What do the seismic swarms that are taking place in the vicinity of Teide mean?
In recent years, in Tenerife we have seen several similar swarms in the same area and at the same depths. They may be related to the island’s own activity. We believe it is related to the complex system that sleeps under the island. We have a magma chamber under Teide and probably a more intricate system throughout the island.
What do we know about this phenomenon?
Tenerife is an island where we have not seen instrumented volcanic activity and we do not know how seismicity behaves before an eruption. But in principle they are very small earthquakes, which are very close together and of a similar magnitude. All this seems to indicate that it is not a moving magma, because if it were, it would have to generate a lot of seismicity and at different magnitudes. We have theories, although it is difficult to specify. What we do know is that if an eruption is going to happen, we should see different signals.
Is it possible that there will be an eruption on Teide in the short term?
There is nothing to say it. This activity is small and we do not see other types of activities, such as a clear emission of gases or a deformation. And this is what we expect to find when a volcanic eruption occurs, as it happened in La Palma or El Hierro. It is impossible to know if an eruption will occur in a year’s time. The odds are not that they are high, but they cannot be ruled out. Determining when it will happen well in advance is impossible. Among other things, because we don’t know how much magma is down there. The techniques that have been applied to understand Tenerife’s subsoil are also unable to determine if it has the strength to come out. It is one of the great challenges of volcanology, both here and in the rest of the world. That said, we don’t see any forerunner signs in the short term, but we don’t have a crystal ball to know when that will happen.
If an eruption occurs, would it be on Teide itself or could it occur elsewhere on the island?
It is impossible to specify. As far as we know, the probability that the next eruption will occur on Teide is lower than that it will be basaltic or monogenetic, that is, in another place on the island. We know that Teide’s last eruption was relatively quiet about 1,000 years ago. 2,000 years ago there was a more explosive one. Between the two there have been some more explosive eruptions, but many others were basaltic, such as those of Chinyero, Fasnia, Arafo or Siete Fuentes. There are geologists who say that there is a direct relationship between basaltic eruptions and the Teide magmatic chamber. With which, a phenomenon of recharge of the magmatic chamber can be confused with an eruption phenomenon in another place.
How many years have there been eruptions in Tenerife?
Historical records show that an eruption occurred in the 15th century, which is probably Boca Cangrejo, since it coincides with that time. Then we went 200 years without any eruption, until the period between 1704 and 1706 when four eruptions were described, although there are those who describe it as only one. Then one occurred in 1798 and the next in 1909. On average, in the last 500 years, Tenerife has erupted once every hundred years. That is why people might think that the next one is already here, but we must bear in mind that there have been periods of 200 years without an eruption. We would have to have more data and the dating of previous eruptions cannot be done with much precision.
What values will let us know that the Teide-Pico Viejo system is awakening?
There is no specific number of anomalous values, it depends on each system. One would expect to find anomalous values of seismicity, deformation and gases. But there are not many systems in the world like the one we have here, in which two types of eruptions can occur. Therefore, it is difficult to buy it with other places.
