Passive Seismic Monitoring in the Northern Emirates: Detection of Local Seismicity for Tectonic Mapping

Abstract

Seismicity is poorly understood in the United Arab Emirates (UAE). Using a large data set of microseismic data available in the UAE and Oman from 2014 to 2016, microseismic events are located and moment tensor inversion has been performed. Using a commercially available software Insite Geo (v. 3.17), a collapsing grid search algorithm combined with Tian raytracing approach has been used to map 185 events in the northern UAE between latitudes 24° to 27° and longitudes 54.2° and 58.1° at depths between 0 km to 30 km. First motion polarities and amplitudes of P and S waves were used to perform moment tensor inversion on selected 25 events with clear identifiable first arrival picks. The focal mechanisms revealed oblique thrusts due to compressional stresses from the Arabian plate moving North. The compressive forces due to the plate motion reactivated near surface reverse faults and deep-seated thrust faults which formed from the obduction of the Semail ophiolite. This resulted in source mechanisms of the observed microseismic events to show thrust faulting showing strikes in NW-SE and NE-SW directions. A series of strike-slip faults due to extensional tectonics were also mapped. These faults were produced by plate motions caused by the Zagros collision and the dextral strike-slip Zendan-Minab fault causing the Arabain Plate to move north and also creating a slight anticlockwise rotation. Combination of these events provide the necessary compressive forces on northern UAE and Oman to create the observed oblique thrust fault mechanisms. Also, these differential plate motions explain the observed strike directions of the oblique thrust fault mechanisms.

Date of Award	Apr 2023
Original language	American English
Supervisor	Mohammed Ali (Supervisor)