The activity of the volcano has been showing a declining tendancy over the past weeks. Explosions are now of a smaller magnitude, releasing less ash with the columns not reaching such high altitudes. The SO2 fluxes are now getting harder to measure with only a small continuous gas release from the volcano. Fieldwork continues at CIIV, with the photo showing San Antonio, recently visited for continued studies of the PDC deposits that were produced during July 2015. You can see how erosion from the rain has cut a considerable channel already in the deposits. Only the top couple of metres were from the 2015 event, the rest being from material from older PDCs remobilized by lahars. This ravine received a smaller volume than the main deposit in Montegrade, with the flow jumping from one ravine to the other on a bend in Montegrande.
It was time to get the batteries which used to power the Doppler radar station before it was destroyed by the July 2015 eruption, during which a large PDC swept down the Montegrande ravine. Further activities were investigating some rather interesting surge deposits, block collisions in the PDC deposit, and starting a photogrammetric survey of the 2015 lava flow. The rainy season on the horizon will destroy the "tracks" bulldozed in the fresh deposits, making access more difficult.
The producer and cameraman of the Central Mexico episode of a future documentary about the country were in Colima over the last 2 days to film the volcano. CIIV helped them obtain images from Volcancito of the volcano. Unfortunately there were less explosions whilst they were here, though a drone was used to get fantastic images of the growing and exploding lava dome.
A slowly growing dome was observed during a recent CIIV flight over the volcano. It has a diameter of only 25 m at the moment and is clearly being disrupted by increasing explosivity. It was not a surprise since nightly incandescence seen over the crater could have only meant one thing. The event marks a break in over 5 months with purely explosive activity. High temperatures (almost 700 degrees) were measured at this stage mainly due to the small dimensions and high proportion of fresh material.
This week sees the visit of Sylvain Charbonnier and Zachary Atlas from the University of South Florida. We are continuing collaboration with a study of the July 2015 erupcion PDC deposits and changes on the petrology of recent eruption projects. We hope this will help pave the way for future exchange visit between students at the two universities. Sylvain is shown here with his student Elodie who is working on the study of the PDC deposits.