An earthquake in the vicinity of the Russian Far Eastern city of Petropavlovsk-Kamchatsky can be expected in the coming days, say scientists.
The major earthquake was 866km (538 miles) northeast of Yakutsk, capital of the Sakha Republic - also known as Yakutia.
Epicentre was in mountains of Kamchatka peninsula with a powerful 7.3 magnitude.
Scientists are puzzling to explain the tremor, 8.3 on the Richter scale, by far the largest since records began.
The quake could be a world record for a tremor caused with involvement by humans, it is claimed.
Epicentre in Republic of Khakassia, but tremors were felt over a wide area including Krasnoyarsk city.
A series of tremors in recent days measuring 4.7 to 6.4 points on the Richter scale have been registered east of Petropavlovsk-Kamchatsky.
The 5.3 tremor was felt over a wide area but was centred some 21km from Belovo in Kemerovo region.
Epicentre of quake measuring up to 6 on Richter Scale was under Lake Baikal - but local pets knew it was coming.
Dozens of major tremors recorded this year as scientists monitor 'unusually strong seismic activity' that will one day tear continent in half.