Nevados de los Ruiz (NRV), Tolima, and Santa Isabel are part of something called the Cerro Bravo-Cerro Machín Volcanic Complex (CBCMVC).
That’s more than just a fact that might someday win you money on a game show.
According to this 2016 paper (jargon alert):
…observations suggest that renewed magmatic activity is currently occurring at CBCMVC. NRV shows changes in its activity that may be related to this new magmatic activity. NRV is currently exhibiting the most activity of any volcano in the CBCMVC, which may be due to it being the only open volcanic system at this time. This suggests that over the coming years, there is a high probability of new unrest or an increase in volcanic activity of other volcanoes of the CBCMVC.
Nevado del Ruiz (NRV) woke up in 2012, four years before this paper was published.
There’s no need to panic — this is all playing out over geological time. But it’s important news, and most of us aren’t familiar with that part of the world.
So here is a very brief introduction to those two volcanoes.
This 2012 video shows a group on the summit (cima) 13,000 feet above sea level and in the crater of Cerro Bravo, north of Nevado del Ruiz:
Wikipedia page (Spanish, autotranslated)
What a pretty view! What a nice old volcano; bet it was really something back in its day. Oooh, clouds!
Mind-blowing fact: Appearances are deceiving. Bravo’s GVP-page eruption history shows nothing but VEI 4 eruptions — Mount Merapi 2010 size — the last somewhere between 1570 and 1870 (“a few minutes ago” in geologic terms).
In addition, the GVP activity bulletin has a detailed report of unrest between 2006 and 2012.
Alert level/History: GREEN. This SGC Cerro Bravo page is in Spanish — and won’t go through the autotranslator process — but many browsers do have a “translate” function these days.
We’ll need four-wheel drive for this next one. Oh, look! Cows!
It’s in Spanish, and I can’t help out, but the visuals are nice.
The volcano is that pointy hill behind them, right?
Mind-blowing fact: No, as shown at around 2:20 in the next video, they’re in the volcano, one of the most dangerous in Colombia.
Again, Spanish, but excellent visuals (also a few cows). Here’s the Wikipedia page (Spanish, autotranslated).
The volcanologist they interview in an office also wrote that paper linked above and, as SGC technical director, he has been updating everyone on Nevado del Ruiz.
Alert level/History: YELLOW. Here are the SGC page (Spanish only, as per Cerro Bravo, above) and GVP page.
The GVP doesn’t give VEI values for Machín’s eruptive history. The last one listed is dated somewhere between 1030 and 1330.
This one is a real baddie. SGC has two YouTube videos on it, in Spanish.
Good visuals in this first one. Just look at the size of those lahar deposits!
That will bury the towns, not just the cows and farmland.
And, if you understand spoken Spanish, here is an almost 90-minute talk they gave on Machín last December:
By the way, you can always check out the status of all Colombian volcanoes here (Spanish, no autotranslate but try your browser).
Featured image: Cerro Bravo and its setting, by Luis Perez via Wikimedia, CC BY-SA 2.0.