地震简问简答/What is an earthquake and what causes them to happen?
Q: What is an earthquake and what causes them to happen?
问：什么是地震，造成地震发生的原因是什么？
A: An earthquake is caused by a sudden slip on a fault. The tectonic plates are always slowly moving, but they get stuck at their edges due to friction. When the stress on the edge overcomes the friction, there is an earthquake that releases energy in waves that travel through the earth's crust and cause the shaking that we feel.
答：地震是由断层的突然滑动造成的。板块一直在缓慢的移动中，但它们的边缘会因为摩擦力而挤在一起。当在边缘上的压力超过摩擦力时，能量通过地震以波的形式释放出来，穿过地壳造成我们所感觉到的震动。
In California there are two plates - the Pacific Plate and the North American Plate. The Pacific Plate consists of most of the Pacific Ocean floor and the California Coast line. The North American Plate comprises most the North American Continent and parts of the Atlantic Ocean floor. The primary boundary between these two plates is the San Andreas Fault. The San Andreas Fault is more than 650 miles long and extends to depths of at least 10 miles. Many other smaller faults like the Hayward (Northern California) and the San Jacinto (Southern California) branch from and join the San Andreas Fault Zone. The Pacific Plate grinds northwestward past the North American Plate at a rate of about two inches per year.
在加利福尼亚州有两个板块——太平洋板块和北美洲板块。太平洋板块包括大部分太平洋海底和加利福尼亚海岸线。北美洲板块包括大部分北美大陆和部分大西洋海底。这两个板块的主要边界是圣安第斯断层。圣安第斯断层超过650英里（译注：约1046公里）长，至少10英里（译注：约16公里）深。许多其他小一些的断层，比如Hayward（加利福尼亚北部）和San Jacinto（加利福尼亚南部）断层从圣安第斯断层区分支出来或连接到其中。太平洋板块向西北方（译注：似乎应该是东北？）往北美洲板块移动，移动速度大约是每年两英寸（译注：25.4厘米）。
Parts of the San Andreas Fault system adapt to this movement by constant "creep" resulting in many tiny shocks and a few moderate earth tremors. In other areas where creep is NOT constant, strain can build up for hundreds of years, producing great EQs when it finally releases.
部分圣安第斯断层系统可以通过连续的“爬行（creep）”来适应这种移动，这会造成很多微小的震动和一些中等的地表震动。在其他一些区域，这种运动不连续的发生， 压力可以累积几百年，最终释放出巨大的能量，产生大地震。
Elastic Rebound Flash Animation
For further information, see the USGS General Interest Publication "Earthquakes".
更多信息，请参见美国地质勘探局（USGS）大众兴趣出版物《地震》。