Because P and S waves travel at different but fairly constant speeds, the interval between their arrivals increases in proportion to the distance from the earthquake focus, or initial rupture point.
由于 P 波和 S 波以不同但相当恒定的速度传播，它们到达的间隔与到震源或初始破裂点的距离成比例地增加。
2
For instance, I can instantly know the constantdistance.
例如，我可以即刻知道该恒定距离。
3
The researchers found that in the northern sky, the fine-structure constant gets smaller with increasing distance, or as astronomers look farther back in time.