Japan’s government has issued a rare “megaquake advisory” after a 7.5 magnitude earthquake struck off the country’s northern coast on Tuesday, warning that a much larger offshore quake could generate a towering tsunami in the coming days.

The 7.6-magnitude quake struck in waters off Aomori Prefecture on Japan’s main island, Honshu. It triggered a tsunami warning, which was later lifted.

Japan ’s weather agency has issued its highest-level warning that a megaquake could follow Monday’s 7.5-magnitude tremor. Authorities urged anyone living near the Pacific coast to remain vigilant throughout the coming week and to prepare evacuation plans in case they need to flee their homes.

The Japanese government is on the alert because a larger follow-up earthquake may occur in the area. Read more at straitstimes.com. Read more at straitstimes.com.