A method, apparatus and system for detecting seismic waves. A sensing apparatus
is deployed within a bore hole and may include a source magnet for inducing a magnetic
field within a casing of the borehole. An electrical coil is disposed within the
magnetic field to sense a change in the magnetic field due to a displacement of
the casing. The electrical coil is configured to remain substantially stationary
relative to the well bore and its casing along a specified axis such that displacement
of the casing induces a change within the magnetic field which may then be sensed
by the electrical coil. Additional electrical coils may be similarly utilized to
detect changes in the same or other associated magnetic fields along other specified
axes. The additional sensor coils may be oriented substantially orthogonally relative
to one another so as to detect seismic waves along multiple orthogonal axes in
three dimensional space.