A powerful earthquake struck off the coast of eastern Honshu on Thursday, prompting Japanese authorities to issue a tsunami warning.
According to the Japan Meteorological Agency (JMA), the quake occurred at around 4:53 p.m. local time off the coast of Sanriku (39.8 degrees north latitude, 143.2 degrees east longitude), approximately 10 kilometers beneath the seafloor. The magnitude was initially reported at 7.4 before being revised upward to 7.5.
The JMA issued tsunami warnings for the coast of Iwate Prefecture and the central Pacific coast of Hokkaido following the quake.
"Tsunami waves of up to 3 meters are expected," the agency said, urging residents in the affected areas to "evacuate immediately."
The JMA also issued tsunami advisories for coastal areas from Hokkaido to Fukushima Prefecture.
NHK reported that tsunami waves were observed along some stretches of coastline. The earthquake registered a shaking intensity of "upper 5" on the Japanese seismic scale in parts of Aomori Prefecture.
In Japan, earthquakes are measured using both "magnitude," an absolute measure of the quake's size, and "shindo," a scale representing the relative intensity of shaking in different regions.
On the Japanese shindo scale (0 to 7), an "upper 5" indicates shaking strong enough to hinder most people's movement and potentially topple unsecured furniture.
