Weather officials are warning residents in areas hit by Tuesday night's powerful earthquake to remain alert for possible landslides, as it is raining in the region.
The rain started early on Wednesday in Niigata and Yamagata prefectures along the Sea of Japan.
The Meteorological Agency is warning that heavy rains of up to 20 millimeters per hour, accompanied by thunderstorms, are likely in parts of the region until Wednesday night.
They are also warning that the ground may have been loosened by the quake, increasing the likelihood of landslides.
Seismic activity remains high, with 18 aftershocks felt before 11 a.m. on Wednesday. The agency urged local residents to stay on the alert for strong aftershocks for about a week.