In continuation of a fracture zone survey of BGR in 1985, there was a multichannel seismic survey of the Hayes Fracture Zone between 20°W and 27°W in the time from October 26th to November 11th, 1988. In spite of bad weather conditions, it was possible to collect a total of 1.760 km seismic and gravity data on 11 lines. From a first interpretation of the seismic monitor records on board it appears that the frequency of intra-crustal reflections in the records from the area west of 20°W is much less than on the records of the survey of the previous cruise in 1985. During a second leg in the time period from 14th November to 21th November 1988 an additional seismic survey of the Kane Fracture Zone took place with 7 supplementary profiles.
The METEOR cruise M20/3 from 4th February to 13th March 1992 had two scientific objectives: One research topic was to study the variability of the Mesozoic oceanic crust along two flow-line profiles located north of the Kane and Hayes Fracture Zones. The other research topic was the investigation of the weak magnetic anomalies in the Jurassic magnetic quiet zone north of the Canary Islands. Seismic data with a coverage of 2,400 % were acquired together with magnetic, gravimetric and hydroacoustic data along the two flow-line profiles with a total length of 1,595 km. Magnetic, gravimetric and hydroacoustic measurements were carried out on 31 profiles with a total length of 6,069 km in the Jurassic quiet zone north of the Canary Islands. On 10 of these lines multichannel seismic reflection data (2,138 km) have been acquired.
A geophysical reconnaissance survey across oceanic fracture zones has been carried out by the BGR in the eastern North Atlantic using S.V. PROSPEKTA. The geophysical measurements, including multichannel seismic reflection profiling, magnetics and gravity were concentrated on three oceanic crustal areas of Mesozoic crust which are crossed by the Hayes Fracture Zone, the Atlantis Fracture Zone and the Kane Fracture Zone respectively. 24 geophysical lines with a total length of 5,362 km have been measured during the time period from 25th October to 4th December 1985. Besides intracrustal seismic events a deep coherent seismic event is often recognizable in the monitor records between 10 - 12 s (TWT) along several lines, which probably is a reflection from the crust-mantle boundary.