【英语时差8,16】震波决定地震的方向和速度（上）

 The ground may feel solid, but far beneath our feet, extremely hot rock at extremely high pressure is flowing like slow, underground rivers. No one has ever seen that far into the earth, but we see the results of that movement in every earthquake and volcano. When an earthquake occurs, it sends what are called “seismic¹ waves” in all directions. Because seismic waves travel faster through some kinds of rock than through others, geologists² can guess what sort of rock the waves are traveling through based on how fast the waves travel through that part of the earth. But the speed of the seismic waves can also tell in us which direction, if any, the rock is moving. When soft, hot rock flows under high pressure, the crystals in the rock all line up like tiny toothpicks in the direction the rock is flowing.

1 seismic   

a.地震的，地震强度的

参考例句：

• Earthquakes produce two types of seismic waves.地震产生两种地震波。
• The latest seismic activity was also felt in northern Kenya.肯尼亚北部也感觉到了最近的地震活动。

2 geologists   

地质学家，地质学者( geologist的名词复数 )

参考例句：

• Geologists uncovered the hidden riches. 地质学家发现了地下的宝藏。
• Geologists study the structure of the rocks. 地质学家研究岩石结构。