Japan issues megaquake advisory for north after 7.5 quake, urges readiness

• Japan issued a megaquake advisory after a 7.5 magnitude earthquake struck off Aomori and Hokkaido.
• The advisory is a wake-up call for a potential magnitude 8 or larger quake, not a prediction.
• There is an increased risk of a subsequent M8+ quake within the next week, particularly in Hokkaido and Sanriku.
• A megaquake in the Hokkaido-Sanriku area could cause a 30-meter tsunami and significant devastation.
• Officials urge residents to be prepared with emergency bags and evacuation plans, while remaining calm.

Why It Matters: Japan's advisory signals a heightened risk of a devastating megaquake, urging preparedness.