Portugal Earthquake: Clues to quake also felt in Spain

Many people woke up today in southern Spain, especially in Huelva, to feel tremors under their beds. Others did not notice the tremors, but were surprised when all the phones in the house started ringing. It was the Android alert system of the National Geographic Institute (IGN), warning of a earthquake in Portugal who was also able to feel both in Spain and Morocco.

The earthquake had its own center in the Atlanticbut very close to Lisbon. For now, although many Portuguese say they have felt it, it does not appear that any serious damage has been done to be regretted. At least, none has been made public.

This is not the first earthquake in Portugal. It is a territory with several geological faults, that’s why the floor often shakes. But what are the characteristics of this earthquake and how does it differ from other earthquakes of similar strength?

Main characteristics of earthquakes in Portugal

The earthquake in Portugal struck at 06:11 a.m. Although early warnings suggested a magnitude greater than 6 and a depth of 28 kilometers, the latest reports from IGN indicate that it actually occurred. magnitude 5.5 and a depth of 19 kilometers.

This makes him earthquake of medium strength and shallow depthfor being below 70 kilometers. Fortunately, the fact that it was superficial did not make it serious, as happened, for example, with the earthquake that hit Lorca, Murcia, in 2011. it is much more chaos.

What does moderate value mean?

An earthquake is said to have a moderate magnitude when it is between 5 and 6. In this case, although the first reports indicated it as higher, it ultimately appears that the earthquake in Portugal had magnitude 5.5.

Earthquakes in this range are usually strong enough to be felt by people and even wake them up if they are sleeping. It can also cause damage to some buildings, but usually only if they have weak structures.

Returning to the example of the Lorca earthquake, this description may seem inaccurate if we consider that it had a magnitude of 5.1 and yet much of the city’s buildings had to be rebuilt. The main reason is that the Lorca earthquake was particularly shallow, with a depth of less than 2 kilometersIn addition, it had a very specific direction, and all its seismic waves were collected in one place.

Another earthquake in Portugal

This is not the first time Portugal has experienced an earthquake. In fact, it is very small compared to what shook the city of Lisbon in 1755.. It is estimated that on the current scale its magnitude would have been between 8.7 and 9, which is extremely high. In fact, they died from 60,000 to 100,000 people.

At that time, not all the technologies that exist today for measuring earthquakes and determining their origins existed. Therefore, it is not known exactly where its center was. It is believed that at some point Atlanticlike the last earthquake in Portugal. But it is clear that the failure must have been more serious. So what is failure?

It is defined as a crack in the ground where two blocks have slipped past each other. The friction between these edges is what causes the earthquake. Therefore, the larger the fault, the greater the intensity of the earthquake, because more friction is created.

These faults are usually located at the junction of lithospheric plates. In the case of the southern coast of the country where the earthquake occurred in Portugal, The Eurasian and Nubian plates are joiningThere are many known faults out there in the ocean. But also on land, where earthquakes can be even more destructive.

On the other hand, the proximity of several faults can lead to very strong earthquakes. This is believed to be what happened in the 18th century. Whether it was a single fault or a combination of several, the overall dimensions would have been approximately 200 km long and 80 km wide.. The good news is that this only happens occasionally. Today’s quake must have been caused by a much smaller fault, and fortunately there doesn’t appear to have been any serious damage to report. We’ll stay vigilant. For now, this is what we know about the Portugal quake.