Seismic catastrophes in historical times in Arabia – Destruction of the city of Qalhat (Oman) in the 16th century

Abstract

The Arabian Peninsula is surrounded by seismically highly active plate margins, while the interior seems to be free from destructive earthquakes. We report two historical earthquakes in Qalhat, Oman, >300 km from any plate boundary and provide archaeoseismological analysis of ruined buildings. The first quake hit the city in 1497 AD with an intensity VII at most; the community survived and damage was repaired. The second event caused total devastation (intensity X-XI), sometime between 1580 and 1592. The city never recovered from the latter; it has been a field of ruins ever since. ShakeMap modeling yielded magnitude Mw 5.5 for the first and Mw 6.5–7.0 for the second earthquake. We suggest that the strike-slip Tiwi Fault or the reverse Qalhat Fault caused the first, while the reverse Qalhat Fault might have caused the second earthquake.