Report on Tungurahua (Ecuador) — 9 July-15 July 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 9 July-15 July 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, 9 July-15 July 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 Tungurahua had low levels of seismicity and poor viewing conditions during 24-27 June and in July during 1-9 and 14. Heavy rain during the night of 24 June and morning of 25 June generated small lahars that caused damage to the Baños- Penipe highway. During the afternoon of 28 June clear viewing conditions allowed observations of a 100-m-high white plume rising from the summit crater. Otherwise, clear conditions revealed quiescence at the summit. Heavy rain during the night of 7 July and the following morning generated lahars in the drainages of Mandur to the NW: Pondoa, Cusúa, and Pingullo. A major road was destroyed in the area of Asupashal and the flow through Juive (NW) carried blocks up to 50 cm. A small lahar on 14 July was detected in the Juive drainage after heavy rainfall during the prior evening.
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.