After over 6 months of relative calm the seismicity suggests that a new magma batch is rising and may have already reached the surface. The weather hasn't been great and a flight has been planned for a while. Now it is more urgent to see what is inside the crater. In the photo you can see the large amount of erosion in parts of the Montegrande ravine from the rains during the past weeks. The chance of a large lahar is ever increasing as the channel develops along the whole ravine within the 2015 PDC deposit.
The volcano has become uncharacteristically calm. After the last large event on the 3rd Feb. we have seen very few small explosions. The gas flux has increased suggesting a less sealed system but seismicity still suggests there is magma moving but maybe very slowly. The photo shows the large ash cloud from the 3rd Feb. event taken from the city.
An eruption occurred in the early hours of the 18th Jan. and it has been heralded as one of the most dramatic night-time eruptions seen in recent years. Granted, it looks spectacular on the webcams de Mexico video. However, the explosion did not produce as much seismic energy as the larger events that occurred in 2005 (when there were no publically available images or social media). It is an interesting way to start 2017 and if the similarities with 2005 continue, we may see a lot more events like this and getting larger. There is clearly a large degassing magma body at depth and monitoring is currently critical. The only photos so far are from the reliable webcamsdemexico.com.
After trying to fly for several weeks, finally we managed to have the right conditions and 5 willing participants. After having measured high temperatures earlier in the month (highest temps. yet measured for this volcano) the temperatures were much lower with a maximum of only 320° C. This reflects the reduction in the effusion rate. The eruption is shifting from passive magma emplacement to the more common small Vulcanian eruptions occurring at least once per hour.
A flight over the volcano enabled us to determine that the dome was still growing, though at a very slow rate. The size of the dome had not increased by much, however, the surface temperature indicated active effusion.