‘An eruption of the Cotopaxi volcano is not imminent; however, the eruptive history must be considered’: Hugo Yepes, seismologist and adviser to the Mayor’s Office of Quito

The Risk Secretariat declared in October 2022 the state of yellow alert for the area of ​​influence of the Cotopaxi volcano.

The yellow alert was declared under the precautionary principle, in order to maintain and strengthen monitoring and the necessary training, prevention, preparation and response activities, the Government indicated.

Quito is one of the cities that has been affected in recent months by a slight fall of ash, and its authorities carry out continuous monitoring.

Hugo Yepes is a risk advisor for the Mayor’s Office of Quito. He was director of the Geophysical Institute of the National Polytechnic School (EPN) for fifteen years. He is a seismologist and geologist, and earned a Ph. D. in Earth Sciences.

In an interview with this newspaper, he refers to the actions that are being carried out in the capital.

Since last year, in October, the alert for the Cotopaxi volcano changed. As a result of this decision, what is being done in the Municipality of Quito?

A yellow alert implies the need for all institutions and GADs (decentralized autonomous governments) to establish the level of preparation that they have in the face of this phenomenon, which is actually a need for permanent preparation; and, in a way, it is to review, to dust off the response plans and the preparation plans for a potential response to a given impact of the volcano.

Since October, the Municipality has been working on two fronts. The one, attending and responding to what the risk management organization is. It has been responding, meeting the requirements of both the national COE (Emergency Operations Committee) and the provincial COE.

But, on the other hand, also, within what already are the preparations or actions to better understand the problem and prepare according to the magnitude of the potential problems.

What the Municipality has established is a strategy, based on knowledge of the risk, to carry out the different preparation actions in a specific manner.

It has developed what is called the “multi-threat and multi-purpose exposure model”, and this model implies knowing the threats from the territorial point of view; and to each of the buildings, to each of the lots, to give them a characteristic based on that threat.

With the Cotopaxi volcano, work has begun with the exposure model and the hazard impact zones, which are provided by the hazard maps.

It is basically the impact scene of an eruption similar to the one in 1877, transiting the north side of the volcano, which implies a large eruption. And, then, uniting the threat with the exposure, we see what is exposed and (what) are the planes that have to be polished and that have to be activated in case of need.

“Any Ecuadorian government and citizens should be prepared for an imminent strong eruption of the Cotopaxi volcano”

When would these plans be ready?

The Council (Metropolitan) has given a period of two months, since last week, for those plans to be ready. But the important part is that these are plans that are being built participatively with the sectors involved, giving all the importance that the private sector has, because the private sector is mentioned in many risk management issues, but is not involved.

Here, the direction that is being established is that these risk plans are built with the participation of those who are at risk; and the large percentage, in addition to the infrastructure that may have been built by the State, are those who live in the territory and are individuals, families, but all the activities carried out by the private sector.

On the subject of productivity, we have begun to organize a table to see from the productive sector what are the implications of a potential eruption, and the main topic that we bring to the analysis, a connectivity problem in the Metropolitan District, and in the northern part of the country is very large, because mudflows like these can affect all the bridges that are over the Pita, San Pedro and Guayllabamba rivers, causing a total physical separation between the east and west of the city of Quito .

Accessibility, for example, to the airport is in question. The markets of the provinces of Cotopaxi and the south of the Sierra would have to find other ways to reach the city; the markets of the Cayambe area could not reach the markets of Quito due to this lack of connectivity.

The other issue is how to seek from the private sector the necessary preparations to be able to continue activities at a time of uncertainty and impact.

Uncertainty because the orange or red alerts imply suspension of certain activities, but they do not necessarily imply the materialization of the impact, because they may be alerts or alarms that do not finally materialize.

We have already seen how the pandemic greatly affected companies and the worker-employer relationship due to the lack of income; We also learned it in the Tungurahua eruption. So, how to generate the right environment to have legislation or a way of relating between companies and their officials at a time when there is no income, but you have to think that the return to normality has to generate the same income again .

So, a matter of preserving employment, production and provision of goods and consumption, above all, food and health.

What areas of the Metropolitan District could be affected?

We are talking about the drainages of the Pita river, Santa Clara, in the Chillos valley that join, and join with the San Pedro, which comes from the western side of the Pasochoa, continue in the San Pedro until its union with the Machángara and then to the Pisque to form the Guayllabamba and downstream.

All this affected by the lahars would have a very severe impact, total destruction, and the most obvious: the destruction of bridges, the disabling of the Manduriacu dam, the effects on electricity generation in Guangopolo, light poles, transformers.

Advantageously, Quito’s water since 2002, the awareness that was carried out from the National Polytechnic School about the risk was taken over by the Potable Water Company, and finally, as a result of the 2015 eruption, it built bypasses to avoid the risk in the siphons that pass in the conduction of drinking water systems.

Yellow alert declared for the activity of the Cotopaxi volcano

Is a Cotopaxi eruption imminent?

No, it’s not imminent. Cotopaxi is in a sustained state of mild activity, with its ups and downs, showing —as reported by the Geophysical Institute— a slight tendency to be a little more every day or a little more every week, but in reality we see some highs and lowlands that are characterized by a slight emission of ash, and the Geophysicist’s reports show that there are no symptoms of magma injection from the deep areas, which would make us foresee changes in the short, medium term.

However, it is necessary to consider, and very seriously, the eruptive history of Cotopaxi, where the periods of maximum eruptive activity that we know of —by written history—, which are those from 1740, approximately, until 1770 more or less, began like this slowly, but in those 30 years they included large eruptions, but also eruptions of a smaller scale, but also very dangerous ones; and then the period started before 1850, but had from 1854 lava flows until the 1877 eruption, which is our model on which we work the risk, and ended with eruptions still visible at the beginning of the 20th century.

These two great periods began like this. So, in no way can we rule out or minimize the possibility that this, which began in 2015 with clear symptoms in 2002, will not evolve into phases of much more explosive activity.

326 temporary accommodations are already identified in Pichincha, Cotopaxi and Napo due to the Cotopaxi volcano

This 1877 eruption, which is the model you are using, what characteristics did it have?

It was an eruption of what is called “explosiveness index 4″. The index is a measure of the magnitude of the eruptions, and is basically a scale of numbers from 0 to 8, which increases by one order of magnitude with each degree, which means volumes.

Among the incandescent eruptive products that thawed the glaciers and the generation of lahars.

In the lahars that traveled through the northern drainage, in the area of ​​the Pita River, after the San Pedro River, they reached Esmeraldas in 18 hours.

These flows were not only very large and mighty, but they also went at speeds of the order of 30 kilometers per hour; and it is not water, but is made up of very large rocks that are embedded in a mud that has the same consistency as concrete. The chance of surviving those kinds of phenomena is nil, and the chance of resisting that is almost impossible as well.

The clearest example is the case of Armero, in Colombia, in 1985, in an eruption of Nevado del Ruiz where 22,000 people died. (YO)