When the earth trembled in Assisi 10 years ago, toppling frescoed sections of the vault of the Basilica of St. Francis, the world took notice. Yet earthquakes are common in Italy. In the last year alone 491 events registered 2.5 or higher on the Richter scale, meaning they could be felt, even if they did not necessarily cause damage.

Now Italy’s Culture Ministry has implemented guidelines that it hopes will mitigate the threat that earthquakes pose to the country’s artistic heritage.

“Italy’s patrimony has been lost because we used to intervene after the fact and not before,” said Roberto Cecchi, general director of the Architectural Heritage and Landscape Department, which is responsible for the safekeeping of Italy’s monuments.

Under the new guidelines unveiled this summer, officials at the local and national levels are to evaluate the seismic risk to individual structures in their jurisdictions and take steps to reduce the vulnerability. These steps could include using steel chains to join the walls together, or employing carbon fiber strips in the walls and the vaulting as a sort of flexible bandage.

“The idea is to see a structure as a sort of box that is more resistant if the vertical and the horizontal elements work together,” said Laura Moro, an architect at the Culture Ministry. “In a seismic area sooner or later something will happen. The problem is that for years this issue was totally ignored.”

The residents of this town on the shore of Lake Garda — in northern Italy, between Venice and Milan — realized that a minute before midnight on Nov. 24, 2004, when an earthquake registering 5.2 damaged hundreds of buildings. Since then Mauro Biasin, an architect, has been overseeing the restoration of nearly 300 damaged churches and monasteries. Many are still closed and carry signs saying, “Closed because of earthquake damage.” There were no deaths, but Mr. Biasin points out that had it struck exactly one month later, the churches would have been filled for Christmas Eve.

The church of Santa Margherita di Scozia in Carpeneda di Vobarno above Lake Garda was built in 1949, just a few years before anti-earthquake construction regulations went into effect. The 2004 earthquake detached the facade and opened gaping cracks on the triumphal arch as well as minor cracks above the windows. It also loosened and rotated beams, Mr. Biasin said. The restoration consisted of joining all the various elements of the building — walls, apses and roof — using steel tie-rods and trusses. The damaged frescoes were restored by the original painter. The church was reinaugurated in June.

The buildings that Mr. Biasin has restored in the last three years are about to become textbook cases for the initiative, because his work was directed by the study group that developed the guidelines. Steered by information from the group, Mr. Biasin’s restorations eschewed reinforced concrete, a material commonly used in the past because it had been found seismically resistant in contemporary structures.

The project will be a good case study, Mr. Biasin said in an interview in his office in Brescia. “The calculations say this will work. I just hope I don’t live long enough to experience the next major earthquake to see if they actually do.”

Sergio Lagomarsino, a professor of structural engineering at the University of Genoa who helped create the working group, said, “Great faith used to be placed in reinforced concrete.” But it is now known that concrete doesn’t interact well with traditional masonry; it’s not flexible enough, and its salts have been known to ruin stonework. Interventions in concrete, were “often invasive,” he said.

Seismic improvements and strengthening interventions like inserting tie-rods or adding upper stringcourses, or horizontal bands, to the masonry can be designed case by case to meet specific weaknesses. “Every building is different, so no rule will apply to all,” said Carlo Blasi, a professor of architectural restoration at the University of Parma.

This means that for each historical building, the seismic history of the region and the vulnerability of the structure is examined, and its cultural significance is taken into account in determining its vulnerability.

“The key thing is that a building doesn’t collapse during an earthquake,” Ms. Moro said. “But if the building is culturally important — having, say, a significant fresco — then making sure it doesn’t collapse isn’t enough. You have to limit the damages too.”

Money to cover the evaluation and eventual strengthening of a structure are drawn mostly from existing budgets, depending on who owns the building. Many government institutions and private entities already set aside money for monitoring a building’s state of health. “Seismic safety has to become a criterion for all interventions,” said Ms. Moro, who coordinates a database of the state of conservation and the seismic risk to individual cultural buildings. “The problem is getting people to set limited funds aside for something that can’t be predicted, like an earthquake.”

The Culture Ministry and the Civil Protection Agency report that more than 64 percent of Italy — more than 3,000 municipalities — faces a medium to high risk of serious damage from an earthquake. In all about 500,000 buildings in Italy, many of them private, will have to be examined.

Compared to other earthquake-sensitive areas like California or Japan, “the damage in Italy can be potentially higher because older buildings are more vulnerable,” said Mauro Dolce, director of the department in the Civil Protection Agency that assesses seismic risk. Culturally significant historic buildings are also under special surveillance because many house hospitals, schools and other public institutions.

Experts believe that preventive action, including seismic retrofitting, can reduce future costs to the state. After an earthquake devastated parts of southern Italy in October 2002, killing 27 schoolchildren, rental fees for scaffolding topped 5.2 million euros, more than $7 million. That is “about a fifth of what the state is spending to restore the Uffizi and double the exhibition space,” the Culture Ministry noted.

“In the last 25 years more than 75 billion euros have been spent in post-seismic reconstruction, not to mention the loss of lives that could have been avoided,” Mr. Cecchi said, adding that preventive measures “would have cost a fraction of that.”

Yet the experts have no illusions. “No building can ever be safe, so we’re really talking about an objective to reach that will be determined in any case by the available resources,” said Michele Calvi, an engineer at the University of Pavia specializing in seismic design. “The guidelines are just a start.”

Applying them may also uncover other, existing structural problems. “It’s like an old woman who falls and breaks her leg,” Mr. Biasin said. “She’s still going to have a variety of ailments caused by her age.”

September 4, 2007