Honshu, Japan was just hit with its third earthquake of the day as 177 relatively significant earthquakes have peppered the Western Pacific Countries. The last 5.0 temblors hit approximately 4:20 p.m. Tuesday, December 18, 2012, local time. According to the USGS, the quake had a depth of 20 miles and struck off the east coast of Honshu, Japan.
The nominative rule of thumb for seismologists is that an earthquake's largest aftershock will be one magnitude smaller than the main shock, hence with this quake registering a couple of points higher than two earlier seismic temblors geologist believe it to be a new event.
These same geologist believe a 7.9-magnitude earthquake could hit the region with the next year.
The last big Japanese earthquake ruptured near the boundary between the Pacific and North American tectonic plates, moving slabs of the Earth's crust. The quake was a megathrust earthquake, where the Pacific plate dove underneath Japan at the Japan Trench. The seafloor was pushed away from Japan sending waves roaring toward HawaiiJapan Just Hit With Third Earthquake Today as 177 Earthquakes Have Peppered the Western Pacific and the West Coast of the United States
link to guardianlv.com