A magnitude 8.2 earthquake struck off Russia's eastern coast on Friday, briefly prompting a tsunami scare but causing no casualties or substantial damage, Russian emergency authorities said.
The USGS says the quake was actually magnitude 8.3.
The epicentre of the quake was located at a depth of 385 miles (620 km) in the Sea of Okhotsk, 244 miles (390 km) west of the nearest city, Petropavlovsk-Kamchatsky, the U.S. Geological Survey said.
How big is a magnitude 8.2 quake, compared to say, a magnitude 5.8 quake?
The magnitude scale is really comparing amplitudes of waves on a seismogram, not the strength (energy) of the quakes. So, a magnitude 8.2 is 251 times bigger than a 5.8 quake as measured on seismograms, but the 8.2 quake is about 3,981 times stronger than the 5.8, according to the US Geological Survey.
The USGS says:
This quake was felt in Petropavlovsk-Kamchatsky, the main city on the Kamchatka peninsula and home to a nuclear submarine base, and on Sakhalin island, where Russia's largest liquefied natural gas project is located.
Regional emergency authorities issued a tsunami warning for Sakhalin and the Kurile islands, advising residents of dangerous areas to seek high ground, but lifted the warning several minutes later.
Residents of northern Japan felt the quake but there was no tsunami warning from Japan's meteorological agency. (Editing by Elizabeth Piper)