More than 100 aftershocks hit Japan after powerful quake that killed 13

People are being urged to stay alert, with earthquake aftershocks potentially reaching magnitude 7, officials say

An earthquake may be followed by aftershocks. Falling objects, broken glass, and damaged gas or water lines are the highest immediate risks.

This report is based on information from BBC World, monitored by Alert USA's verified emergency feed.

Local impacts may include structural property damage, possible power outages, and road damage, with the added risk of aftershocks in the hours that follow.

Recommended steps: drop, cover, and hold on during shaking; stay clear of windows and heavy objects; expect aftershocks and be ready to repeat; check for gas leaks and structural damage afterward.

Alert USA is tracking this earthquake and will update this report as verified information becomes available.

Verified by Alert USA • BBC WORLD