Why Russia's megathrust earthquake was among biggest ever recorded, but damage was minimal
The magnitude-8.8 earthquake was the largest since 2011, when a magnitude-9.1 tremor and subsequent tsunami struck off the coast of Japan and killed more than 15,000 people.
Wednesday's earthquake, known as the Kamchatka earthquake, is considered a megathrust earthquake — common to each of the planet's largest recorded quakes.
These plates slowly shift around — moving a few centimetres every year — and often get stuck against each other due to friction.
Stephen Hicks, an environmental seismology expert at University College London, said megathrust earthquakes "cause some of the world's largest ruptures and trans-ocean tsunamis".
Megathrust quakes often cause tsunamis because the faults they cause tend to come to, or even directly penetrate, the sea floor, Dr Hicks said.
How much of the sea floor moves influences whether a tsunami is formed, and how big it might become, added Lisa McNeill, a tectonics professor at the University of Southampton.
