The 1138-1139 and 1156-1159 destructive seismic crises in Syria, south-eastern Turkey and northern Lebanon

Abstract

The aim of this study is to shed light ontwo important destructive seismicsequences, about 20 years apart (1138–1139and 1156–1159), which hit the northernsector of the Dead Sea transform faultsystem (DSTFS), in the easternMediterranean region. Although some ofthese earthquakes were already known to thescholarly tradition, the interpretationsprovided until today have largely beenpartial and characterised by uncertaintiesand discrepancies among the variousauthors. Our study has developed throughresearch into the original Arabic, Syriac,Armenian and Latin texts and a criticalanalysis relating to a territory fragmentedby the presence of the Christian-Latinstates. This analysis has allowed us toshed light on the already existing, albeitoften uncertain, information and to add newelements of these two important series ofearthquake shocks to our knowledge base.As regards the first seismic sequence(October 1138–June 1139), apart from havingdefined the date with greater accuracy,eight new locations affected have beenidentified, unknown to previous studies.The shocks jolted a vast area withdestructive effects, including theterritory of Aleppo (modern Halab, Syria)and the western part of the region ofEdessa (modern Urfa, Turkey).The second seismic sequence (September1156–May 1159) was much longer anddevastating, and hit a huge area, includedbetween the present-day territories ofnorth-western Syria, northern Lebanon andthe region of Antioch (modern Antakya, insouthern Turkey). A detailed analysis ofthe primary sources has allowed toreconstruct the series of shocks withchronological detail of the effects,improving our previous knowledge. Lastly,the authors formulate an hypothesis as tothe possible seismogenic zones affected.