A small tsunami, with waves reaching 50 centimeters (20 inches), struck the remote Japanese island of Hachijojima on Tuesday. This followed a 5.6-magnitude earthquake that hit near the Izu Islands chain, located south of Tokyo. The Japan Meteorological Agency (JMA) issued a tsunami alert for the region after the earthquake, which occurred at a shallow depth of 11.7 kilometers (seven miles) according to the United States Geological Survey.
The tsunami waves reached Hachijojima around 9 am (0000 GMT), roughly 45 minutes after the earthquake. A smaller tsunami, measuring 10 centimeters, was also observed on Miyakejima Island. Around 25,000 people reside on the small Pacific islands south of Tokyo. While some residents reported not feeling the earthquake, there have been no immediate reports of damage.
The JMA warned that slight changes to the ocean surface may be observed along Japan’s vast Pacific coastline, stretching from Chiba near Tokyo to Okinawa near Taiwan. Japan, situated on four major tectonic plates, experiences around 1,500 earthquakes annually, most of which are minor. Thanks to advanced building techniques and well-rehearsed emergency procedures, the impact of even larger tremors is usually contained.
However, a potential mega-quake, with an estimated magnitude of 8-9, has a 70 percent probability of striking within the next 30 years, according to the Japanese government. Experts warn that such an event could affect a large swath of the Pacific coastline and threaten an estimated 300,000 lives in the worst-case scenario.
The fear of a catastrophic event is rooted in Japan’s history, notably the 2011 undersea earthquake that triggered a devastating tsunami. The 9.0-magnitude quake left around 18,500 people dead or missing and sent three reactors into meltdown at the Fukushima nuclear plant, resulting in Japan’s worst post-war disaster and the most serious nuclear accident since Chernobyl.
