Report on Tungurahua (Ecuador) — June 2008
Bulletin of the Global Volcanism Network, vol. 33, no. 6 (June 2008)
Managing Editor: Richard Wunderman.
Tungurahua (Ecuador) Explosions up to 14 km altitude during July 2007 to February 2008
Please cite this report as:
Global Volcanism Program, 2008. Report on Tungurahua (Ecuador) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 33:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200806-352080.
1.467°S, 78.442°W; summit elev. 5023 m
All times are local (unless otherwise noted)
Our previous report on Tungurahua (BGVN 32:08) discussed the volcano's activity during March-July 2007. During that period, Ecuador's Instituto Geofisico (IG) reported significant, but variable eruptive behavior, along with many lahars, ash plumes that reached 4 km above the summit, and semi-continuous ashfall.
Table 15 presents a brief summary of the weekly activity at Tungurahua between 18 July 2007 and 19 February 2008. The plumes were described variously as ash, ash-and-gas, steam-and-gas, steam, or steam-and-ash. They rose up to 13 or 14 km altitude (25-26 October 2007 and 7 February 2008, respectively) but more typically, for many weeks, to below 8 km altitude. Around December 2007 IG stated a caution. They likened Tungurahua's behavior as similar to after its explosive phase of 14 July 2006. In that case, volcanic activity kept going, and this lead to the most explosive phase on 16 August 2006. That dramatic pattern was not repeated the next month, but the pace of volcanism kept up and led to the vigorous 7 February eruption.
|18 Jul-24 Jul 2007||5.2-8 km||Roaring, noises resembling cannon shots or rolling blocks, lahars, ashfall.|
|25 Jul-31 Jul 2007||up to 2-3 km above crater||Many small ash-bearing explosions and several unusually large ones, blocks fell up to 0.5 km below crater's rim, ashfall.|
|01 Aug-07 Aug 2007||up to 5.5 km||Roaring, explosions, rolling blocks, steam emissions, ashfall.|
|08 Aug-14 Aug 2007||up to 6 km||Explosions, incandescent material fell inside the crater and on the flanks, ashfalls, lahars down NW drainage disrupted road traffic between Ambato and Banos.|
|15 Aug-21 Aug 2007||5.5 km||Cannon shot noises, explosions, ash emissions, ashfall.|
|22 Aug-28 Aug 2007||6-9 km||Explosions, incandescent blocks down flanks, lahars in the NW drainage disrupted road traffic, ashfall.|
|29 Aug-04 Sep 2007||7 km||Explosions, roaring and cannon shot noises, incandescent blocks ejected, lahars disrupted road traffic, ashfall. On 4 September incandescence and rolling blocks on the E and N flanks.|
|05 Sep-11 Sep 2007||5.3-8 km||Explosions, incandescent blocks rolled down flanks, ashfall.|
|12 Sep-18 Sep 2007||5.5-8 km||Strombolian eruption, explosions, incandescent material ejected above the summit and blocks rolled 100 m down the flanks, roaring and cannon shot noises, ashfall.|
|19 Sep-25 Sep 2007||5.3-7 km||Explosions, roaring and cannon shot noises, incandescent material ejected above the summit and blocks rolled 500 m down the flanks, ashfall.|
|26 Sep-02 Oct 2007||6-7 km||Roaring and cannon shot noises, 28 September, blocks ejected above the summit and descended 500 m down the flanks, ashfall.|
|03 Oct-09 Oct 2007||6-8 km||Ash plumes, roaring and cannon shot noises, noise of rolling blocks, ashfall.|
|10 Oct-16 Oct 2007||6.2-8 km||Ash plumes. During 11-12 October incandescent blocks ejected and descended 300 m down the W flank; roaring noises from multiple areas on 11, 13, and 14 October. Ashfall.|
|17 Oct-23 Oct 2007||5.5-9 km||Ash plumes. 17 October, roaring, incandescent material erupted from the summit fell onto the flanks. Fumarolic activity on NW flank, lahars closed road on NW drainage. Ashfall SW on 21 October.|
|24 Oct-30 Oct 2007||up to 13 km||Ash and steam plumes. 25-26 October, incandescence at summit, roaring and cannon shot noises, blocks rolling down the flanks; ashfall.|
|31 Oct-06 Nov 2007||5.5-8 km||Explosions, roaring, incandescent blocks at summit, lahars closed road, ashfall.|
|07 Nov-13 Nov 2007||6-9 km||Roaring and cannon shot noises, incandescent blocks rolled a few hundred meters (1 km on 12 Nov) down the flanks, fumarolic activity, lahar, ashfall.|
|14 Nov-20 Nov 2007||up to 7.3 km||Roaring and cannon shot noises, incandescent blocks rolled down flanks, thermal anomaly detected.|
|21 Nov-27 Nov 2007||6-8 km||Explosions, roaring, incandescent blocks 1 km down the flanks, lahars (4-5 m high in one area) closed road, ashfall.|
|28 Nov-04 Dec 2007||6-8 km||Elevated seismicity, explosions, continuous emissions of steam and ash, roaring and cannon shot noises, incandescent blocks 0.5-1 km down flanks, ashfall.|
|05 Dec-11 Dec 2007||6-8 km||Explosions, roaring and cannon shot noises, incandescent material about 1 km down flanks, ashfall.|
|12 Dec-18 Dec 2007||6-7 km||Explosions, roaring and cannon shot noises, almost constant emission of of ash plumes, incandescent blocks rolled down flanks, ashfall.|
|19 Dec-25 Dec 2007||6-8.5 km||Roaring and cannon shot noises, incandescent blocks hundreds of meters down flanks, ashfall. News reports indicated that 1,200 people from Penipe were evacuated nightly.|
|26 Dec-01 Jan 2008||6-8 km||Explosions, roaring, and cannon-shot noises, incandescent blocks 500 m down flanks, ashfall.|
|02 Jan-08 Jan 2008||5.5-8 km||Explosions, roaring and cannon shot noises, continuous ash emissions, incandescent blocks 500 m down flanks, ashfall. News reports indicated that nearly 1,000 people were evacuated for the night on 6 Jan.|
|09 Jan-15 Jan 2008||6-9 km||Strombolian eruption, roaring and cannon shot noises, incandescent blocks 0.5-1 km down flanks. News reports indicated that residents from two provinces evacuated at night and about 20,000 health masks were distributed in Banos and Quero.|
|16 Jan-22 Jan 2008||5.5-9 km||Strombolian eruption, roaring and cannon shot noises, incandescent blocks 1-2 km down flanks, small pyroclastic flow 400 m down NW side of crater, ashfall.|
|23 Jan-29 Jan 2008||5.5-9 km||Roaring and cannon shot noises, incandescent blocks 500-800 m down flanks, lahars blocked road to Banos, ashfall up to at least 40 km from summit.|
|30 Jan-06 Feb 2008||6-9 km||Explosions (65-208 per day), roaring and cannon shot noises, incandescent blocks rolled 600 m down flanks, lahar, ashfall.|
|06 Feb 2008||--||New phase of eruptions began with a moderate explosion.|
|07 Feb 2008||6-14.3 km||Tremors of variable intensity, ash columns to heights of 3 km beginning a new phase of eruptive activity; satellite images show a hot spot in the crater. Strombolian eruptions, explosions, strong roaring and cannon shot noises, incandescent material rolled 1.2 km down the flanks, tremors followed by pyroclastic flows on the NW and W flank, tephra fall SW, ashfall. News articles stated several hundred to 2,000 people evacuated.|
|08 Feb 2008||--||Internal volcanic activity as well as emissions of ash, incandescent material, and explosions and roaring noises slowly diminished; current eruptive episode should not be considered as finished.|
|09 Feb-12 Feb 2008||--||Strombolian eruptions, explosions, strong roaring and cannon shot noises, incandescent material rolled 1.2 km down the flanks, pyroclastic flows, tephra fall, ashfall. News articles stated several hundred to 2,000 people evacuated.|
|13 Feb-19 Feb 2008||6-9 km||Roaring, noises resembling blocks rolling down flanks, lahar, ashfall.|
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.
Information Contacts: Geophysical Institute (IG), Escuela Politécnica Nacional, Apartado 17-01-2759, Quito, Ecuador (URL: http://www.igepn.edu.ec/); Washington Volcanic Ash Advisory Center, Satellite Analysis Branch (SAB), NOAA/NESDIS E/SP23, NOAA Science Center Room 401, 5200 Auth Rd, Camp Springs, MD 20746, USA (URL: http://www.ospo.noaa.gov/Products/atmosphere/vaac/); Reuters (URL: http://www.reuters.com/); Associated Press (URL: http://www.ap.org/); Pan American Health Organization (PAHO), 525 23rd St. NW, Washington, DC 20037, USA (URL: http://www.paho.org/).