WP-1

Present-day kinematics and Seismic Hazards

The main objective of WP-1 is to better quantify and understand the present day kinematics and seismic hazards in NW Africa through multidisciplinary studies combining geodesy, morphotectonic and seismicity.

Beneficiary & Participant Organisations 

CSIC, UM2, EVORA, UAE, UM5, CRAAG

WP-1

Head of working group

Present-day kinematics and seismic hazards

Abdel Hakim Ayadi (CRAAG) & Jesus Galindo (UGR-CSIC)

Task 1.1: Geodesy

Philippe Vernant (UM2) & Mourabit Taoufik (UAE) 

Task 1.2: Morphotectonic

Jean Franςois Ritz (UM) & Maouche Said (CRAAG)

Task 1.3: Seismicity and Seismic Hazard

Abdelilah Tahayt (UM5)Harbi Assia (GRAAG)Bento Caldeira (Evora)

 

Description of work

Task 1.1 : Geodesy: In October 2011 MEDYNA researchers installed and surveyed 16 new SGPS sites in the study area (focus on N. Morocco). We resurvey these and older GPS sites. The 3-4 years duration of the observation will be sufficient to determine reliable site velocities with uncertainties of ~1 mm/yr (global) and ~0.4 mm/yr (regional), and to start estimating vertical motions. All the results will be integrated with those of other international colleagues working in the area.

Task 1.2: Morphotectonic: Field studies will focus on the deformation zones as defined by the GPS velocity field. We shall use kinematic GPS and/or total stations together, as well as dating methods (in-situ 3He & 10Be, OSL, 14C), to estimate and date displacements of offset markers. In particular, we plan to carry out a detailed morphotectonic study along faults preserving outstanding left-lateral/normal displacement within an alluvial terrace. There, DEM of the area and detailed geological mapping, combined with in-situ 3He & 10Be dating of the offset terrace should allow us to determine precisely the kinematics of the fault (strike, dip, rake and slip rate) and the recurrence intervals of earthquakes.

Task 1.3: Seismicity and Seismic Hazards: We will precisely analyze the instrumental seismicity recorded through already established collaborations. This new analysis will take advantage of the results issued from the TopoIberia and PICASSO campaigns, especially in giving a more precise seismic wave velocity model at lithospheric scale. In that way, we will reduce the location inaccuracies of the crustal seismicity and will constrain better the rupture mechanisms.  In a second stage, we will set up temporary seismological surveys east and west of the Rif-Tell belt. This will allow the study of the seismicity in relationship to the observations of Tasks 1.1 and 1.2 and the characterization of the tectonic structures governing the bloc kinematics and dynamics in the area.