Noises and “hums” in Grazalema and seismic exercise in Malaga: what is occurring within the underground of Andalusia in the course of the storm | Science | EUROtoday

The successive storms which can be hitting Andalusia, with persistent rainfall and robust storms in areas not used to downpours, have brought on uncommon phenomena, reminiscent of a hydrogeological flood – the water from the aquifer rises to the upper components – within the space of ​​Grazalema (Cádiz), which retains residents in suspense. With the subsoil overflowing with water, residents of the areas most affected by the storm have warned of noises and “strange hums” coming from the bottom. And, coinciding with the looks of a phenomenon of seismic exercise within the south of Andalusia, some consultants counsel that hydroseisms may very well be occurring, that are seismic actions induced by water exercise within the subsoil.

There are hydrogeology consultants on the bottom within the areas most affected by the storm and investigations are additionally being strengthened in areas with seismic exercise, however, for now, the National Seismic Network guidelines out that hydroseisms are occurring. “The National Seismic Network does not have contrasted scientific evidence that allows us to affirm that recent rains have generated or influenced these earthquakes. Therefore, in no case has it called them hydroseisms,” writes the National Geographic Institute on networks.

This is what is thought—and what’s not identified—about what is occurring underground in some Andalusian municipalities hit by the storm.

Where have these “hums” been heard on earth?

It has been advised by neighbors of Grazalema, a Cadiz city of 1,500 inhabitants that stands on an aquifer. “Strange humming noises sounded from the ground, like someone banging against a wall,” a neighbor advised this newspaper. With the aquifer stuffed by the rains of current weeks, water flowed wherever it may, by the flooring and even by the partitions of the homes. The city has been evacuated because of the threat of earth actions that might destroy streets or properties.

What are these unusual noises and tremors coming from underground?

As Nahúm Méndez, geologist and scientific communicator, defined to EL PAÍS, the precise trigger isn’t identified. “We have several theories and we are probably seeing several overlapping phenomena,” stated the skilled.

On the one hand, he indicated, “the very movement of water across the surface, in its friction against the ground, and with all the things that water carries (rocks and sediments), can generate noise and vibration in the closest environments.” It may additionally be that inside the aquifer itself, “the movement of the water together with the movement of the air that may be inside, may generate bubbles that hit the walls, burst and generate noises and vibrations.”

And on the identical time, he added, native actions, of small magnitude, also can happen as a result of “when there is such a large volume of water at play, the rocks suffer an increase in pressure inside, these rocks can fracture and that generates a release of energy” that the residents of the realm discover as a vibration.

Is there seismic exercise within the areas affected by the storm?

As reported by the National Geographic Institute, since February 3, the National Seismic Network has recorded a collection of small magnitude earthquakes within the southeast of the province of Malaga, about 30 kilometers deep. The final one, of magnitude 3, was reported this Saturday morning in Gaucín, a municipality within the Serranía de Ronda area.

As confirmed to EL PAÍS by the director of the National Seismic Network, Juan Vicente Cantavella, the looks of earthquakes on this space “is not surprising.” These collection, he identified, happen once in a while and “are not worrying.” However, he indicated, they’ve put in extra seismic stations within the space to develop their analysis into the origin of the detected earthquakes.

Are hydroseisms occurring?

Cantavella has assured that there isn’t any scientific proof that enables us to affirm that the current rains have generated or influenced these earthquakes. That is why they can’t be referred to as hydroseisms.

“There is some confusion between earthquakes and other hydrological phenomena,” Cantavella has superior. The skilled defined that, with the rains, the subsoil is stuffed with water and phenomena associated to this case can happen, reminiscent of landslides or different hydrogeological occasions. But that has nothing to do, no less than with the data they’ve proper now, with the earthquakes not too long ago recorded in some areas of the south of Cádiz and Málaga.

“People see the coincidence of water accumulation and earthquakes and interpret a cause-effect. But we have no evidence that water has facilitated the concurrence of these earthquakes. In fact, since they are such deep seismic movements [se han registrado a 30 kilómetros de profundidad]would make us think the opposite, that they have nothing to do with it,” he clarifies.