Japan’s Meteorological Agency withdrew a magnitude 9.9 earthquake warning just eight minutes after issuing it following a quake near Russia’s Kamchatka Peninsula. The agency apologised and launched an investigation into the error.

There is no upper limit on the magnitude of an earthquake, but it depends on the length of a faultline. Japan sits on Pacific Ring Of Fire, a zone of active faultlines that witnesses the maximum number of earthquakes.

Japan mistakenly issued a magnitude 9.9 earthquake alert near the Kuril Islands before correcting it to a 6.9 quake near Kamchatka. JMA apologises for the error.

Authorities have downgraded a tsunami warning in northeast Japan after a major earthquake sparked calls for residents to evacuate to higher ground. Waves up to 80cm high were recorded shortly after the quake — which has been revised up to a magnitude 7.7 — rumbled 100km off the coast of Sanriku, at a depth of 20km, just before 5pm local time.

An emergency alert warning of a magnitude 9.9 earthquake turned an otherwise ordinary afternoon in Japan into several minutes of anxiety on Friday, as phones rang across the country and people braced for powerful shaking that never came.

The JMA issued an emergency warning after initial automated data suggested a magnitude 9.9 earthquake near the Kuril Islands.

A powerful 7.6-magnitude earthquake struck late Monday off northern Japan, triggering a tsunami of up to 70 centimeters (27 inches) in Pacific coast communities and warnings of potentially higher surges,

The Japan Trench is basically Mount Everest turned upside down. Running offshore of northeastern Japan, the trench marks the boundary where the Pacific Plate dives beneath the plate carrying Japan. Scientific drilling has reached water depths exceeding 8,