标签:
地震知识s波p波原声波面波体波次生波英文杂谈 |
分类: 地震英语 |

Q: What is a P wave? An S wave?
问:什么是P 波?S 波?
A: When an earthquake occurs, it releases energy in the form of seismic waves that radiate from the earthquake source in all directions. The different types of energy waves shake the ground in different ways and also travel through the earth at different velocities. The fastest wave, and therefore the first to arrive at a given location, is called the P wave. The P wave, or compressional wave, alternately compresses and expands material in the same direction it is traveling. The S wave is slower than the P wave and arrives next, shaking the ground up and down and back and forth perpendicular to the direction it is traveling. Surface waves follow the P and S waves.
答:当一个地震发生时,它以从震源向各个方向发生的地震波的形式释放能量。不同类型的能量波以不同的方式晃动地面并且以不同的速度穿越地球。最快的波,也就是最先达到特定地点的波,为P波。P波,或称压缩波,在其传播过程中在同一方向交替压缩和拉伸介质(见上图)。S波比P波慢,在P波后紧邻着到达,垂直于它的传播方向上下、前后晃动地面。面波在P波和S波后面到达。
注:
P、S波是体波,是原生波。面波是次生波。波在传播过程中,从固体弹性介质传播至固体弹性介质与非弹性介质的分界面,比如地表(地壳与空气的分界面,即固体与气体的分界面),会产生次声波。P波、S波传播到地表,就会形成复杂的复合地面波,称为面波,包括love波和瑞利波。瑞利波看起来与S波像,但随深度衰减;love波(拉夫波),看起来起来就像水平的S波。二者破坏力很大。
