Nature
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A 7.7 magnitude earthquake has been reported off the coast of northern Japan, the country’s Meteorological Agency has announced, leading to tsunami advisories in the region.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.The earthquake occurred off the coast of Sanriku (sometimes Rikushū), on the northeastern side of the island of Honshu, at around 4:53 pm local time. This event took place at a depth of around 20 kilometers (12.4 miles).
According to Japan’s NHK World, an 80-centimeter (3-foot) tsunami has already struck Kuji Port in Iwate Prefecture, and the water is rising. The Meteorological Agency has warned that the Prefecture and parts of Hokkaido and Aomori could experience waves as high as 3 meters (10 feet).
.png "A map showing Japan and the affected areas on its northeastern coast. The majority of the area has been highlighted in yellow while some of the smaller islands to the south have blue hightlights. There is a red X off the coast showing the quake's epicenter. To the right of the map is a box explaining the size of the earthquake and when it happened. To the bottom right is a key showing what the color highlights mean, including yellow meaning \"tsunami advisory\".")
Japan’s prime minster, Sanae Takaichi, has urged residents in the affected coastal areas to evacuate until the advisories (downgraded from previous tsunami warnings) have ended. They have been advised to seek higher ground while the tsunami threat remains in place.
Bullet train services in Aomori have also been halted because of the tremors, Kyodo news agency has said. The Yamagata Shinkansen has also halted services between Tokyo and Fukushima stations, while the Akita Shinkansen service has also been suspended between Tokyo and Morioka stations.
Airports in Shin-chitose and Sendai say their operations have not been affected by this earthquake.
The Tokyo Electric Power Company has confirmed that there are no abnormalities at the Fukushima Daiichi and Fukushima Daini nuclear power plants. Nor are there any reported issues that the Higashidori nuclear power plant in Aomori Prefecture or the Onagawa plant in Miyagi prefecture, the Tohoku Electric Company has explained.
Australia’s Joint Australian Tsunami Warning Centre (JATWC), part of the Bureau of Meteorology, has issued a statement that there is “no tsunami threat” to the country at this time.
It has now been 15 years since Japan was struck by the magnitude 9.0 earthquake caused a 15-meter (49-foot) tsunami that killed around 20,000 people. The Great East Japan Earthquake, as it is now known, also hit the Fukushima Daiichi nuclear power plant, flooding the power plant’s generators and causing total power loss and the meltdown of three reactors.
Japan uses a unique seismic intensity scale that measures earthquakes based on the actual shaking of the ground and its impacts at specific locations. This scale, which is set to 0-7, differs from others that just focus on the total energy being released at the quake’s epicenter. As a consequence, this approach is more precise, allowing Japan’s authorities to assess potential damage with more accuracy. At time of writing, this quake was rated at upper 5 on the seismic intensity scale.
The country experiences more frequent earthquakes because it is located on the “Pacific Ring of Fire”, a junction of four major tectonic plates that are constantly moving and interacting. When these plates collide or subduct, they cause significant seismic stress that results in earthquakes in the region.
Japan’s authorities have warned that this latest quake will likely be followed by others of a similar size over the coming weeks, but they have also stated that there is a small (1 percent) chance that it will lead to a “mega-quake”.
