Intra-plate Jal Az-Zor strike-slip faulting deciphering the enigma of local earthquakes in Kuwait

Abstract

Abstract Kuwait National Seismic Network (KNSN) data show the clustering of earthquakes in northern and southern clusters. Spatial correlation between these clusters and oil fields led previous studies to declare that oil production/injection triggered earthquakes, but some suggested the possibility of tectonic causes. This study addresses the genuine objective of uncovering the origin of Kuwait earthquakes by analysing relationships between earthquake spatial and temporal patterns, oil production/injection, structural and tectonic setting, and subsurface fluid pressures. A kinematic model of the Jal Az-Zor dextral-slip fault was presented as a decipherer to the earthquake's origin. The northern and southern clusters represent leading quadrants, where increased mean stress causes earthquakes. Dibdibah Trough and Kuwait Bay represent trailing quadrants with decreased mean stress and a lack of earthquakes. The small percentage of earthquakes falling outside clusters are caused by the concentration of regional compressive stresses related to Arabian Plate motion on pre-existing faults. Triggering earthquakes by oil field operations requires 10% pressure increase above the original pressures, which never occurs in Kuwait oil fields. The results of this study emphasize the significance of understanding fault kinematics to assess earthquake hazards and the need to focus on engineering requirements for developments in the leading quadrants areas.