Guest post from Tallis
Lately, I have been researching 2 volcanoes and have found something disturbing to myself for a variety of reasons. I’m sure you have heard of these volcanoes but maybe, since there is a lack of attention on these volcanoes, that you have missed out on some valuable information. I am not a scientist and I am about to talk about high-risk volcanoes that are experiencing unrest as we speak. Please know that I am not trying to sound alarmist and I beg of you to challenge my words, propositions, and points. I hope through some sporting debates with my worthy rivals and superiors, we can establish more facts and possibilities.
Central American volcanoes are overlooked as we have already discussed and that is unfortunate considering that one scary volcano lives right there, in fact, there are two, or at least there are two volcanic peaks in close proximity. Cerro Negro De Maseyquer with its neighbour Chiles are on the border between Colombia and Ecuador. (Note: not to be confused with Cerro Negro in Nicaragua.) It is no stranger to the news: just several years ago it made headlines for its seismic crisis but the seismic activity went down and so did its attention. I have been looking at this volcano for a couple of years now and it never did catch my interest until recently.
Cerro Negro is a stratovolcano with a 1.8 km crater opening to the west. Andesitic and dacitic lava flows are of possible Holocene age and solfataras found on the shore of a small crater lake show recent volcanic activity. Chiles lies only 3 km to the SE, and is A higher, glacier-covered stratovolcano which last erupted about 160,000 years ago. It has hot springs and an active hydrothermal system at its eastern flank. The earthquake swarm started in July 2013, in relatively shallow depths from 1 to 17 km reaching magnitudes up to 4.5
This volcano in the past year has had more than 147,000 earthquakes, starting in September 2018 and still reported in progress as of 1 August 2019. A magmatic component was present in the earthqukes. This interested me a little bit and with a quick search on Google, I noticed that there has been no significant gas emission or deformation so I quickly moved on until I realized something. There SHOULD BE some significant deformation and gas emissions. The seismic crisis was caused by a magma intrusion and some of the more recent earthquakes are caused by the changes in the magma chamber’s pressure but I don’t know how many exactly.
Either the intrusion or the pressure should be creating significant deformation right now but there is still none. The weirder thing is, that you have to go back to the seismic crisis to get all of the signs of unrest before 2 out of 3 stopped. What happened? One theory is that the magnitude 5.6 earthquake inhibited the pathways of magmatic fluid into the system during the seismic crisis, the other theory is that the tectonic setup, as well as the fact that the volcanoes haven’t erupted in over 10,000 years, could also mean there too much compressive force for there to be significant uplift and the deformation during the unrest was due to the earthquake.
That’s it. That is pretty much all of the data I could find for the unrest. No data on the status of the magma chamber, no more data on the scale of the intrusion, and the issue of what exactly is going on is still a mystery. There are so many different future scenarios that it is ridiculous. Once my frustration peaked I had a Gordon Ramsay moment, I yelled “Where are my spectrograms?! Where’s my daily earthquake count?! Where’s my GPS monitoring devices?! Why isn’t there a daily record of volcanic strain!?” None of this data is public or in existence.
I am going to give my idea of what I think is happening, I believe the major earthquake during the seismic crisis inhibited deformation and gas emissions. It enhanced the compressive nature of the geological setup but didn’t limit the magmatic intrusion. This is because even after the earthquake the swarm continued at high levels for months and the recent swarm is the result of the magma chamber pressurizing.
The current swarm is also on a downward trend but this might not be a good thing, it could mean that the magma chamber is reaching its pressure limit. What proof do I have? None. That makes me all the more worried but there is a silver lining, before a hypothetical eruption, there would large earthquakes and a LOT of uplift before an eruption.
The scariest part of this for me is that the magma is likely to be sulfur-rich and the region has had large eruptions where 2% of the erupted mass was sulfur dioxide and if even half of that percentage were to happen with a VEI 5 or VEI 6 it would suck.
At least this volcano has easy to access information. The state of the Corbetti caldera in Ethiopia is even harder to understand. The best information I could find is the fact the volcano seems to be receiving an average of 10^7 cubic meters of magma a year as well as experiencing deformation and microseismicity. That is it. These volcanoes could threaten over 100,000 people with smaller eruptions. These volcanoes are capable of producing VEI 7 eruptions and while I am not saying that is what is going to happen in the future but we should have enough information as curious minds to safely write that off as an issue.