9627855 Barazangi This research is a collaboration between Cornell University and Moroccan and Spanish research institutions to map crustal and upper mantle seismic structure in the convergent continental plate boundary between Africa and Iberia. This complex deformation boundary is active today, as evidenced by both shallow and intermediate depth seismicity, and includes the Moroccan Rif and Spanish Betic interplate mountain belts, which constitute the Gibraltar Arc, and the Alboran Sea. A number of competing models have been suggested to explain the apparent coeval development of these striking arcuate fold and thrust mountain belts and the neighboring Alboran basin since the early Miocene. Possible models range from trapped microplates to subduction or delamination. Combined digital seismic networks in Spain and Morocco (installation of the latter was in part supported by NSF funding) provide 49 stations for data analysis. Precise earthquake location and focal mechanism determination along with 3-D seismic velocity and attenuation mapping will be used to discriminate among the competing models of deformation. ***
