If so, what would it be? Work accident? or alternative nuke test site undergoing a calibration test?
First question would be location in regards to the suspected site where Japan believes a test is soon to occur. Unfortunately I'm not feeling well enough yet to try to figure the geography out. If this is in the area, then the second question needs to be asked, why so many explosions, as indicated in the article. If not mining, or demolition then possible calibration testing. If it is in the area where it is suspected that a test (when it happens) will take place, then I'd lean towards calibration testing.