Earthquake shook northern Japan

A strong earthquake shook northern Japan on Wednesday evening, and a small tsunami was forecast for part of its Pacific coast. A tsunami of about a half-meter was forecast for Hokkaido island s central and eastern Pacific coast, and for Aomori and Iwate prefectures. Iwate prefecture, or state, was heavily damaged by last year s earthquake and tsunami. Thousands of aftershocks have shaken the region since then, nearly all of them of minor or moderate strength. The epicenter was about 146 miles (235 kilometers) south of Kushiro, Japan, on Hokkaido island. It was a relatively shallow 16 miles (26 kilometers) below the ocean floor. The quake was not felt in Tokyo, more than 450 miles (730 kilometers) away. The Pacific Tsunami Warning Center in Hawaii said there was no threat of a Pacific-wide wave.