原文：地震是指巖石圈在內(nèi)力作用下脫然發(fā)生破裂,地球內(nèi)能以地震波的形式強(qiáng)烈釋放出來,從而引起一定范圍內(nèi)地面震動(dòng)的現(xiàn)象.
發(fā)生地震的原因很多,根據(jù)地震的成因,可以把地震分為以下幾種：
1．構(gòu)造地震
由于地下深處巖層錯(cuò)動(dòng)、破裂所造成的地震稱為構(gòu)造地震.這類地震發(fā)生的次數(shù)最多,破壞力也最大,約占全世界地震的90%以上.
2．火山地震
由于火山作用,如巖漿活動(dòng)等引起的地震稱為火山地震.只有在火山活動(dòng)區(qū)才可能發(fā)生火山地震,這類地震只占全世界地震的7%左右.
3．塌陷地震
由于地下巖洞或礦井頂部塌陷而引起的地震稱為塌陷地震.這類地震的規(guī)模比較小,次數(shù)也很少,即使有,也往往發(fā)生在溶洞密布的石灰?guī)r地區(qū)或大規(guī)模地下開采的礦區(qū).
4．誘發(fā)地震
由于水庫蓄水、油田注水等活動(dòng)而引發(fā)的地震稱為誘發(fā)地震.這類地震僅僅在某些特定的水庫庫區(qū)或油田地區(qū)發(fā)生.
5．人工地震
地下核爆炸、炸藥爆破等人為引起的地面振動(dòng)稱為人工地震. 人工地震是由人為活動(dòng)引起的地震.如工業(yè)爆破、地下核爆炸造成的振動(dòng)；在深井中進(jìn)行高壓注水以及大水庫蓄水后增加了地殼的壓力,有時(shí)也會(huì)誘發(fā)地震.
地震發(fā)生時(shí),最基本的現(xiàn)象是地面的連續(xù)振動(dòng),主要是明顯的晃動(dòng).在震區(qū)的人在感到大的晃動(dòng)之前,有時(shí)首先感到上下跳動(dòng).這是因?yàn)榈卣鸩◤牡叵孪虻孛鎮(zhèn)鱽?縱波首先到達(dá)的緣故.橫波接著產(chǎn)生大振幅的水平方向的晃動(dòng),是造成地震災(zāi)害的主要原因.
地震對(duì)自然界景觀產(chǎn)生很大影響,最主要的后果是地面出現(xiàn)斷層和地裂縫.大地震的地表斷層常綿延幾十至幾百千米,往往具有較明顯的垂直錯(cuò)距和水平錯(cuò)距,能反映出震源處的構(gòu)造變動(dòng)特征.但并不是所有的地表斷裂都直接與震源的運(yùn)動(dòng)相聯(lián)系,它們也可能是由于地震波造成的次生影響.特別是地表沉積層較厚的地區(qū),坡地邊緣、河岸和道路兩旁常出現(xiàn)地裂縫,這往往是由于地形因素,在一側(cè)沒有依托的條件下晃動(dòng)使表土松垮和崩裂.地震的晃動(dòng)使表土下沉,淺層的地下水受擠壓會(huì)沿地裂縫上升至地表,形成噴沙冒水現(xiàn)象.大地震能使局部地形改觀,或隆起,或沉降.使城鄉(xiāng)道路坼裂、鐵軌扭曲、橋梁折斷.在現(xiàn)代化城市中,由于地下管道破裂和電纜被切斷造成停水、停電和通訊受阻.煤氣、有毒氣體和放射性物質(zhì)泄漏可導(dǎo)致火災(zāi)和毒物、放射性污染等次生災(zāi)害.在山區(qū),地震還能引起山崩和滑坡,常造成掩埋村鎮(zhèn)的慘劇.崩塌的山石堵塞江河,在上游形成地震湖.
英語翻譯：
Earthquake refers to the lithosphere in internal force descend from natural fracture, the earth in the form of seismic waves can strongly released, resulting in a certain range ground vibration phenomenon.
The earthquake many reasons, according to the genesis of earthquakes, can put divided into the following several earthquake:
1. Structural earthquake
Due to the deep underground strata rupture, by the collapse of the earthquake as structural earthquake. This kind of earthquake the most times, damaging the largest, accounts for about more than 90 percent of the world earthquake.
Volcanic earthquake 2.
Due to volcanic action, like the magma activity caused earthquake known as the volcano earthquake. Only in volcanic area can occur volcanic earthquake, this kind of earthquake accounts for only 7% of the world earthquake.
Earthquake collapse 3.
Due to the underground caves or mines top subsidence caused by the earthquake known as the collapse of earthquake. This kind of earthquake relatively small size, number are also few, although have, also often occur in cave cloudy limestone region or large-scale underground mining of mining area.
Induce earthquake 4.
Because of the initial impoundment of the reservoir and activities such as injection water caused by earthquake known as the induced earthquake. This kind of earthquake only in certain reservoir or oilfield area happen.
Artificial earthquake 5.
Underground nuclear explosion, explosives are caused by artificial ground vibration called artificial earthquake. Artificial earthquake is caused by human activities of earthquake. Such as industrial, underground nuclear explosion caused by blasting vibration, In deep water in high pressure and large reservoir impounding increased crustal stress, sometimes also can induce earthquake.
When an earthquake occurs, the most basic phenomenon is the ground of continuous vibration, mainly is obvious shaking. In the quake area people feel great shaking before, sometimes first feel about beats. This is because seismic waves from underground to ground came that p-wave first reach's sake. S-wave then produce the large amplitude of the horizontal wobble, is the main cause of the earthquake disaster.
The earthquake on nature landscape impact, the main consequence is ground faulting and ground fissure. Earthquake ground fault often to several hundred kilometers stretching dozens, often have the obvious vertical and horizontal distance from the fault fault, can reflect source in the tectonic change characteristics. But not all surface rupture directly with focal the movements of link, they can also be caused by seismic waves cause secondary influence. Especially surface sediments thicker areas, sloping edge, rivers and both sides the path, which often appear ground fissures are often the result of terrain factors, on the side without relying on shaking that under the condition of surface baggy and split. Earthquake jolts make elongate-shaped sinking, shallow groundwater suffers extruding will rise to the surface along the ground fissures, forming sandblasting take water phenomenon. Large earthquakes can make local terrain change, or uplift, or settlement. Make urban and rural road bran, rails distortion, bridge broken. In modern city, as underground pipes burst and cable was cut off water, power and communications caused by. Gas, toxic gases and radiation can cause fire and poisons, radioactive pollution and so on secondary disasters. In the mountains, the earthquake can cause landslides and landslides, often cause bury towns tragedy. Collapse of rocks blocked rivers, formed in upstream quake lake.