A powerful 7.5-magnitude earthquake struck off northern Japan injuring more than 20 people and triggering a tsunami in Pacific coast communities, officials said.

The Japanese government said it was still assessing damages from the tsunami and late-evening quake, which struck at about 11.15pm local time in the Pacific Ocean around 80 kilometres (50 miles) off the coast of Aomori, the northern-most prefecture of Japan’s main Honshu island.

“I’ve never experienced such a big shaking,” convenience store owner Nobuo Yamada told the public broadcaster NHK in the Aomori prefecture town of Hachinohe, adding that “luckily” power lines were still operating in his area.

A tsunami of 70 centimetres was measured in Kuji port in Iwate prefecture, just south of Aomori, and tsunami levels of up to 50 c

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