April 6, 2012 | 2
In the early morning of April 6, 2009 a 20 seconds lasting earthquake with magnitude 6,9 (followed later by weaker aftershocks) occurred near the city of L´Aquila (Abruzzo, Italy).
More than 45 towns were affected, 308 people killed, 1.600 injured and more then 65.000 inhabitants were forced to leave their homes.
Italy has a long and tragic history of earthquakes. The position between two large continental plates (the European and African) and various micro-plates of the Mediterranean Sea results in highly active seismicity all over the peninsula.
The first map of seismicity of the Mediterranean area and an extensive research on earthquakes in Italy was published in 1857 by the Irish engineer – and self educated geologist – Robert Mallet under the title “Great Neapolitan Earthquake- The First Principles of Observational Seismology“. Mallet got interested in earthquakes in 1830 by a drawing in a natural sciences book, displaying two stone columns twisted by an earthquake in Calabria. He decided to study the forces able to do this to human constructions. In his work he noted that damages on buildings were distributed in distinct areas, setting out from a point of heaviest destruction. These points, the epicentre of an earthquake, were not randomly distributed, but found in “seismic belts” following the Apennine Mountains.
Earthquakes mark the history of the area surrounding L’Aquila and the province of Abruzzo. Historic events or swarms of trembles are recorded for 1315, 1349, 1452, 1461, 1498, 1501, 1646, 1703, 1706, 1791, 1809, 1848 and 1887. One of the most important earthquakes occurred February 2, 1703, causing devastation across much of central Italy and destroying the city of L’Aquila, killing 5.000 people.
The destruction caused by the earthquake of 2009 surprised experts and generated discussions about the anti-seismic building standards adopted in Italy. While most of the medieval structures in rural areas collapsed or were heavily damaged, in L’Aquila most concern arouse from the observation that modern buildings suffered the greatest damage and that the death toll included mostly young people. L’Aquila was a university town and cheap accommodations which suffered severe damage were inhabited by students, also many students died when a dormitory at the University of L’Aquila collapsed. Even some buildings, believed to be “earthquake-proof”, collapsed, like parts of the new hospital and various buildings of the government.
Fig.1. The local prefecture damaged by the earthquake, emblem of the situation in Italy, image from Wikipedia-User TheWiz83 May 7, 2009.
In rural areas the “core” of most of the historic buildings consisted of local material, like stone, superimposed by cement constructions or supplementary floors of recent age. It was this mismatch that caused the collapse of these buildings. In L’Aquila the earthquake of 1703 destroyed most of the older buildings. During reconstruction work first “anti-seismic standards” were introduced – the rebuild houses possessed thicker walls, improved joints between floors and the allowed height of the building was limited.
Many “modern” buildings of the city in contrast were build previously of 1984, before modern anti-seismic buildings standards were introduced in Italy.
However there was and still is a widespread disregard of building standards and the ignorance by people and (in part corrupt) authorities of the seismic hazards. Many concrete elements of the collapsed buildings (like the hospital) “seemed to have been made poorly, possibly with sand“, a common tactic to build fast and cheap by building enterprises controlled by criminal organisations.
The earthquake of L’Aquila was therefore only in part a natural disaster and the manmade catastrophe was strongly misused by Italian politics and many promises made shortly after the earthquake are still unrealized today.
Most alarming were the legal repercussions of the earthquake on science. Based on a general lack of understanding of science by the public and authorities various persons were accused (“Scientists on trial: At fault?” Nature September 14, 2011) to have ignored “premonitory signs” of the earthquake - in form of pseudoscientific claims of dubious veracity and “warnings” mostly published by individuals in the internet.
TERTULLIANI, A. (2011): Il segni del terremoto sul tessuto urbano. DARWIN No. 42 Marzo/Aprile: 80-83
WALKER, B. (1982): Earthquake. Planet Earth. Time Life Books: 154