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Authorities in Japan are urging people to avoid hoarding as anxiety over a possible megaquake triggered a spike Saturday in demand for disaster kits and daily necessities.
In its first such advisory, the weather agency said a huge earthquake was more likely in the aftermath of a magnitude 7.1 jolt in the south on Thursday which left 14 people injured.
At a Tokyo supermarket on Saturday, a sign apologized to customers for shortages of certain products it attributed to "quake-related media reports."
"Potential sales restrictions are on the way," the sign said, adding that bottled water was already being rationed due to "unstable" procurement.
On Saturday morning the website of Japanese e-commerce giant Rakuten showed portable toilets, preserved food and bottled water topping the list of the most sought-after items.
In Tokyo, some residents were ramping up their disaster preparedness.
Bar employee Kokoro Takeuchi said she had ordered bottled water online following Thursday's tremor.
"I'm very worried," the 27-year-old told AFP.
"The bar I work at is underground so if a quake happens all of a sudden, there's a good chance we might not be able to escape. So I've been trying to figure out how best to evacuate," she said.
But others were more resigned to the inevitability of the megaquake.
"I am worried of course, but overthinking about it will get you nowhere," company worker Mika Nakagawa, 34, told AFP.
"If it happens, then that's that," she said.
Some retailers along the Pacific coastline also reported similar disaster-related supplies in high demand, according to local media reports.
The advisory concerns the Nankai Trough "subduction zone" between two tectonic plates in the Pacific Ocean, where massive earthquakes have hit in the past.
It has been the site of destructive quakes of magnitude 8 or 9 every century or two, with the central government previously estimating the next big one would strike over the next 30 years roughly with a 70% probability.
Experts, however, emphasize the risk, while elevated, is still low, and the agriculture and fisheries ministry urged people "to refrain from excessively hoarding goods."
A magnitude 5.3 tremor rocked the Kanagawa region near Tokyo Friday, triggering emergency alarms on mobile phones and briefly suspending bullet train operations.
Most seismologists believe the Friday jolt had no direct link to the Nankai Trough megaquake, citing distance.