Japan Warns of Stronger Follow-On Quake Within Week

Japan's meteorological agency issued a tsunami warning following a significant earthquake and placed the country on high alert for a potentially stronger follow-on quake within the next week. The agency's warning reflects established seismic science: large earthquakes frequently precede or trigger secondary events of equal or greater magnitude along the same fault systems, particularly in Japan's tectonically active zones. Authorities framed the risk window as approximately seven days, a standard precautionary horizon used in Japanese disaster preparedness protocols. The warning carries immediate operational weight for coastal communities, emergency services, and infrastructure operators across affected prefectures. Japan's disaster response framework is among the world's most developed, but a secondary quake of greater magnitude would stress evacuation infrastructure, port operations, and supply chains dependent on coastal logistics hubs. Business continuity planning for firms with Japanese manufacturing or distribution exposure warrants review. The next critical signals to watch are aftershock data from seismic monitoring networks and any formal escalation or downgrade of the agency's alert status.