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>>>滬江汶川地震專題?

An earthquake is a sudden tremor or movement of the earth's crust, which originates at or below the surface.

地震是地殼一次突然的震動(dòng)或運(yùn)動(dòng)，起源于地球表面或以下。

There are two main causes of earthquakes. They can be linked to explosive volcanic eruptions or can be triggered by tectonic activity, with the latter being the cause of most earthquakes.

地震由兩種主要原因引起。他們都跟火山爆發(fā)有關(guān)或由建筑活動(dòng)引起的。后者是大多數(shù)地震的原因。

Earthquakes in the UK are all tectonic quakes, triggered when the Earth’s crust is subjected to strain and eventually moves.

英國(guó)的地震都是由建筑物震動(dòng)，是由地殼繃緊時(shí)最終移動(dòng)引起的。

At the start of a quake there is a sudden movement within the Earth's crust and shock waves move out from that point.

震動(dòng)開始時(shí)地殼內(nèi)部有一些突然的移動(dòng)，隨后地震波開始在那一點(diǎn)傳開來。

The focus of the earthquake or tremor is often deep below the surface and difficult to map, so what is normally called the epicentre is taken as the point on the Earth directly above it.

震中心通常在表面以下深處，很難用地圖表示，所以通常我們所稱的正中心為地球最上方。

There are two scales for defining the strength of an earthquake, the Mercalli Scale and the Richter Scale.

地震強(qiáng)度用兩個(gè)級(jí)別來定義，Mercalli級(jí)別和Richter級(jí)別。

Earthquakes emit three types of waves which have their own characteristics.

地震發(fā)出兩種波，它們有各自的特征。

Primary waves are identical in character to sound waves. The ground is forced to move forwards and backwards as it is compressed and decompressed.

主要波跟聲波的特征相同，當(dāng)?shù)孛姹患訅夯驕p壓時(shí)強(qiáng)迫向前和向后移動(dòng)。

Secondary waves travel more slowly and arrive after the P-waves. They move in all directions, at speeds which depend upon the density of the rocks through which they are moving. They cannot move through liquids. They can move walls and fences, leaving them 'S' shaped.

次要波傳播的更慢，發(fā)生在P波之后。它們根據(jù)所穿過巖石的密度以不同的速度向各個(gè)方向移動(dòng)。他們不能穿過液體。但可以穿過墻和籬笆，留下S形狀的痕跡。

Surface waves are formed close to the epicentre and can only travel through the outer part of the Earth’s crust. They are responsible for the majority of the buildings damaged by earthquakes. The ground is made to move in a circular motion, causing it to rise and fall as visible waves move across the ground.

表面波在正中心形成，它只能穿過地殼外部，是大多數(shù)建筑物在地震中損壞的原因。地面環(huán)形運(yùn)動(dòng)，引起上升或下降，成為可視波橫穿地面。

>>>滬江汶川地震專題