Many buildings in Lorca that were at first thought to have suffered severe structural damage are not in as bad a shape as originally thought, government authorities said Thursday. But 10 percent of the buildings inspected by engineers do have structural damage, according to Lorca Mayor Francisco Jódar. The Popular Party leader didn't say whether he would be suggesting that residents return to their homes.
On Wednesday, soon after the two quakes hit, authorities feared that as many as 80 percent of the buildings in the Murcian city were now unsafe. A team of experts from the Andalusian Geophysics Institute warned that some buildings may still be susceptible because they were constructed on ground that could be considered unstable.
Jesús Ibáñez, the director of the institute, said quakes in this region often produce a resonance effect underneath the earth. He explained that Lorca is sitting on a bed of gravel and sand, which tends to amplify the tremors and produces this effect.
"That's where the damage may be," he said.
However, Ibáñez went on to say that it is still too early to determine if there was any threat of movements of loose earth in the future. The director also declined to comment on whether there could be any aftershocks, "because we don't know for sure."
In the future, new building codes should take into consideration the unstable ground below Lorca, Ibáñez said.
The city is located near a fault line that is called Alhama, or Lorca-Totana by some, and is one of the most active in Spain, according to Luis Suárez, the president of the Spanish Association of Geologists.
The line is located on the southern edge of the Eurasian tectonic plate, where it meets with the African plate.
According to Suárez, the Eurasian plate moves about four millimeters a year and can produce earthquakes on occasion.
Suárez also said that, with just two exceptions, all the buildings in Lorca appear to "have stood up" to the tremors. "The problems were with the falling debris and bricks from the buildings," he said.
Geologists and engineers are expected to continue to study the earth and the structures in the coming days.
Deputy Prime Minister Alfredo Pérez Rubalcaba has asked Defense Minister Carme Chacón to coordinate earthquake relief efforts.