Online rumors claim Japan's Kumamoto quake was artificially induced

After the 7.1 magnitude tremor in Kumamoto, social media posts alleging a man-made origin spread widely, while scientists dismissed the idea as infeasible.

Following the deadly 7.1 magnitude earthquake that struck Kumamoto Prefecture on July 28, a user on X claimed the seismic wave was produced by an explosion, a post that attracted around 3 million views. Monitoring of Japanese-language posts about an "artificial earthquake" revealed a sharp rise in mentions, reaching roughly 10 000 on the day of the disaster and continuing to climb the following day. The Seismological Society of Japan, which added a FAQ entry in March, described the notion of a man-made quake as unrealistic, citing the 16-kilometre depth of the event and the immense cost and difficulty of drilling a hole 10 kilometres or deeper.

The society also pointed out that the technology needed for a deep underground nuclear explosion has not been developed, noting the Kola Superdeep Borehole as the deepest ever at about 12.3 km after two decades of work. The Japan Fact-check Center said false claims are propagated both by believers and by those aware they are false, driven in part by social-media reward mechanisms. Disaster-psychology professor Reo Kimura said people often gravitate toward simple explanations in stressful situations.