爱华网Q: What is an earthquake andwhat causes them to happen?
什么是地震？什么引起地震？
A: An earthquake is caused by asudden slip on a fault. The tectonic plates are always slowlymoving, but they get stuck at their edges due to friction. When thestress on the edge overcomes the friction, there is an earthquakethat releases energy in waves that travel through the earth's crustand cause the shaking that we feel.
答：地震由断层上的突然滑动引起。构造板块总是在缓慢移动，但由于摩擦力的作用导致板块边缘粘贴锁闭。当板块边缘应力突破摩擦力时，就产生了地震，释放的能量以地震波的形式穿越地壳，形成我们感觉到的震动。
In California there are twoplates - the Pacific Plate and the North American Plate. ThePacific Plate consists of most of the Pacific Ocean floor and theCalifornia Coast line. The North American Plate comprises most theNorth American Continent and parts of the Atlantic Ocean floor. Theprimary boundary between these two plates is the San Andreas Fault.The San Andreas Fault is more than 650 miles long and extends todepths of at least 10 miles. Many other smaller faults like theHayward (Northern California) and the San Jacinto (SouthernCalifornia) branch from and join the San Andreas Fault Zone. ThePacific Plate grinds northwestward past the North American Plate ata rate of about two inches per year.
在California有2个构造板块——太平洋板块和北美板块。太平洋板块包括大部分的太平洋洋底和California海岸线。北美板块包括大部分北美大陆和大西洋洋底。二者之间的主要边界就是SanAndreas 断层。San Andreas断层长超过650英里，延伸至地下至少10英里。许多其它小一些的断层，比如Hayward（北California）和SanJacinto （南California）的断层分支起自并且汇入SanAndreas断层带。太平洋板块以每年2英寸的速度经过北美板块向西北摩擦运动。
Parts of the San Andreas Faultsystem adapt to this movement by constant "creep" resulting in manytiny shocks and a few moderate earth tremors. In other areas wherecreep is NOT constant, strain can build up for hundreds of years,producing great EQs when it finally releases.
有部分的San Andreas断裂系通过持续的蠕滑来适应板块边界的这种摩擦，形成了很多小地震和一些中等程度的地震。在其它的地区，当这种蠕滑并不持续时，应力就会在几百年范围内积累，当应力最终释放时，就会产生大地震。
看图学习：找找看上文中提到的California在哪里？找找看我们中国在哪里？中国属于哪个板块（plate）?
