Don't forget that the Sendai nuclear power plant is operational on the island of Kyushu, and while Japanese officials claim that there have been no problems at the site since the quakes hit, who knows for sure?

Aftershock forecasts halted
The Yomiuri Shimbun
Apr 21, 2016
http://bit.ly/1VI0B8A

The Japan Meteorological Agency has stopped announcing the probability of aftershocks in Kumamoto Prefecture because past occurrences are not providing the guide they did before, according to an agency official.

The decision to stop announcing estimates is unusual, since the JMA has always released probabilities, with the exception of earthquake swarms.

Aftershock probabilities are usually calculated based on data compiled from past cases, like those indicating the downward trend in the frequency of aftershocks. The JMA would typically make announcements such as, “Over the next three days, there is a probability of aftershocks measuring lower 5 or higher on the Japanese seismic intensity scale of 7.”

After a magnitude-6.5 quake jolted the region at 9:26 p.m. on April 14, the JMA released one announcement that there was a 20 percent probability of aftershocks measuring lower 6 or higher. Afterward, however, the main quake struck at 1:25 a.m. Saturday, measuring 7 on the intensity scale and with a magnitude of 7.3.

Seismic activity subsequently spread to Kumamoto Prefecture’s Aso region as well as Oita Prefecture. The JMA has not released any aftershock estimates since.