Japan’s been rattled again, with a series of earthquakes shaking things up across the country, especially in Nagano Prefecture. On Friday, April 18, 2025, a 5.0-magnitude quake struck central Nagano, followed by over 40 aftershocks into Saturday, ranging from 2.1 to 4.0 in strength. One local, posting on X from Nagano, said they barely slept through the tremors but was relieved to report no damage in their area. Meanwhile, just weeks earlier, a 6.0-magnitude quake hit Kyushu on April 2, shaking buildings but leaving no casualties or major destruction. These quakes, while unsettling, are feeding into a bigger worry: the growing buzz about a potential “megaquake” that could devastate Japan’s Pacific coast.
The Nagano quake, centered in the northern part of the prefecture, hit around 8:12 p.m. local time on Friday. The Japan Meteorological Agency said it had a maximum intensity of 4 on Japan’s 7-point seismic scale—enough to make chandeliers swing, but not enough to topple homes. No tsunami warnings were issued, and local reports confirmed no immediate injuries or structural damage. Aftershocks kept nerves frayed, with smaller tremors—like a 2.2-magnitude shake at 9:37 a.m. Saturday—popping off regularly. “It’s like the ground’s restless,” one Nagano resident shared online, capturing the unease.
Kyushu’s quake, a few weeks back, was a bit stronger. Striking at 7:34 p.m. on April 2, it clocked in at magnitude 6.0, with its epicenter 30 kilometers deep, about 283 kilometers southeast of Nagasaki. The National Center for Seismology posted on X that it rattled the region but caused no harm, and no tsunami alert was needed. Locals felt the ground sway, but Japan’s bulletproof building codes and quick response systems kept things under control. Still, it was a wake-up call, coming hot on the heels of warnings about a much scarier threat.
That threat is the Nankai Trough, a 600-mile seismic hotspot off Japan’s southern coast where the Philippine Sea Plate grinds under the Eurasian Plate. The Japanese government’s been sounding alarms about a possible magnitude 8–9 megaquake here, with an 80% chance of it hitting within 30 years. A recent report, updated for the first time since 2013, paints a grim picture: up to 298,000 deaths, 2.35 million buildings destroyed, and $1.8 trillion in damage, mostly from tsunami waves as high as 100 feet. Some areas could have just two minutes to brace before the waves crash in. The 2011 Tohoku quake, a magnitude 9 that killed over 15,000, is a haunting reminder of what’s possible.
These recent quakes—Nagano, Kyushu, and others—aren’t directly tied to the Nankai Trough, but they’re stoking fears. A 7.1 quake hit the trough’s western edge last August, prompting Japan’s first-ever megaquake advisory. The Chinese Embassy in Japan even issued a warning to its citizens, urging them to prep for the worst. On X, some users are linking the dots to a prophecy by Ryo Tatsuki, a manga artist who’s called “Japan’s Baba Vanga” for predicting the 1995 Kobe quake and 2011 tsunami. She’s now forecasting a mega-tsunami in July 2025, though scientists say there’s no hard evidence to back her up.
Japan’s not sitting idle. Toyota’s shifting some production out of the at-risk Tokai region to safer spots like Tohoku and Kyushu, and the government’s pushing manufacturers to spread out their supply chains. Earthquake drills are a regular thing—last January, Wakayama Prefecture ran one for a Nankai Trough scenario. Apps like NERV and SafetyTips ping phones with real-time alerts, giving people precious seconds to duck and cover. “It’s about being ready, not scared,” a Tokyo shopkeeper told me through a contact, summing up the vibe.
For now, life goes on. Nagano’s calming down, Kyushu’s back to normal, and tourists are still flocking to Japan’s cherry blossoms and shrines. But the quakes are a reminder of where Japan sits—on the Pacific Ring of Fire, where tectonic plates are always rumbling. “We’re used to it, but you never really get used to it,” one Nagano local posted on X. With the Nankai Trough looming like a storm cloud, Japan’s holding its breath, hoping the next shake isn’t the big one.