A Japanese parliamentary panel is due to release - as early as this week - the results of its in investigation into the Fukushima Daiichi nuclear disaster. The report could point to what many experts have already asserted was the cause: the magnitude 9.0 earthquake. Despite denials by the government and TEPCO, a number of seismologists and other experts have suggested the earthquake and not the tsunami caused the meltdowns. Fumiya Tanabe, a former senior researcher at the government's Japan Atomic Energy Agency, conducted his own analysis of data released by the government and Tepco, and concluded that reactor No. 2's cooling facility, called a suppression chamber, was likely seriously damaged by the earthquake, possibly releasing radioactive substances. If that were the case, all other reactors of similar design—11 of which are still in use in Japan— "would come under close scrutiny," Mr. Tanabe said. Concerns have already been raised about the two Oi reactors approved for restart that, seismologists say, could be situated on an active fault line. An estimated 150,000 people demonstrated outside Prime Minister Noda's residence on Friday. Oi unit 3 was restarted on Sunday.