Following the indictment in June 2010, six Italian seismologists (and a couple of bureaucrats) are being tried on charges of manslaughter. Nature has a report on a recent hearing in an Italian court: New twists in Italian seismology trial.
The hearing also included some true scientific debate when Lalliana Mualchin, former chief seismologist for the Department of Transportation in California, testified as an expert witness for the prosecution. In 2010, when news about the indictment broke, Mualchin was among the few experts who openly criticized — and refused to sign — a letter supporting the indicted seismologists signed by about 5,000 international scientists.
The problem is in part a scientific one, Mualchin said. The Italian scientists based their analysis on the frequency of earthquakes in the area. This is known as the probabilistic seismic-hazard analysis (PSHA), a method that is state of the art in many countries, but that, in Mualchin’s view, systematically underestimates seismic hazard because it does not consider extreme and rare events.
“Frequency is not important, what really matters is the largest earthquake we can expect, the strongest one that has happened in the past. Risk prevention should be based on that,” he said. This is the philosophy behind deterministic seismic-hazard analysis, a method that Mualchin says has been mostly abandoned by the scientific community, to the point that younger seismologists do not even learn about it.