A massive undersea earthquake Friday in Russia's Far East prompted a tsunami warning and unleashed tremors across Russia including in Moscow around 7,000 kilometres away, but caused no casualties or damage.
The US Geological Survey (USGS) estimated the quake at 8.3 magnitude and placed its epicentre in the Sea of Okhotsk off the shore of the Kamchatka Peninsula at a depth of more than 600 kilometres (370 miles).
Russia issued a tsunami warning for Sakhalin island and its region, prompting residents to leave their homes for higher ground. But the warning was lifted minutes later, with no casualties.
"I was sitting at my work desk and it started shaking like this," a young woman from Sakhalin island said in televised remarks, rocking her arms. "It was scary to be honest."
"I don't know what it was, but my sofa shook a bit," an elderly woman added in remarks broadcast on Rossiya 24 television.
The quake was felt most strongly in the city of Petropavlovsk-Kamchatsky, around 560 kilometres away, but there were no casualties or damage, the emergency situations ministry said.
"It shook for a long time and it was quite scary. The walls were rocking and the chandelier shaking," one elderly woman resident told Channel One television.
"Parked cars moved back and forward a few centimetres," a young man told the channel.
The huge magnitude and great depth of the quake meant that its echoes were felt across the Eurasian continent including in the Russian capital itself.
"The whole plate -- on which the continent stands -- shook," Anatoly Tsygankov of the state Rosgidromet environmental monitoring service told AFP.
"And this movement of the continental plate was felt all over Russia -- not just in Moscow, we received calls from Nizhny Novgorod and other cities."
Aftershocks were also recorded in the Siberian regions of Krasnoyarsk, Tomsk and Novosibirsk, the emergency situations ministry said.
In Moscow, which is eight time zones away from the region hit by the quake, "the earthquake was felt on the top floors of high-rise buildings," the emergency situations ministry said.
It received reports of chandeliers swinging and water in aquariums shaking as a result of the quake, a ministry spokesman said.
In central Moscow, staff of an insurance company were evacuated for an hour after some saw furniture move and windows shaking, Russian media reported.
"We were sitting in the office and felt that it was shaking very strongly. We joked that it was like an elephant had moved in," one member of staff, Ksenia Kruglova, told the Life News website.
Several other office buildings in Moscow were briefly evacuated, witnesses wrote on Twitter, posting photographs of people huddled on the street.
The emergency ministry even opened a hotline number to calm shaken Muscovites.
Experts said that the last time Moscow felt serious tremors was in 1977 as a result of a major earthquake in Romania.
In the northwestern city of Saint Petersburg, a 22-storey office building was evacuated after the people working there felt the building shaking, the local emergency situations ministry said, although it was not clear if the quake was the cause.
The waves from such a quake travel long distances deep beneath Earth's surface, said Alexei Lyubushin, chief researcher at the Institute of Physics of the Earth at the Russian Academy of Sciences.
"If an earthquake happens at such a low depth, the waves move along low layers, practically the mantle," he told Kommersant FM radio.
"The waves can even move through the Earth's core," he added.
There have been four major earthquakes with a similar epicentre since 1988 but because of their great depth they have not caused damage, the USGS said.
A second, smaller earthquake struck off Russia's eastern coast Friday evening, the US Geological Survey said.
The new, magnitude 6.8 quake was registered at a depth of 623 kilometres (387 miles) in the Sea of Okhotsk, the USGS said.
A spokeswoman for the Russian emergencies ministry, Irina Rossius, told AFP that Russian officials had registered throughout Friday a total of four aftershocks measuring between 4.5 and 5.0 magnitude at a depth of around 600 kilometres.
There were no reports of casualties or damage.