Panic is sweeping across Japan’s eastern coastline as authorities ordered the evacuation of nearly two million people following a tsunami alert triggered by a powerful undersea earthquake in the Pacific.

At least 1.9 million residents have been told to flee to higher ground, with waves up to 3 metres high already crashing into coastal areas from Hokkaido in the north to Wakayama in the south.

In Hokkaido, over 10,000 people were evacuated, with local media footage showing crowds gathering on rooftops and observation towers as sirens blared through the air.

Scenes from Chiba, just south of Tokyo, show people huddled on an observatory deck, anxiously watching the sea. Authorities have repeatedly warned: “Do not wait. Move inland immediately.”

The Japan Meteorological Agency says the tsunami waves could cause widespread flooding, property destruction, and potential loss of life if ignored.

Dozens of waves have already been observed slamming different parts of the Pacific coast, sparking massive power cuts, transport shutdowns, and chaotic scenes in several prefectures.

Emergency services remain on high alert, and coastal access points have been sealed off. The warning zone now stretches hundreds of kilometres, covering vast sections of Japan’s Pacific coastline.