Arab News Japan

TOKYO: An earthquake measuring 6.2 on the Richter Scale rattled buildings on Japan’s northern island of Hokkaido on Wednesday morning even though the epicenter of the quake was closer to eastern Russia.

The quake struck in the Sea of Japan about 200 km east of Russia’s far eastern city of Vladivostok and 600 km west of Hokkaido’s main city of Sapporo. 

It had a seismic intensity of 3 in Hokkaido in a phenomenon called an “abnormal seismic area” as it was centered 480 km deep and strong shaking was felt far from the epicenter.

Despite the size of the quake, there was no danger of a tsunami, according to Japan’s Metrological Agency.

In the case of a “deep earthquake” with a very deep epicenter such as this, there is often no tremor near the actual epicenter.

In the case of an “abnormal seismic zone,” the distribution of seismic intensity differs greatly from normal earthquakes. 

Data of the weather agency said that when an earthquake occurs deep in a subducted oceanic plate, there is a layer above that that easily attenuates seismic waves, so the tremors are smaller directly above the epicenter. Seismic waves tend to travel through the interior of the oceanic plate without being attenuated much, so tremors are greater at locations far from the epicenter.