A blog post [0] about a month ago explains better why they are on trial: The prosecution’s closing arguments [...] made it clear that the scientists are not accused of failing to predict the earthquake. “Even six-year old kids know that earthquakes can not be predicted,” he said. “The goal of the meeting was very different: the scientists were supposed to evaluate whether the seismic sequence could be considered a pr…
What you quote says: 1. "They were not accused of failing to predict the earthquake" 2. "whether the seismic sequence could be considered a precursor event"
But I'm no expert, so I'll be grateful if someone with the knowledge could clarify.