Kiwi scientists join petition over quake trial

GNS scientists and earthquake experts are among several New Zealand seismologists who have signed a petition supporting their Italian colleagues, who are on trial for allegedly failing to warn residents about a deadly quake.

GNS seismologist John Ristau said he and his colleagues had signed a petition supporting the seven scientists and other experts who have been charged with manslaughter.

About 5200 international researchers have signed the petition.

The Italian scientists and experts are accused of giving "inexact, incomplete and contradictory information" on whether small tremors felt by L'Aquila residents in the six months before the April 6, 2009, magnitude-6.3 quake should have constituted grounds for a quake warning.

The defendants are facing manslaughter charges after 308 people were killed in the quake.

The scientists and their international colleagues say there is no way of predicting a quake.

"It's impossible to predict earthquakes, so it doesn't seem right to charge them for failing to predict anything when there is nothing they can predict," Ristau said.

He said he signed the petition "to basically say this is ridiculous".

Large earthquakes were expected in areas of high seismic activity, such as Fiordland, Ristau said, and no-one could have predicted the magnitude-7.1 quake in Christchurch on September 4 last year.

"There was nothing unusual in the Canterbury region leading up to the Darfield quake - it was pretty quiet,'' he said.

"Usually in areas of high seismic activity you'd expect there to be a large earthquake, so we wouldn't have expected a large earthquake on the Canterbury Plains."

Earthquake statistician David Rhoades said he felt it was unjust to '' prosecute scientists for failing to predict an event that was unpredictable by any scientific method''.

''In my opinion, the most scientists can do is to estimate the probability of an earthquake occurring in a given space-time-magnitude window,'' he said.

"Giving any kind of warning or advice to the public of what to do in the light of such information is the proper responsibility of government authorities, and not of their scientific advisers.''

Canterbury University geological science lecturer Mark Quigley said the ''holy grail'', a way for scientists to predict the specific location, depth, time and magnitude of an earthquake, did not exist.

''One could say that the chance of a major earthquake may increase during a seismic swarm, [but] history dictates that more often than not major earthquakes do not follow these events, and [the] probability of delivering a 'false alarm' and causing undue panic would have been quite high,'' he said.

''To me, this highlights the importance of effective science communication. While it is important to provide the public with probabilistic earthquake 'forecasts', it is equally important to contextualize these assessments.''


Victoria University geophysics professor Martha Savage said the case showed there was a big gap between what scientists could deliver and ''what the local population and politicians want us to be able to deliver''.

She said the situation was not helped by non-scientists who claimed to be able to "predict" earthquakes.  

''It is quite difficult to know what to tell people when there is an earthquake,'' she said.

"My own research has shown that in general in New Zealand, when a moderate earthquake occurs (that is not already part of an aftershock sequence), there is about a one-in-20 possibility that another one of the same size or larger will happen within the next few days.

"That possibility gets lower quickly and the likelihood of big earthquakes is still small (less than one in 100 that an earthquake a whole magnitude larger will happen in that same time period).  Yet the possibility of a big earthquake is quite a lot (100s to 1000 times higher depending on how you count it) than it was just before the earthquake."

Savage said people should use such quakes as a warning to check their supplies and be sure their homes were quake-proofed.

"I had a few people tell me after the September 4 Darfield earthquake that I should have given people more reassurance that they didn't want to hear about further risks; they wanted to feel safe. Certainly after the February earthquakes I was happy that I didn't respond to that pressure,'' she said.

"Apparently one of the non-scientists attending the meeting in L'Aquila, Italy, falsely stated to the population that moderate earthquakes decrease the risk of big events. I think he was responding to similar pressures.  And 99 times out of 100, no large earthquake would follow the small ones.

"I think that he was incorrect but he may also have believed it himself. People want to believe that things will get better. So he was wrong, but I don't think that his behaviour was criminal in any sense of the word.

"If the public decide to make scientists accountable through fines or jail terms for their announcements regarding natural-hazard risks, the scientists will respond by not saying anything, and possibly by moving their research into areas where they are not as likely to encounter such uncertainty. Therefore, the public will lose out."


Victoria University professor of geophysics Euan Smith can sympathise with the Italian scientists on trial for manslaughter - he was sent a kettle by the Auckland Star for ''getting into hot water'' over the 1987 Edgecumbe quake.

In 1987, Smith was acting superintendent of the Seismological Observatory when an earthquake swarm started on February 21 near Maketu, in the central Bay of Plenty.

On March 2, after a few days of activity, Smith issued a press release ''saying that there was no reason to expect that the earthquakes would lead to a bigger one, but that earthquakes were likely to be ongoing and residents should take sensible precautions''.

While the release was aired by the media that day the magnitude-6.5 Edgecumbe quake struck.

''I was somewhat derided in the media. The Auckland Star sent me an electric kettle for getting into hot water,'' he said.

''It might have been much worse for me if there had been heavy casualties, but there weren't. Of course, no-one wanted to read the disclaimer and so the main lesson that I took from these events is that extreme caution is required in such circumstances.

''I thought I had covered off the possibility of something larger happening, but the media didn't.''


- The Press and Stuff