This is how the La Palma volcano is monitored: seismic arrays, thermography, sulfur meters and “long nights”

They take a huge amount of scientific data that is collected 24 hours a day, and more so now that the La Palma volcano has erupted. From seismographs to thermal images, passing through sulfur dioxide emission detectors. All the data are few and used to control and follow the activity in real time.

Of course, the methods with which they work today have nothing to do with the field expeditions that were required in the past and that, at times, endangered geologists. Field work continues and is very important, but technology has made it possible to do everything much more agile, efficient and secure.

David Calvo, geologist in charge of communication at INVOLCAN, explained to OMICRONO last April how cutting-edge technology helps keep an eye on volcanoes canaries. Focusing especially on Mount Teide, as the most important and active in the entire archipelago.

How to watch a volcano

Technological advance has not displaced instrumentation in situ. These devices located on volcanoes and in areas close to eruptions remain a primary source of data to work with. Among them, in INVOLCAN they have “equipment that measures the gases emitted by the volcano and through them we can know if it is more or less active, “explains Calvo.

A higher emission of sulfur dioxide may indicate that the volcano is more active and cause more problems in the future. For this they use spectrometers capable of identifying the characteristic gases of volcanoes. Although they are placed “in the crater of Teide with portable equipment and we check the levels of gases and temperature “, others, on the other hand, remain installed both in fixed stations that send information autonomously, as well as mobile measurements are being made on the ground to know in real time how the volcano of The Palm.

The other branch of study in situ goes through geophysics. In this case, “we have seismic stations composed of seismographs that record volcano earthquakes, “explained Calvo. These equipment are really sensitive and capture even the slightest seismic movement. It is reported promptly for study as it may be a sign of increasing volcanic activity to monitor.

On Saturday the INVOLCAN team deployed a seismic array in the El Charco area to monitor the Cumbre Vieja volcano. This is a set of seismic stations that are installed at a short distance between them that “in addition to detecting seismic waves, allows establishing the direction from which these waves come”, key data to detect with more sensitivity any seismic signal coming from the interior of the volcano. .

“They are especially useful machines on the ground because they warn of any movement, no matter how subtle,” explained Calvo. That is why during the last days the INVOLCAN team has continued to update and strengthening instrumentation on La Palma, placing seismic stations through the key points of the island.

When the volcano is active, another of the measurements made on the ground is perhaps the most obvious: checking how hot the earth is. To do this, it is done both through thermal images of the eruptive column and taking thermography measurements on roads and mount in full eruption. “All the data serve to understand what the volcano is telling us,” they explain from the institute.

In the last hours these measurements on the ground are the ones that allow to move with greater agility, although David Calvo pointed out in his day to the loss of instruments at times when an eruption occurs. But the truth is that this closeness makes the measurements as faithful as possible and that las decisions made are appropriate to the magnitude of the volcano.

Satellites and artificial intelligence

Beyond field work, one of the main improvements that this type of real-time volcano tracking work has experienced is the possibility of having a wide variety of satellites to ensure a reliable source of information even if the situation becomes difficult.

Accuracy is everything when tracking a volcano. It is an almost millimeter work and here technology is essential. “We have a combination of measurements on the ground and in space using GPS. We install a device on the flanks of the volcano, or wherever we are interested, and we measure the position of that instrument using GPS. We are talking about a few centimeters of deformation indicating that the volcano can erupt, “explained Calvo, so the margin of error of their machines is one millimeter horizontally and one centimeter vertically.

Globally satellites are also being used for volcanic monitoring. “Specific Sentinel and Themis satellites are used for natural disaster monitoring”. Images that allow a good follow-up easier and more comfortable than in the past, since it is possible to follow up before and after and thus see the alterations.

In addition to photography, satellites can also perform topographic measurements to observe surface changes after any of these natural catastrophes. “Today there are devices that are capable of measuring gas concentrations of a certain chemical compound such as sulfur dioxide from space.”

These satellites are so sensitive that they can track eruptive columns (volcanic plumes) throughout the world. For example, the eruption in April of the La Soufriere volcano in Saint Vincent and the Grenadines (the Caribbean) ended up reaching the Canary Islands, so it is interesting to know where the sulfur dioxide of La Palma, a gas responsible for the acid rain and “one of the most representative in volcanic surveillance”.

But the potential of satellites for tracking volcanic activity has only just begun, especially if the interest is in tracking active but hard-to-reach areas. “The space race has made things much easier for us in everything related to monitoring volcanoes in remote places. The constellations will provide Internet connection to everyone, included in isolated areas where mobile coverage does not allow measurements on the ground “, explained Calvo.

As an example, the INVOLCAN communication manager made reference to places in the world where the only reports we have come from satellites, which makes monitoring difficult. “This happens a lot in the Aleutian Islands or in Kamchatka, where we learn about eruptions from satellites.”

24 hour surveillance

Collecting such an amount of data is not valid if it is not managed properly. From the Volcanological Institute of the Canary Islands, they recognized that they are being “Long nights”. And it is that, although machine learning projects are being created, with the aim that a server or a computer learn to interpret seismic signals, the location and monitoring in recent days is being done manually. There is always a professional watching.

The seismologists continue working to understand what the volcano is telling us. pic.twitter.com/WQM4cFw2Uh

— INVOLCAN (@involcan) September 19, 2021

“The surveillance stations are broadcasting 24 hours a day and if the situation requires it we deploy emergency teams capable of analyzing the situation throughout the day. “ In a normal operation, in the event that no volcanic activity is detected, there is a team that performs the analysis work during normal hours.

When you have many stations, the amount of data received daily is immense when complex seismic movements such as swarms or eruptions that have occurred in recent days are recorded. To do this, “they have developed software so that learn to process signals and do it almost better than humans “and help interpret what the volcano means.

Even so, the professionals of the Institute still have a period of intense activity to monitor and Instantly monitor how the La Palma volcano moves. Although yes, they insist that the population “sage always the instructions of the local authorities and do not go near the place of the eruption “.

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