Great Quake North of Japan

A great quake struck north of Japan overnight, New Zealand time. The magnitude 8 earthquake struck at a shallow depth in the Kuril Islands, 1600 km northeast of Tokyo.

The magnitude 8.3 earthquake struck at a depth of 29 km at 14 minutes past midnight on November 16th 2006 New Zealand Daylight Time, on the boundary between the Pacific and Okhotsk tectonic plates.

The epicentre of the quake was 440 km ENE of Kuril’sk, Kuril Islands, 1650 km northeast of Tokyo, Japan and 7185 km northeast of Moscow, Russia.

The have been no reports of casualties or damage from the quake which struck at 10:14 p.m. local time.

The Pacific Tsunami Warning Centre issued a tsunami warning but withdrew the alert at 3:58 a.m. NZDT when wave buoy data reported a low-level tsunami in Japanese and Alaskan waters. The wave generated was 30 cm high at the wave buoy at Hanasaki, Hokkaido, Japan at 1:43 a.m. NZDT.

Seismologists refer to 8th magnitude earthquakes as “great quakes.” This morning’s quake occurred within 80 km of the Kuril Trench which defines the collision zone between the Pacific and Okhotsk plates, where the Pacific plate subducts (slides under) the Okhotsk plate.

It was the largest earthquake to occur in the area since 1915. A magnitude 8.5 quake struck the southern Kuril Islands in 1963, and a magnitude 9 earthquake occurred further north off the coast of Kamchatka in 1952.

Aftershock activity in the Kuril Islands has been occurring at a steady rate since this morning’s event. Fifteen earthquakes of magnitude 5 or 6 have struck the Kuril Islands or places nearby up until 7 a.m. NZDT as the plate boundary reacts to stress changes in the area. If the aftershock sequence follows typical patterns, a quake of magnitude 7 or more can be expected in the area at some stage.

[Compiled from data supplied by the US Geological Survey and its contributing agencies.]

Leave a Reply