DInSAR coseismic surface deformation of the 2023 Mw 6.8 Al Haouz earthquake(High Atlas Mountains, Morocco)

On 8th September 2023, the Al Haouz province in Morocco was struck by a strong earthquake of 6.8 Mw. The mainshock was generated by a reverse fault with an ENE-WSW orientation, as suggested by the derived focal mechanism.  

To obtain preliminary information of a seismic event, and to characterize the associated seismotectonic framework, in the last decades, the combination of field geology with satellite observations is becoming gradually more frequent. In particular, the DInSAR technique can be a powerful method of analysis to have an initial detailed information on the deformation field produced by the earthquake.  

In the present study, to understand the deformation field induced by the event and the structures involved, the DInSAR technique has been applied to obtain displacement maps in LOS, vertical, and horizontal (E-W) directions. On these maps, the geological meaning of both the vertical and horizontal displacement components is interpreted in the framework of the known tectonic structures of the Western High Atlas Belt. The inferred coseismic deformation along its vertical component shows a wide antiform characterized by an overall E-W trend and a slight southward vergence. On the other side, the horizontal (E-W) component of the deformation seems to be affected by the flexuring of the antiform flanks.  

Integrating the retrieved DInSAR maps with published geological observations and preliminary seismological data, it is possible to demonstrate how the coseismic deformation pattern may be affected not only by a possible activity of the main Tizi n’test fault but also by the far western High Atlas frontal thrust and by possible blind faults, better oriented to the vertical deformation field.