Method of measuring the anisotropy of propagation or reflection of a transverse wave, particularly a method of geophysical prospecting by measurement of the anisotropy of propagation or of reflection of shear waves in rocks

A method of measurement of anisotropy of propagation of a transverse wave between two given reference points of a non-isotropic medium to be studied,

• particularly a method of geophysical prospecting by measurement of anisotropy of propagation of shear waves in rocks,
• wherein:
• two sources and a detector are arranged along a single ray vector, said sources being placed at the location of said respective points of reference,
• said sources are excited by respective excitation signals producing transverse waves in said medium,
• respective resultant measurement signals produced by said detector are received,
• from said excitation signals and said measurement signals, a transfer function of said medium along each of said two respective source-detector paths is determined,
• a differential transfer function referred to as the anisotropic shear wave transfer function of said medium for propagation between said two points of reference is deduced.

A method of measuring anisotropy of the propagation of a transverse wave between two given reference points, located on the same propagation path and referred to as mirror points, appropriate for creating substantially isotropic reflections from a transverse wave of a non-isotropic medium to be studied,

• particularly a method of geophysical prospecting by measurement of anisotropy of propagation of shear waves in rocks,
• wherein:
• a source and a detector are arranged on the same path as said two mirror points,
• said source is activated by an excitation signal producing a transverse wave in said medium, in a manner such that said wave propagates along a single ray vector in a first direction as far as said two mirror points, said wave being then reflected at each of said points of reference and propagating back along said ray vector in the opposite direction as far as said detector,
• respective result and measurement signals produced by said detector are received,
• a transfer function referred to as the anisotropic shear wave transfer function of said medium along each of said two respective source-point of reference-detector paths is determined
• a differential transfer function of said medium between said two points of reference is deduced.

A method of measurement of anisotropy of reflection of a transverse wave at a given point of reference referred to as mirror point, appropriate for creating a non-isotropic reflection of said transverse wave, in a substantially isotropic medium,

• particularly a method of geophysical prospecting by measurement of anisotropy of reflection of shear waves in rocks,
• wherein:
• a source and a detector are arranged on the same propagation path as said mirror point,
• said source is excited by an excitation signal producing a transverse wave in said medium, in a manner such that said wave propagates along a ray vector in a first direction as far as said point of reference, where it is reflected and it propagates back along said ray vector in the reverse direction as far as said detector,
• respective result and measurement signals produced by said detector are received by said detector,
• a transfer function referred to as the anisotropic shear wave transfer function for said reflector at said mirror point is determined.