An abnormal earthquake in Japan

The earthquake in Japan happened suddenly (https://bit.ly/360GVKh),
out of the blue, without any foreshocks (https://bit.ly/3KVQ05A).
So 7.3 points could be a sign of something bigger
(https://bit.ly/3CZ9YKg). The epicenter (https://bit.ly/3ik2Q1v)
was located near the Fukushima atomic station
(https://bit.ly/36r8KuW), so a powerful tsunami is possible.