inside which the modern glacier-capped stratovolcano (Tungurahua III) was constructed. Historical eruptions have all originated from the summit crater, accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. Prior to a long-term eruption beginning in 1999 that caused the temporary evacuation of the city of Baños at the foot of the volcano, the last major eruption had occurred from 1916 to 1918, although minor activity continued until 1925.