During METEOR-Westafrica cruise 46, leg 1, geophysical measurements were carried out off Morocco between 31°30'N and 32°30'N in the time period from the 8th October to the 5th November 1977. Altogether 1,855 km of 24-fold reflection seismic data were collected on lines ME46-02 to ME46-11 and on lines ME46-14 to ME46-19. For the purpose of planning the programme, the reflection seismic data were processed (12-fold stack) aboard. 3,465 km of magnetic, gravimetric and bathymetric data were collected on lines ME46-01 to ME46-26 using the new BGR digital recording system. Along lines ME46-101 and ME46-102 with a total length of 209 km refraction seismic measurements were carried out with 6 moored telemetric buoys. A total of 164 shots with charges of 5 kg up to 200 kg were fired along the two lines in distances of about 1.5 km. A distinct fault zone was discovered in the area of investigation which is associated with a positive magnetic anomaly. The fault zone strikes NNE-SSW and probably marks the ocean-continent boundary. Beside diapiric structures (salt) allochthonous structures - thrust structures - are widespread features east of the discovered fault zone and below the lower continental slope. The seismic data indicate that the evolution of the old continental margin of the East Atlantic was also controlled by large scale gravity tectonics.