Patent ID: 6366537
Filing Date: 2002-04-02
Classification: G01V,Y10S

Abstract:
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.