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Antonio Aretxabala, Geologist , School of Architecture

Seismic amnesia

Fri, 01 Jun 2012 15:20:02 +0000 Published in ABC and Vocento newspapers

Sadly it was confirmed yesterday: the lifeless body of the victim issue 17 trapped in the rubble of the last earthquake has been found. Six died on the 20th and the others on the 29th. The aftershocks at an average of one every hour exceed a hundred, some of them greater than 5 Degrees magnitude. The Italian seismic-resistant construction rule of 2004 no longer counted on the seismogenic character of these faults dormant for 450 years. The seismic report of the people of Emilia Romagna has suffered an amnesia of four centuries and tremendous human, social, economic and patrimonial consequences. Ferrara (World Heritage Site) is the first modern city in Europe, designed urbanistically already in the fourteenth century, counted on what was then a well-known phenomenon. The more we know about these new Italian earthquakes in their scientific aspect, the more they resemble the 2011 Lorca earthquake, and less like the 2009 l'Aquila earthquake.

Active Spanish faults are implicit in our seismic-resistant rule (NCSE02). Those we consider inactive are not. The first ones would affect a total of 2618 localities located in areas with seismic risk, in 724 are agglomerated more than 5000 inhabitants, a population of more than 20 million people. We know almost nothing about the latter. However, despite the fact that Spain is a seismic country, there is no historical awareness of seismic risk and its importance, either in the elite sector or at a scientific level with a certain popular projection, or in universities. The long time that has passed, almost 130 years, since the catastrophic earthquake of Andalusia in 1884 with nearly 1200 deaths and destruction that reached Degree X, has also shaped our seismic amnesia.

During this time we have tripled, we have gone from about 16 million people living mainly in a rural and immobile environment, to 47 million predominantly urban and high mobility. This is where the greatest danger lies, and much more so now than before. We have the best weapons to get away with earthquakes, but they are in storage; the advanced land law of 2008 is still tucked away in the drawers of the autonomous regions, although almost no one understands it, it is amnesia. The general population would not know how to react in the event of an earthquake, let alone know the most seismic areas of the country itself, the busiest ones.

Likewise, the more specialized or cultivated population believes that engineers and leaders are the ones in charge of mitigating disasters by complying with and enforcing increasingly refined seismic-resistant standards. Engineers also believe that they are the ones designated to lead us to that end by applying theoretical postulates that nature always overcomes, on the object of their programs of study: the buildings and their Structures, that is to say, the pieces of the system. But the real seismic scenario of the 21st century is the city. Seismic-resistant construction standards have not been, are not and will never be sufficient. Spanish cities have been designed with urban planning laws inspired in the 20th century for everything (including any individual or speculative interest subject ) except for anti-seismic design criteria. The reality is that the history of Spain, saving this lapse of 130 years just at the entrance of modernity, in the last seven centuries, is replete with examples of destructive earthquakes with intensities above VIII on the Mercalli scale (above 5 to 6 on the Richter scale), "earth tremors" and what to do if they erupted, were subjects of study in schools and universities until a hundred years ago. The culture of seismicity is a phenomenon that has not been updated as other aspects of the country.

The seismic amnesia of the population, media and leaders, seems to dominate over the sporadic outbreaks of interest when something like Lorca or Ferrara awakens our curiosity, makes us reflect and the bars of the country are filled with expert geologists, architects and engineers. Then it subsides and we go to sleep again.