Photo taken from the 17H00TL OVT, February 5, 2014. The column goes towards the S-SE.
The seismic record associated with the surface manifestations has varied between periods of several hours with few seismic events followed by others with frequent explosions of small to moderate magnitudes and also the emergence of important bands of tremor (seismic vibration continues) that lasts about 15 minutes or more.
It is during these events that tremor similar to a locomotive (chug-chug) sound is heard and there is a greater output of incandescent material, the columns are taller and small pyroclastic flows occur occasionally. Also very vigorous jets loaded with ash up to 4 km above the crater (Fig. 3) are observed.
Figure 3: