After 5.12 earthquake struck sichuan province since 20xx, we, I was so frightened by an earthquake, I felt the earthquake many houses will be apart, can let many people lost their lives, is one of the world's most terrible disaster. Today I saw "China children's encyclopedia, really know anything about earthquake.
It turns out that the earthquake happened all of a sudden the vibration phenomenon, like the wind, rain, is a kind of common natural phenomena. Vibrations in the earth, in fact, very frequently, probably every 30 seconds there will be time, but most of them are very ease, people did not feel. We can feel the earthquake is due to the relative movement between earth's tectonic plates, rock is squeezed, produce a huge amount of energy to make rock failure in an instant, or make originally the already existing fracture activity, suddenly release a large amount of energy, and some of the energy to the earth's surface, make the earth trembling violently, causing strong earthquake. Started happening earthquake site is called the source, the source above the ground is called the epicenter, the ground of the devastating earthquake is the most strong place is called the magistoseismic area, while the magistoseismic area often is the place where the epicenter. When the earthquake occurred, the source of shock wave in the earth's crust to all directions called seismic waves. Seismic waves hit the ground, the result will be a disaster.
We Chinese people are very smart, as early as the eastern han dynasty, there is a man named zhang heng scientists invented to measure the earthquake Hou Feng seismograph, and our modern scientists are generally measured the spread of seismic wave speed with the help of a seismograph, the place and time of the earthquake.
Know the earthquake knowledge, learning even before the earthquake early warning and self protection method, I think, to know that knowledge is very useful for our own.
自從20xx年我們四川發生5.12大地震之後，我就特別害怕地震，我覺得地震會震垮很多房屋，會讓許多人失去生命，是世界上最可怕的災難。今天我看了《中國少年兒童百科全書》後，才真正知道地震是怎么回事。
原來，地震是突然間發生的大地震動現象，就像颳風、下雨一樣，是一種很普遍的自然現象。地球上的震動實際上非常頻繁，大概每30秒種就會有一次，但大多數都非常緩和，人們都沒有感覺。我們能感覺到的地震是由於地球板塊之間產生相對運動，岩石層受到嚴重擠壓，產生巨大的能量使岩石在瞬間發生斷裂，或者使原來已經存在的斷裂突然活動，釋放出大量能量，而其中一部分能量傳到地球表面，使大地劇烈地顫動，從而引起強烈地震。地震開始發生的地點稱為震源，震源上方的地面稱為震中，破壞性地震的地面最烈處稱為極震區，而極震區往往就是震中所在的地方。地震發生時，震源發出的在地殼中傳向四面八方的衝擊波稱為地震波。地震波衝擊到地面，就會引發災難。
我們中國人非常聰明，早在東漢時期，就有一位叫張衡的科學家發明了用來觀測地震的侯風地動儀，而我們現代的科學家也一般都藉助地震儀來測量地震波的傳播速度，判斷地震發生的地點和時間。
知道了地震知識以後，還要學習地震發生前的提前預警和自我保護方法，我想，了解到這些知識對我們自己是非常有用的。