[winoneforthegipper]

These prefectures are located inside a very large graben. Most quakes inside this feature have been very deep not nearly as shallow as this swarm.

Secondly, those quakes that were shallow could be attributed to the regions volcanics, which includes the MT ASO caldera which is a hot spot that rivals Iceland's and our very own Yellowstone.

The fact that there is lineal migration to the north certainly makes me think something other than tectonic.

[Red Badger]

Magma chamber filling up...........................

[Red Badger]

Mount Aso volcano erupts following violent earthquake streak in Japan (VIDEO)

https://www.rt.com/news/339788-japan-volcano-eruption-quakes/

[WMarshal]

For those like me who don’t know the term “graben”:

In geology, a graben is a depressed block of land bordered by parallel faults.