Japan is experiencing repeated quakes. Aftershocks are usually lower in frequency than the main quake.

Time (click here)

1. 2016-04-14 12:26:36 (UTC)
2. 2016-04-14 08:26:36 (UTC-04:00) in your timezone

Nearby Places

• 7.0 km (4.3 mi) SW of Ueki, Japan
• 9.0 km (5.6 mi) SE of Tamana, Japan
• 12.0 km (7.5 mi) WNW of Kumamoto-shi, Japan
• 18.0 km (11.2 mi) N of Uto, Japan
• 620.0 km (385.3 mi) SSE of Seoul, South Korea
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• "Birth of Major Strike-Slip Fault" (click here)

There is a subduction zone under southwest Japan. (click here) It has a history of non-volcanic tremors. But, this higher frequency (By frequency I mean severity of the quake) is new. And it these quakes are all coming in between 6 and 6.4 there is movement in that subduction zone.

This is not to be taken lightly for the safety of the people. The quakes could continue. Buildings have already collapsed and there are injuries. 

• April 14, 2016
• By Reuters from USGS

Fresh quake of magnitude 6.4 strikes south west Japan - USGS (click here)

...At around 1503 GMT, another tremor struck the region, according to the USGS. It was initially measured at magnitude 6.4, before being revised down to 5.9. Again, there was no tsunami warning.
After the first tremor, the Nuclear Regulation Authority said there were no irregularities at three nuclear plants on the southernmost island of Kyushu and nearby Shikoku.
Some high-speed trains were halted as a precaution.
Japanese media showed watermelons falling from shelves at a supermarket in Kumamoto.
A quake of magnitude 9 struck offshore north of Tokyo in March 2011, causing tsunami waves along the coast which killed nearly 20,000 people and triggered a meltdown at a nuclear power plant.

Hawaii has an ocean power generator. It is not new. It is proven to provide power to Hawaii.