The Quaternary undersea valley Fosse Dangaered, and Castle Hill landslip at the English portal, caused concerns. Identified by the 1964â65 geophysical survey, the Fosse Dangaered is an infilled valley system extending 80 metres (262 ft) below the seabed, 500 metres (1,640 ft) south of the tunnel route in mid-channel.
Best Answer: Magnetic forces can be caused by an electric current. Or they can be caused by magnetic domains aligned correctly. These domains are magnetic moments created by moving atoms in the material who have an electric dipole (usually).
1 This force depends on the magnetic field, the charge and the speed. 2  The direction of this force is perpendicular to both the magnetic field and the velocity vector of the electric charge. 3  If you have an electric field in some region, that will cause a change in electric potential between two points.f you donât know the direction of the magnetic field you are trying to measure, this method wonât work. Also, if the magnetic field is very small or very large in comparison to the Earthâs horizontal component you wonât get a very accurate result.