Warnings for a tsunami as high as 3m have been issued for the Japanese coastline after a powerful 7.4-magnitude earthquake struck off the northeastern coast.
The earthquake struck off the Sanriku coast at 4.53pm local time, with its epicentre located at latitude 39.8 north and longitude 143.2 east, according to the Japan Meteorological Agency (JMA). The epicentre of the earthquake was located around 100km east of the coastal city of Miyako in Iwate prefecture.
The massive quake occurred at a depth of about 10km and had a preliminary magnitude of 7.4. However, earlier, the European Mediterranean Seismological Centre said the magnitude was 7.3.
First tsunami waves have reportedly begun reaching Iwate prefecture, with a wave of up to 40 cm recorded at Miyako port. A tsunami has been detected about 50km off the coast of Aomori, in northern Japan’s main island, according to the public broadcaster NHK.
The seismic intensity was recorded as upper 5 on Japan’s seismic scale, which goes up to 7. According to the scale, upper 5 indicates that “most people find it difficult to walk without holding on to a stable object” and that “unfixed furniture may fall over”.
An upper 5 was recorded in Aomori prefecture on Japan’s seismic intensity scale, and lower 5 levels were recorded in Iwate and Miyagi prefectures, the agency said.
Japan uses a special shindo scale to describe how strongly the ground shakes during an earthquake. It goes from 0 to 7 and reflects the actual impact felt at a location, unlike magnitude which measures the earthquake’s overall energy at its source.
The JMA warned of a tsunami of up to 3 metres in Iwate prefecture and parts of Hokkaido. Warnings are also in place in Aomori, and tsunami advisories are in effect across wider coastal areas, including Miyagi and Fukushima. People along these coastal regions have been asked to evacuate.
Japan is positioned along the infamous “Pacific Ring of Fire” where the Pacific, North American, Eurasian, and Filipino tectonic plates converge. The constant shifting of the four plates leads to frequent earthquakes in the East Asian country, some of which can be devastating.
Japan is known for its world-leading earthquake preparedness, with resilient building structures adhering to strict regulations and regular earthquake drills in schools.
The country was struck by a major earthquake in March 2011, starting a tsunami that killed over 18,000 people and sending three of the Fukushima nuclear power plant’s reactors into meltdown. It’s still recovering from that nuclear disaster.
