09/28/2021 at 10:08 AM CEST
The Regional Minister for Urban Planning of the Valencian Community, Arcadi Spain, and José Delgado, head of the Seismic Unit of the University of Alicante, have presented the seismic activity map of this autonomous community, which draws the probability of an earthquake occurring in the period analyzed, about 475 years.
The map makes it clear that the entire Valencian Community is an area of seismic danger, but the Vega Baja and the fault that exists between the limits of the provinces of Alicante and Valencia are the most dangerous areas.
Delgado stresses that “we should not be obsessed with the issue that an earthquake is going to occur, even though it is going to happen. In fact, all the earthquakes that have occurred this summer in the province of Alicante are not at all extraordinary and do not differ much from the situation and number of other years.
Delgado stressed that “what has to be taken into account is that, when building, the current technical standard must be fully respected and rigorously applied. The map that we have made reflects the areas where more or less high ground accelerations can occur, according to historical data. The earthquake-resistant standard clearly establishes the criteria. There we must be rigorous as citizens, “said Delgado.
The map is a good complement for technicians when planning constructions. Delgado stressed that it is not above the norm, but it can help. «The map is useful in many ways. To design emergency plans and anti-seismic design. Anything that is implementing measures to improve the response to earthquakes is important, “said Delgado.
For his part, the Minister of Territorial Policy, Public Works and Mobility, Arcadi Spain, said that «this map allows us to better design the instruments of territorial planning, identify the places in the Valencian Community where we should be more careful due to this seismic risk than it is there, to be aware that we live in a territory where this risk exists ».
In addition, he stressed the importance of this cartography to plan the emergency services in a correct and effective way. “In these two essential areas, emergency and planning, collaboration between the Generalitat and the University of Alicante is essential to have this map of seismic risks and to be able to all work with more care and precision”, added Arcadi Spain.
The maps have been incorporated into the autonomous collection of thematic maps CV350 of the ICV. On the one hand, the seismic danger map of the Valencian Community has been made for a return period of 475 years with seismic data obtained from the database of seismogenic zones of the Iberian Peninsula and territories of influence to calculate the danger. seismic in Spain.
On the other, the seismicity and active faults map in the Valencian Community has been designed, with thematic data obtained from the catalog of earthquakes prepared and maintained by the National Geographic Institute and from the QAFI database (Quaternary Active Faults Database of Iberia) .
Torrevieja, 1829: the earthquake that killed almost 500 people
Torrevieja currently has the record for destruction by an earthquake. It was 6.15 p.m. on March 21, 1829, when the earth shook with an intensity of 6.6 degrees on the Richter scale in Vega Baja. The region suffered a great and devastating earthquake. It was Saturday night, and most of the neighbors were caught at home.
They were houses of various heights, without foundations, with little resistant wooden beams and in narrow streets, so that they fell and dragged the neighbors with them. There was no stone on stone in Torrevieja, Guardamar had to be redesigned and Almoradí suffered even more.
In the Vega Baja region 2,965 houses were “devastated”, another 2,396 “ravines”, following the terminology of the time. The damage count was detailed by churches (no less than 30 in «Orihuela y su Partido», two in Almoradí, another two in Formentera & mldr; 47 in total), by bridges (four) or by oil and flour mills (86 and ten respectively).
But the hardest count was that of the dead and wounded: 386 and 375, respectively, in the region; 192 and 150 only in Almoradí, where the greatest damage was recorded.
Hundreds of buildings at risk today
In this sense, about half of the buildings with more than 50 years old built on the seafront in towns such as Alicante, San Juan, El Campello, Elche, Santa Pola, and the rest of the coastal municipalities of the province of Alicante, built in the 60s and 70s of the 20th century, are at risk of harm in case of receiving the impact of an earthquake of magnitude 6 on the Ritcher scale, because in their day they were raised using bad materials, those of the time on the other hand.
A report from the research group on Simulation, Modeling and Testing of Structures of the University of Alicante warns that properties have become vulnerable in the event of an earthquake from six degrees, and the experts demand its revision.
The cause is the deterioration of its concrete structures, some built with bad materials and very subject to erosion caused by the wind and sea salt. What’s more, were built without anti-seismic regulations in force, simply because they were not required. “The buildings are not going to fall, but they need a technical revision”, alerts Salvador Ivorra, professor director of the investigation. Although problems are often found in balconies and overhangs, the pillars on the ground floors are usually the most critical elements.
It is essential that the communities of owners are aware that the real estate must undergo the mandatory technical inspection regulated by the Consell when the building turns 50. There are even municipalities such as Santa Pola, which have already cut the review period to 40 years. The province of Alicante is considered a medium risk area in terms of the possibility of suffering an earthquake and, in fact, earthquakes occur every day, most of them mild, between one and four degrees on the Ritcher scale, but Experts do not rule out that 6-degree Ritcher earthquakes such as the one that shook Torrevieja in 1829 could occur again, leaving almost 400 dead.
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