Lunchtime, and time for another jolt! This one was a bit unusual, a 3.8 under the Ariake Sea just off of Mt. Kimpo. I suspect it was on the Tatsuda fault. That fault worries me a bit; apparently it is capable of an M6 or greater and essentially runs under downtown. - William
http://www.jma.go.jp/en/quake/6/20160901114917495-011146.html