They are reporting that the earthquake here in Shizuoka is unrelated to the earthquake and aftershocks in northern Japan.
In other words this earthquake happened independently of the previous earthquakes.
According to current reports (as of 00:15 16th), this is based off the differences in location and nature of the two quakes.
There is still the possibility of aftershocks and power outages. People in the area, please be wary, but certainly no need to panic. I think it would be good to get some rest too. Praying that everyone is unhurt and safe.