Tungurahua , Ecuador : moderate surface activity with the presence of small pyroclastic flows.

Tungurahua , Ecuador : moderate surface activity with the presence of small pyroclastic flows.

SCENARIOS AND UPDATING of the eruptive activity of the Tungurahua volcano.

moderate surface activity with the presence of small pyroclastic flows.
March 1, 2016 (16h30TL)

Since the last special report issued on Saturday, February 27, the number of episodes of tremor emission increased as well as explosions and events related to the movement of fluids inside the volcano.

Since its reactivation on Friday, February 26, it was reported glow at night at the crater, emissions of blocks , rumbling, ground and windows vibrations , detonations and small lava fountains.
The tremor registered by retu station (closest to the crater) still shows a high energy level . However, the size of explosions recorded since February 27  remained between low and moderate.

The tremor occurs in bands of varying intensity, and is associated with continuous emission with a low to moderate load of ashes. The column of the highest emission observed from Saturday until today reached 4000 meters above the crater. During these two, the vibration of windows and soil have been reported, in addition to rumblings , turbine type noises recorded by some populations of the western flank of the volcano.

During the last night there was an activity type lava fountain, where the emitted material, for the most part , stayed inside the crater. He was accompanied by rumblings of different intensities, emission of ballistic blocks that reached 1,500 meters above the summit. After a few hours, there was a small pyroclastic flow that descended in the ravines of Jewish, Mandur and Achupashal.

Then, an explosion that produced the descent of a new pyroclastic flow through the canyon Romero was recorded. These pyroclastic flows have remained in the upper middle part of the volcano’s flanks, in uninhabited areas. The largest flow descended into the canyon Achupashal and reached 1,500 meters below the summit.

The most populations affected by ash falls are Choglontús, Cotaló, El Manzano and Palitahua. Other communities were affected, with less ash and are: Bilbao Pillate and some rural municipalities in the canton of Quero.

Regarding emissions of sulfur dioxide, peak flow was 1,544 t / day recorded by Bayushig station on February 27 with 47 valid measurements. For reference, the minimum value in recent weeks was 209 t / d recorded by Huayrapata station on 25 February with 8 valid measures.

No significant changes in gas emissions, deformation, suggesting that the current activity is related to a magmatic intrusion of low volume, so the scenarios for the coming weeks, proposed on February 27, are maintained:

Scenario 1, most likely. The volcano’s activity continues with explosions, emissions and ash fall, which can sometimes be more intense. In addition, they can be small pyroclastic flows, limited to the middle of the flanks of the volcano, similar to those that took place yesterday. These events can occur in the next two to three weeks.
Scenario 2, less likely. A new magma migration to the surface occurs with a large volume and causing paroxysmal eruption similar to that of August 2006.
In cases where significant changes would occur in the monitoring parameters, the Geophysical Institute will update the scenarios that have been proposed.

March 03, 2016. Tungurahua , Ecuador :

Source : GP, BB, AA
Instituto Geofísico
Escuela Politécnica Nacional

Photos : E.P.N. Geophysics Institute / Wikipedia

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