Colima – Living in the shadows of an active volcano
The geologist Irving Munguia talks about his experience of living with an active volcano.
Volcán de Colima (short Colima) in Mexico erupted more than 50 times since the 16th century. Explosive, but short-lived Vulcanian and phreatic eruptions, as well as lava flows are the most common. A so-called lava dome often forms in the crater through the extrusion of highly viscous lava, which piles up over the vent instead of flowing down the flanks. However, Colima can also be a lot more violent: in January 1913, a Plinian eruption produced an eruption column with a height of 23 km and more than 0.6 km3 of new volcanic material.
But the more common Vulcanian eruptions are not to be underestimated either, since they are associated with ash clouds and several types of pyroclastic flows. The volcano is in an eruptive episode since 2013. Explosions, ash emissions, lava flows and debris avalanches are frequent and a new dome started growing in the crater in February last year.
More than 300,000 people live within 30 km of Mexico’s most active Volcano, almost 1.5 Million live within 100 km. Irving Munguia grew up in Colima, the city at the foot of the volcano. After his undergraduate degree in Geology in Mexico, he moved to the UK, where he is currently doing his PhD at the University of Bristol. The topic of his PhD research is – unsurprisingly – his „home volcano“, which he talks about in an interview with ESKP.
Despite seeing the volcano having an explosion a few times per day while walking or driving through Colima city, I have to say that, as a local, you learn to ignore the presence of the volcano almost completely unless you are directly affected by its activity. We, the people of Colima city, live our day to day life almost without noticing that the volcano is pretty much in our backyard. However, sometimes significantly big explosions can produce ash-falls and/or compression waves in the air that shake walls and even shatter windows, reminding us that the volcano is there. Those are the most common events, which cannot go unnoticed by the inhabitants of Colima, since they have a direct and immediate impact up to many tens of kilometres around the volcano.
Having the so called “most active volcano in North America” right next to you all the time and not knowing how it works, what it does and what it could do, was intriguing. I grew up impressed by the daily eruptive columns that crowned the top of the volcano and by the idea of how the volcano could look like inside. There is a 7 to 10 km exclusion zone around Colima, which normal people are not allowed to intrude for their own safety. I did not want to be a ‘normal person’ - instead, I wanted to be part of the people who can get closer, to find out what was happening. In order to investigate the volcano, I needed to become a volcanologist and so I started my way to become one.
Within the population of Colima there is an unconscious contradiction between ignoring the presence of the volcano, unless we are directly affected by its activity, and a fear of the uncertainty of what could happen if the volcano “explodes” really badly all of a sudden. As my major change due to becoming a volcanologist I can perhaps identify that it considerably minimised the “fear” of a sudden destruction by the volcano. I was able to get a sense of how likely the occurrences of different types of volcanic events are, to what extent they could affect the surrounding populations, what monitoring and forecast techniques exist to be informed about these events, and where to search for information about the volcanic activity. Therefore, I believe that communicating simple but detailed information about Colima and its associated activity to the surrounding population could not only help people to be more aware of changes in the activity of the volcano (information which is provided by the local authorities). But it also provides them with a clearer concept of the different styles of eruptive activity and helps to self-evaluate the potential effects that these could have in their lives and the probabilities for them to occur.
From a statistical point of view, events like ash-falls and lahars (mud and debris flows) could be acknowledged as the major hazards of Colima considering the frequency in which they occur and the distance they reach. However, threats are not exclusively attributed to the volcanic activity: the most hazardous instances can result from the people themselves, when they settle or wander too close to the volcano (within an established exclusion zone). Those self-risk scenarios can be either due to ignoring the range of some volcanic events (including pyroclastic flows, lava flows and material ejected from explosive events) or by not caring much about them.
Within a short distance, it has killed some livestock of ranches near the pathways of pyroclastic flows; at medium distance, the generation of acid rain burned and damaged some crops. At a larger distance, there have been disruptions of the local airports due to ash-falls, and people were irritated by all the “dirt” that the volcanic ash produces. On a more positive side, the current activity, combined with increasing use of social media, has made people much more aware of and interested in the development of the volcanic activity at Colima.
Unfortunately, accurate estimations on the evolution of the ongoing and future activity at Volcán de Colima cannot be done a hundred percent and, as in previous crises, the volcano could have an almost sudden shift in activity from very frequent explosions to another quiet stage. However, there is a current hypothesis regarding the activity of Colima that says that the volcano behaves in a centennial cyclic way. After a very big eruption (Plinian or sub-Plinian), the volcano starts a cycle of alternating effusive and minor explosive activity, with an increasing frequency and magnitude of the activity as the end of the cycle approaches. Finally, this culminates in another major Plinian explosion after which a new cycle begins. Based on this hypothesis, and considering that the last Plinian eruption occurred about a hundred years ago and that the frequency and magnitude of the current activity is increasing, it has been suggested that the volcano could be heading towards another Plinian event sooner rather than later.