Today's M7.8 earthquake in Turkey occurred in the East Anatolian Fault zone.
Although this fault is a known hazard, the quake is unusual. Today's M7.8 released >2x as much energy as the largest recorded quakes in the region (M7.4).
Image credit: Kyle Bradley
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Although this fault is a known hazard, the quake is unusual. Today's M7.8 released >2x as much energy as the largest recorded quakes in the region (M7.4).
Image credit: Kyle Bradley
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Earthquakes (most tiny) illustrate that the faults are not one, but many: a zone of complex deformation as the crust is crushed between converging plates.
This is part of the great collision zone that extends W to the Alps & E to the Himalaya.
Image credit: Kyle Bradley
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This is part of the great collision zone that extends W to the Alps & E to the Himalaya.
Image credit: Kyle Bradley
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Here, the Arabian Plate is colliding northward with the Eurasian Plate. The East & North Anatolian faults work together: they allow the Anatolian block to squeeze westward out of the collision zone, like a watermelon seed out from your fingers.
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researchgate.net
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researchgate.net
GPS shows that across the East Anatolian Fault, the blocks are moving ~15 mm/yr relative to each other. That motion stretches the crust across the fault.
A M7.8 earthquake might slip ~5 m on average. So today's quake is catching up on about 300 years of slow stretching.
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A M7.8 earthquake might slip ~5 m on average. So today's quake is catching up on about 300 years of slow stretching.
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The tectonic movement between earthquakes is slow but the the "catching up" isn't - that snapping motion is what causes the seismic energy to emanate out from the fault, causing the Earth to quake.
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Currently PAGER estimates that >10m people experienced strong shaking, and likely thousands of fatalities.
This estimate is being refined as the earthquake model is improved - the length of the fault, orientation, & amount of slip matter.
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earthquake.usgs.gov
This estimate is being refined as the earthquake model is improved - the length of the fault, orientation, & amount of slip matter.
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earthquake.usgs.gov
Authorities in Italy have warned of a potential tsunami risk. A strike-slip earthquake like this is unlikely to produce a tsunami - no vertical ground movement - but it's possible if shaking triggers submarine landslides. Better safe than sorry?
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protezionecivile.gov.it
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protezionecivile.gov.it
How will we learn more about this earthquake? The information coming in now is seismicity: aftershocks telling us about the lateral scale of the event. So far those aftershocks extend across >250 km of the fault.
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We'll have to wait for satellite imagery, showing not just damage but how the ground itself moved. But it may be days before those images are taken.
Field reports will also take time, as will more detailed studies of the seismic shaking.
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mobile.twitter.com
Field reports will also take time, as will more detailed studies of the seismic shaking.
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mobile.twitter.com
The sun is rising over Turkey and Syria and the world changed. The ground is still shaking in aftershocks. People are in crisis and will need our help in rescue, recovery, and rebuilding. Please look for ways to contribute.
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