초록 ▼

A method for the study of elastic wave phenomena in the ground, where the detection of said phenomena is carried out with the use of at least a geophone comprising at least a couple of transducers (20, 21; 37, 38), each transducer (20, 21; 37, 38) being apt to detect horizontally polarized shear wav

A method for the study of elastic wave phenomena in the ground, where the detection of said phenomena is carried out with the use of at least a geophone comprising at least a couple of transducers (20, 21; 37, 38), each transducer (20, 21; 37, 38) being apt to detect horizontally polarized shear waves, represented by SH signals, and compression waves, represented by P signals. The method comprises: i) a first detection, by means of one of said transducers (20, 21; 37, 38) of the sum of said P and PH signals (P+SH); ii) a second detection, by means of the other one of said transducer (20, 21; 37, 38) of the difference between said P and SH signals ([P-SH] or [-P+SH]); iii) the compensation ([P+SH]-[P-SH]) or [P+SH]+[P-SH]) between said first and said second detection, in order to acquire signals being representative of horizontally polarized shear waves with an increased sensitivity and being less affected by the presence of compression waves.

대표청구항 ▼

1. A geophone for detecting horizontally polarized shear waves, comprising at least first and second electromechanical transducers for detecting horizontally polarized shear waves and compression waves, whereineach of said transducers has a principal axis with a corresponding vector, and comprises a

1. A geophone for detecting horizontally polarized shear waves, comprising at least first and second electromechanical transducers for detecting horizontally polarized shear waves and compression waves, whereineach of said transducers has a principal axis with a corresponding vector, and comprises a first output terminal with a first polarity, a second output terminal with a second polarity, the second polarity being of opposite sign to the first polarity, and sensor means responsive to movement in the ground for producing between said first output terminal and second output terminal a potential differential of one polarity when said movement is in a direction along the vector and a potential differential of polarity opposite to said one polarity when said movement is in a direction opposite to that of the vector; said transducers being in mutually spaced relationship, one of the first and second output terminals of said first transducer being directly connected to one of the first and second output terminals of said second transducer for producing between the other of said first and second terminals of said first transducer and the other of said first and second terminals of said second transducer, a signal which is more sensitive to horizontally polarized shear waves than it is to compression waves, said first and second transducers being rigidly mounted on a common support with their respective principal axes symmetric with respect to a vertical axis, the magnitude of the angle between each of said principal axes and said vertical axis being in the range of 60 to 120 degrees.