The trial of six Italian scientists and a former government official for manslaughter over the 2009 earthquake in L'Aquila has opened in the city.
The 6.3 magnitude quake devastated the city and killed 309 people.
Prosecutors allege the defendants gave a falsely reassuring statement before the quake after studying hundreds of tremors that had shaken the city.
The defence argues that there is no way to predict major earthquakes even in a seismically active area.
The prosecutors accuse the seven of "negligence and imprudence... of having provided an approximate, generic and ineffective assessment of seismic activity risks as well as incomplete, imprecise and contradictory information".
As the trial opened, L'Aquila prosecutor Alfredo Rossini told reporters: "We simply want justice."
The defendants face up to 15 years in jail. Lawyers for civil plaintiffs - who include the local council - are seeking damages of 50m euros (£45m). The civil portion of the case will be heard alongside the criminal case.
Only one of the seven defendants - who include some of Italy's most distinguished geophysicists and members of the country's civil protection agency - was present on the opening day of the trial, which has now been adjourned until 1 October.
"I thought it was important to be here because this is my land, and I also wanted to underline the professionalism and the quality of the other public officials," said Bernardo De Bernardinis, former vice-president of the Civil Protection Agency's technical department.
"I am from Abruzzo and I owe it to the people of this area."
Killed in homes
The seven defendants were members of a government panel, the Serious Risks Commission, tasked with assessing the risks after hundreds of low-level tremors had rattled the medieval city in the months before the earthquake struck.
A week before the quake, they issued a reassuring statement, while also saying that it was not possible to predict whether a stronger quake would occur. They also recommended stricter enforcement of anti-seismic measures, particularly in building construction.
In the minutes of their meeting, held on 31 March 2009, Mr Bosci, the former president of the National Institute of Geophysics, is reported to have told the group that just because a number of small tremors had been observed, it did not mean that a major earthquake was on its way.
Mr Barberi, who headed the Serious Risks Commission, was also reported as concluding that there was "no reason to believe that a series of low-level tremors was a precursor to a larger event".
On the night of the quake, many people remained in their homes and died because of this advice, while others who had decided to remain outside in the street survived, says the BBC's David Willey in Rome.
Vincenzo Vittorini, a doctor who founded the 309 Martyrs association after losing his wife and daughter in the disaster, said: "No-one expected to be told the exact time of the quake. We just wanted to be warned that we were sitting on a bomb."
The case has attracted the attention of the scientific community. Last year, more than 5,000 scientists signed an open letter to Italian President Giorgio Napolitano in support of the defendants.
A lawyer for Mr Eva, Alfredo Biondi, said the trial was not credible.
"This is a trial which opens on very shaky foundations. You cannot put science on trial," he said.