Geophone for the study of elastic wave phenomena.

摘要

Geophone for detecting shear waves polarized horizontally, comprising at least one pair of electromechanical transducers, each of said appropriate transducers for detecting said waves of horizontally polarized shear (SH waves) and compression waves (P waves), wherein each transducer comprises a first output terminal with a first polarity and a second output terminal with a second polarity, said second polarity opposite said first polarity sign; each transducer has a principal axis to which is associated a vector, so that ground movement in the same direction vector becomes a potential difference with the same sign, conventionally defined positive, between the respective terminals of the transducer and a ground movement on opposite vector direction always becomes a potential difference with the same sign, conventionally defined negative, opposite quees the positive sign, between the respective terminals of the transducer an output terminal of a transducer is electrically connected with a terminal another transducer output to achieve: a sum [P + SH] of the signals representative of the shear waves SH horizontally polarized and compression waves P; a difference [P-SH] or [SH-P] between signals representative of horizontally polarized shear waves (SH) and compression waves P; compensation [[P + SH] - [P-SH]] or [[P + SH] + [SH-P]] between said sum and difference signals; in order to acquire, at the output terminals of the transducers which are not connected electrically and conversely, a signal which is representative of the shear waves polarized horizontally with an increased sensitivity and being less affected by presence of compression waves, characterized because the two transducers are arranged such that the relevant vectors are symmetric in direction and the main axes relevant are inclined to the vertical axis of the geophone (G), forming substantially equal angles (A and A) with said vertical axis, being such angles within the range between 60 and about 87 degrees.