Lawsuits after the eruption of Mt Ontake

This news isn’t about new volcanic activity in Japan but rather the results of one of the most tragic volcanic events in the last few years. In September 2014, Ontake had a surprising phreatic (or phreatomagmatic) explosion. There was little in the way of clear signs that such a blast was going to occur beyond some volcanic earthquakes that started in the week before the eruption. Ontake is a very popular hiking destination, so many people were on the volcano when the eruption occurred and at least 54 people died as a result of the eruption.

Now, families of some of the victims are suing the local government over the eruption, claiming that they downplayed the threat posed by the volcano and that it was inadequately monitored (only three of five seismometers were working at the time). This is a little bit like the trial of the Italian geologists after the L’Aquila earthquake, where they were blamed for the deaths due to the earthquakes because they downplayed the risk.

The big problem is that geologists monitoring volcanoes or assessing earthquake hazards only have pieces of data from which to work, so making claims without a firm backing can be as bad. If geologists lose credibility because of too many “false positives” about an eruption, then getting people to leave when a real crisis arises can become nearly impossible. The volcanologists from the Japan Meteorological Agency (JMA) worked with the data in hand and determined no apparent threat in Ontake’s behavior. This ended up being incorrect, but not really due to misinterpreting the data that was being collected, however imperfect.

Is the local government (geologists) really to be blamed for the deaths or was it a unavoidable accident?