After the eruption of February 1 and 2, 2018 in Fuego, and the pyroclastic flows in the Seca, Trinidad, Las Lajas and Honda barrancas, a review of the satellite and in situ photographs shows the importance of these, more especially in the Honda barranca.
Fuego - Sentinel 2B images from 25.01.2018 and 04.02.2018 / Bands 4-3-2 - Courtesy of Rüdiger Escobar Wolf
Fuego - deposits of pyroclastic flows from the eruption of 02.02.2018 in the barranca Honda - photo Gustavo Chigna / Twitter
Rüdiger Escobar Wolf / Michigan Tech University compared the Sentinel 2B images of January 25th / before the eruption with those of February 4th / after the eruption of the Honda barranca.
In the images 4-3-2, we see the bleaching of the area covered by the pyroclastic flows; it corresponds to photos taken in situ by Gustavo Chigna.
Fuego - Sentinel 2B images of 25.01.2018 and 04.02.2018 / bands 12-8a-5; the comparison shows the areas covered with ash by the eruption - Courtesy of Rüdiger Escobar Wolf
Fuego - Sentinel 2B NDVI difference between Sentinel 2B images from 25 January and 4 February 2018 - Courtesy of Rüdiger Escobar Wolf
The images of the same dates on the Visible - NIR bands, and the NDVI difference (*) show that the vegetation of the southwest flank was covered with ash.
(*): The Standardized Difference Vegetation Index (NDVI) is a simple graphical indicator that can be used to analyze remotely sensed measurements, from a satellite platform or satellite imagery, and assess whether the target observed contains living green vegetation.
Pacaya - Shift to the south of the hot spot on 04.02.2018 on the image Sentinel2B / tapes 12-11-5 - Courtesy of Rüdiger Escobar Wolf
At Pacaya, the examination of Sentinel2B satellite images bands12-11-5 of February 4 suggest a change in the hot spot, perhaps a lava flow, from the southwest of the summit to a more southerly position. A thermal anomaly of 226 MW was reported on 07.02.2018 by the site Mirova Modis.
The dome still has fumaroles of white color, rising about fifty meters above the crater, then moving towards the west. Small strombolian explosions expel materials between 25 and 50 meters above the crater. Seismicity is related to degassing, rising magma and occasional explosions.
Sources: Insivumeh, Rüdiger Wolf Escobar / Michigan Tech University, & Gustavo Chigna.