Our directory of things of interest

University Directory

Largest deep earthquake puzzles scientists

  • Written by  Harley Rustad
  • Published in Tectonics
The Sea of Okhotsk The Sea of Okhotsk Shutterstock
01 Nov
2013
The strongest deep earthquake ever recorded has puzzled seismologists, as it occurred deeper than was previously thought possible

The magnitude 8.3 earthquake took place 609 kilometres beneath the Sea of Okhotsk between the Kamchatka Peninsula and mainland Russia. It was thought that the extreme pressure at such depths would inhibit the type of rapid fault rupture that caused the quake.

Researchers from the University of California, Santa Cruz compared the quake to the previous largest known deep quake, which took place 637 kilometres beneath Bolivia in 1994. At four kilometres per second, the fault rupture in the Okhotsk quake was much faster than other deep earthquakes.

The researchers suggested that the scale and speed of the Okhotsk event was related to the fact that the subducted Pacific plate is much colder than the subducted slab involved in the Bolivian earthquake. Fluid often acts as a fault lubricant, but at this depth, the pressure should have squeezed the fluid from the slab.

‘If the fault slips just a little, the friction could melt the rock and that could provide the fluid, so you would get a runaway thermal effect. But you still have to get it to start sliding,’ said Thorne Lay, one of the study’s co-authors. ‘Some transformation of mineral forms might give the initial kick, but we can’t directly detect that. We can only say that it looks a lot like a shallow event.’

This story was published in the November 2013 edition of Geographical Magazine

Related items

NEVER MISS A STORY - Follow Geographical on Social

Want to stay up to date with breaking Geographical stories? Join the thousands following us on Twitter, Facebook and Instagram and stay informed about the world.

More articles in NATURE...

Climate

A report details how tropical storms are fuelling the rise…

Wildlife

After years of trials, talks, tweaks and test runs, EarthRanger…

Climate

Nationalism might gain political points in certain parts of the…

Geophoto

With guaranteed sunshine, bright blue skies and not a hint…

Oceans

A review of coral-saving methods is helping communities decide which…

Polar

A seven-year study of Patagonia’s ice sheets has revealed the…

Climate

The environmental impact of Bitcoin is higher than its virtual…

Geophoto

With a camera in everyone’s pocket, the once rarified world…

Climate

The idea of the Earth as a self-regulating, living organism…

Oceans

A temporary fishing ban has been imposed by the European…

Wildlife

A look at the contribution of hippos to the savannah…

Wildlife

The new app encourages young children to connect with the…

Energy

A type of panel has been invented that can generate…

Tectonics

In the 4th century BC, Aristotle proposed that earthquakes were…

Climate

The Chartered Institution of Water and Environmental Management pledges to achieve net…

Tectonics

Earthquakes from time immemorial have attracted the attention of the…

Tectonics

A planned kayaking expedition in Nepal took on a whole…

Tectonics

Scientists from Bristol University are working in conjunction with EDF…