January 25, 2020

expert reaction to Turkey earthquake

A 6.7 magnitude earthquake was recorded in Eastern Turkey.

Prof David Rothery, Professor of Planetary Geosciences, The Open University, said:

“This earthquake at occurred on the South Anatolian fault.  This, one of the globe’s major tectonic features, is where the Turkish (or Anatolian) microplate slides westwards to make way for the Arabian microplate, which is forcing its way northwards.  This is a smaller version of the collision further east where the Indian microcontinent is colliding into Asia to throw up the Himalayas.

“This particular earthquake began at a depth of about only 10 km.  This is so shallow that there was not much rock in the way to absorb the strength of the seismic waves (shaking) radiating from the source before they reached the surface, hence the ground shaking was stronger than it would have been for a deeper earthquake of the same magnitude.

“Similar earthquakes are not uncommon in this region.  There have been seven others of magnitude 6 or more in the past 50 years.  For example a magnitude 6.4 quake 140 km northeast of this one in May 2003 killed 177 people and destroyed hundreds of buildings.

“Sadly there have been fatalities.  I would expect some poorly-constructed buildings near the epicentre to have been destroyed.  It is a rugged area, so landslides triggered by the quake could have caused destruction or death too.  Earthquake-resilient buildings, costing maybe 20% more to build than others, would generally not have collapsed in this event.

“Fortunately schools, which have larger rooms than houses, and so are more vulnerable to roof collapse, would have been unoccupied when this quake happened, fairly late on a Friday evening.  It will be interesting to see how well local schools and hospitals have stood up to this earthquake.  How to construct these so they do not kill people inside is well known, but building codes are often flouted to save money.

“Aftershocks are normal in the hours and days following an event of this size, and pose dangers to anyone trapped inside a damaged building, and to their rescuers.  There have been about a dozen aftershocks of magnitude 4 on the Richter scale.  Most others will be smaller than this, but larger aftershocks remain a significant risk for several days.”

Declared interests

None received.