Orange Alert after renewed eruption activity of the Tungurahua Volcano, Ecuador
Last update: December 1, 2011 at 5:06 pm by By Armand Vervaeck
Both, the Tungurahua volcano and the neighboring Sangay volcano are belonging to the most active volcanoes of Ecuador. Although the volcano has an almost permanent state of activity, authorities had to call an Orange alert after incandescent flows and some violent explosions.
Recent and current Activity
Since this morning the intensity of emissions (gas and ash) tends to decrease, said the Geophysical Institute of Ecuador in a report. Seismic activity associated with emanations is continuing. Ashfall and 8 minor explosions were reported in the villages surrounding the volcano. No pyroclastic flows or expulsion of incandescent rocks from the crater have been seen recently. Emergency services have told villagers to stay away from river valleys if it would be raining, as the recent pyroclastic flows can create dangerous land/mud/slides of pyroclastic material.
A total of 638 families living in three parishes in the Tungurahua volcano area received relief by the SNGR. People living near the the volcano are used to the activity as there is always some continuing seismic activity.However, the authorities decreed on Sunday an orange alert due to the sudden increase in eruptive activity.
Various relief agencies in the province provide help to the inhabitants of Cotaló, Cusúa, Bilbao, Chacauco, Pillate and other sectors affected by the volcano into reaching evacuation trucks which will transport them to shelters in in La Paz and Riobamba.
The ‘Guadalupe’ Center which is monitoring Tungurahua reported constant explosions (windows rattled at the center) + an ash cloud which rose to more than two kilometers.
At 02:00 on 28 November an explosion ejected incandescent material that fell on all flanks, and generated a pyroclastic flow that descended the Achupashal drainage. Starting before 0500 until 0900 an almost constant roar was heard and incandescent blocks traveled 1 km down the flanks, especially towards the W and NW.
Three pyroclastic flows were noted on the S flank.
Windows vibrated at the Tungurahua Observatory (OVT) in Guadalupe (14 km N). During the day, an ash plume rose 3 km above the crater and drifted in multiple directions. White ashfall was reported in Manzano, Choglontús (SW), Pondoa (8 km N), and Runtún (6 km NNE). In the evening incandescent blocks that were ejected 300 m above the crater rolled 400-500 m down the flanks. On 29 November an explosion detected at 0611 produced a small pyroclastic flow that traveled 500 m. Another pyroclastic flow at 0955 traveled 1 km W. Gas-and-ash plumes rose 4 km above the crater and drifted SE and W. According to a news article, people in high risk areas on the flanks, in communities such as Cusúa, Juive, Palictahua, and Manzano, evacuated voluntarily.
IG reported that increased seismicity from Tungurahua was detected at 15:40 on 27 November, and at 16:50 the seismic network recorded 4 volcano-tectonic earthquakes. Two small explosions at 17:01 and 17:05 were followed by a large explosion at 17:18.
Pyroclastic flows descended the Achupashal, Chotanpamba, and Mandur drainages on the NW and W flanks. Two more large explosions were detected at 17:31 and 17:35.
Incandescent blocks traveled 1 km down the flanks, and roaring noises and sounds resembling “cannon shots” were reported. Ashfall was reported in Manzano (8 km SW), Bilbao (8 km W), and Pillate (8 km W), ash and tephra fell in Cotaló (8 km NW), and tephra fell in Cusúa (8 km NW).
At 19:05 a pyroclastic flow descended the S and SW flanks.
Global Volcanism Program information
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.