Borehole Seismic Investigations of Fractures in Crustal Stress Regimes

利用S波地震仪可以方便、准确地观测到地壳中的定向垂直裂缝。垂直传播的S波的移动速度略有不同，这取决于S波相对于裂隙群排列的偏振程度。沿裂缝面偏振的S波的传播速度比沿裂缝面垂直排列的S波的传播速度要快。S波速差或S波分裂类似于晶体中的双折射。

Aligned vertical fractures in the crust may be conveniently and accurately observed by S-wave seismometry. Vertically propagating S-waves move at slightly different speeds depending upon the polarization of the S-waves with respect to the alignment of the fracture population. S-waves polarized along the fracture faces propagate faster than do S-waves polarized normal to aligned fracture faces. The S-wave speed differential or S-wave splitting is analogous to birefringence in crystals.