Science. 1973 May 11;180(4086):632-5. doi: 10.1126/science.180.4086.632.
A large precursory change in seismic body-wave velocities occurred before the earthquake in San Fernando, California. The discovery that this change is mainly in the P-wave velocity clearly relates the effect to the phenomenon of dilatancy in fluid-filled rocks. This interpretation is supported by the time-volume relation obtained by combining the present data with the data from previous studies. The duration of the precursor period is proportional to the square of an effective fault dimension, which indicates that a diffusive or fluid-flow phenomenon controls the time interval between the initiation of dilatancy and the return to a fully saturated condition which is required for rupture.
在加利福尼亚州圣费尔南多发生地震之前，地震体波速度发生了大幅前兆变化。发现这种变化主要发生在 P 波速度中，这显然将这种效应与充液岩石中的扩容现象联系起来。这种解释得到了通过将当前数据与以前研究的数据相结合而获得的时-体关系的支持。前导期的持续时间与有效断层尺寸的平方成正比，这表明扩散或流体流动现象控制着扩容开始和完全饱和状态之间的时间间隔，而这种状态是破裂所必需的。
