Roman mausoleum tested for ancient earthquake damage

Built under a sheer cliff, with a commanding view of the forum and castle in the ancient city of Pinara in Turkey, a Roman mausoleum has been knocked off-kilter, its massive building blocks shifted and part of its pediment collapsed. The likely cause is an earthquake, according to a new detailed model by Klaus-G. Hinzen and colleagues at the University of Cologne. They conclude that a 6.3 magnitude earthquake could have caused the damage, and their new finding gives seismologists a new data point to consider when they calculate the likely earthquake hazards for this southwestern region of Turkey.

Researchers have seen other signs of strong seismic activity in Pinara, most notably a raised edge to the ancient town's Roman theater that appears to be due to activity along a fault. But archaeologists and seismologists were not certain how the mausoleum sustained its damage. An earthquake seemed likely, but the mausoleum is also built under a cliff honeycombed with numerous other tombs, and damage from a rockfall seemed possible.

Hinzen and colleagues mapped the position of each part of the mausoleum using laser scans, and transferred 90 million data points collected from the scans into a 3-D computer model of the tomb. They then ran several damage simulations on the 3-D model, concluding that rockfall was not a likely cause of damage, but that an earthquake with magnitude 6.3 would be sufficient to produce the observed damage pattern to the mausoleum's heavy stone blocks.