This allowed Preventing_or_letting the power vacuum which the civil war Military_operation had fostered Creating in the Caliphate 's provinces to grow Expansion , and several local rulers sprang up in Jazira , Syria and Egypt .

However , the figure of 230,000 dead Death is based on a historical conflation of this earthquake Catastrophe with earthquakes Catastrophe in November 1137 on the Jazira plain and the large seismic event of 30 September 1139 in the Transcaucasian city of Ganja .