The defendants were accused of giving "inexact, incomplete and contradictory information" about whether small tremors felt by L'Aquila residents in the weeks and months before the April 6, 2009, quake should have been grounds for a warning.
The 6.3-magnitude temblor killed 308 people in and around the medieval town and forced survivors to live in tent camps for months.
Many much smaller tremors had rattled the area in the previous months, causing frightened people to wonder if they should evacuate.
"I consider myself innocent before God and men," said another convicted defendant, Bernardo De Bernardinis, a former official of the national Civil Protection Agency.
Prosecutors had sought convictions and four-year sentences during the trial. They argued that the L'Aquila disaster was tantamount to "monumental negligence," and cited the devastation wrought in 2005 when levees failed to protect New Orleans during Hurricane Katrina.
Relatives of some who perished in the 2009 quake said justice had been done. Ilaria Carosi, sister of one of the victims, told Italian state TV that public officials must be held responsible "for taking their job lightly."
The world's largest multidisciplinary science society, the American Association for the Advancement of Science, condemned the charges, verdict and sentencing as a complete misunderstanding about the science behind earthquake probabilities.
There are swarms of seismic activity regularly in Italy and most do not end up causing dangerous earthquakes, said geologist Brooks Hanson, deputy editor of the organization's Science magazine. He said that if seismologists had to warn of a quake with every series of tremors, there would be too many false alarms and panic.
"With earthquakes we just don't know," Hanson said Monday. "We just don't know how a swarm will proceed."
Quake scientist Maria Beatrice Magnani, who followed the trial closely and knows the defendants professionally, called the outcome "pretty shocking."