The Nazret=DGra area forms a segment of the northernrnpart of the Main Ethiopian Rift. The region is character-'rnized by a complicated morphology which is a result ofrnseveral episodes of volcanism and tectonism.rnThe volcanic rock units outcropping in the area arernprincipally bimodal in nature and it is possible to sub~rndivide them into 6 groups according to their spatialrndistribution. The groups include; the stratoid EasternrnMargin and Dera-Nazrot group mainly formed by a seriesrnof flood basalts inter layered with ignimbrites andrnRhyolites; Keleta group, representing the oldest riftrnfloor product and constituted by Ash flows and Ignimbrities;rnBoku and Gedemsa group,'which are rosults of central typernvolcanic activity evidenced by preserved caldera of Gedemsarnand destructed caldera of Boku, giving rise to Pantellerites,rnRhyolites and pumice fall deposits and Melkasa group whichrnis constituted by basaltic spatter concs and associatedrn'AA' type lavn f1.ow. The nge of the rocks vary from 1.7 myrnto 0.06 my.rnThe large volume of acidic product as compared to thernbasaltic one and the lack of transitional rock units suggestrnthat there is a pnrtial melting of the lower crust probablyrninduced by intrusion of large bodies of basaltic magma From Tectonic POitit of view, tho area is chAracterizedrnby right stepping, "8n echelon" halt grabens, grabens andrnfaults which affect evan the youngest rock outcropping inrnthe region, The geometry of these structures i,D. an oversteppingrntowards the right suggest a left lateral motionrnalong this part of the rifto The theory is substantiatedrnby meso-scale structural data which has been collectedrnfrom, small faults with slicklines, extensional fracturesrnand joints which show that the area is undergoing an eastnortheast,rnwest-southwest extensiono Thus strike-sliprnsystem and oblique extension is the major mode of deformationrnfor this part of the Rift System and possibly mayrnextend across the whole length of the Main Ethiopian Rift