专业英语翻译

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Earthquakes

Earthquakes is trembling or shaking movement of the Earth’s surface.Most earthquakes are minor https://www.360docs.net/doc/2f2999680.html,rger earthquakes usually begin with slight tremors but rapidly take the form of one or more violent shocks,and end in vibrations of gradually diminishing force called aftershocks.The subterranean point of origin of an earthquake is called its focus;the point on the surface directly above the focus is the epicenter .The magnitude and intensity of an earthquake is determined by the use of scales,e.g.,the Richter scale and Mercalli scale.

Most earthquakes are causally related to compressional stress or tensional stress built up at the margins of the huge moving lithospheric plates that make up the Earth’s surface.The immediate cause of most shallow earthquakes is the sudden release of stress along a fault,or fracture in the Earth’s crust resulting in moving of the opposing blocks of rock past one another.These movements cause vibrations to pass through and around the Earth in wave form,just as ripples are generated when a pebble is dropped into water.V olcanic eruption,rockfalls,landslides,and explosions can also cause a quake,but most of these are of only local extent.

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Evidence from radiometric dating indicates that the Earth is about 4,570 million years old.Geologists have divided Earth’s history into a series of time intervals.These time intervals are not equal in length like the hours in a day.Instead the time intervals are variable in length.Different spans of time on the time scale are usually delimited by major geological or paleontological events,such as varying rock type or fossils within the strata and mass extinctions.For example,the boundary between the Cretaceous period and the Paleogene period is defined by the first appearance of animals with hard parts.

The geologic time scale was formulated during 地震

地震颤动或发抖运动的地球表面。大部分地震是轻微地震。大地震通常开始轻微的颤动而迅速采取一个或更猛烈冲击的形式，并最终在逐渐减少振动的力称为余震。地震起源的地下点称为重心；表面上以上的重点是中心点。地震的震级和强度的尺度，确定使用例如，李希特尺度和麦加利震级。

大部分地震是因果关系的压应力或拉应力建立在巨大岩石圈板块的运动，使地球表面的空间。最浅的地震的直接原因是沿断层应力的突然释放，或断裂在地壳导致岩石过去彼此对立块体运动。这些运动引起的振动通过环绕地球以波的形式，就像涟漪时产生一个石子投进水中。火山喷发，崩塌，滑坡，和爆炸也可以引起地震，但这些只是局部性的范围。

证据来自辐射测年表明，地球的年龄大约是4570000000岁。地质学家划分地球历史划分成一系列的时间。这些时间间隔的长度像一天中的时间是不相等的。相反，时间间隔的长度是可变的。时间在时间尺度不同跨度通常是由主要的地质或古生物事件分隔的，如不同的地层和大规模物种灭绝的岩石或化石类型。例如，白垩纪和古近纪是用坚硬的部分动物的第一次出现定义之间的边界。

the early 1800s on the basis of information gained by relative age dating of sedimentary rocks and fossils in Europe.The largest divisions of geologic time are called eons.Eons are subdivided into eras,eras into periods, periods into epochs, and epochs into ages.The geologic time scale is presented in the Table below.

Eons are hundreds of millions of years in duration.In the time scale below you can see the Phanerozoic Eon is the most recent eon and began more than 540 million years ago.Eons are divided into smaller time intervals known as eras.In the time scale below you can see that the Phanerozoic is divided into three eras: Cenozoic, Mesozoic and Paleozoic.Very significant events in Earth’s history are used to determine the boundaries of the eras.

Eras are subdivided into periods.The events that bound the periods are wide-spread in their extent but are not as significant as those which bound the eras.In the time scale below you can see that the Paleozoic is subdivided into the Permian, Carboniferous, Devonian, Silurian, Ordovician and Cambrian periods.Each unit of the Phanerozoic intervals (542Ma to present) and the base of the Ediacaran is defined by a Global Standard Section and Point (GSSP), whereas the Precambrian interval is formally subdivided by absolute age, radioactive age.

The first life in the Earth,which was probably algae floating in the ocean,appeared approximately 3 billion years ago.The fossil record throughout the later portion of the Precambrian is sparse and indicates that just simple life forms of plants and animals existed in the ocean.Because of the sparsity of life,there is very little organic matter preserved in Precambrian sediments and,therefore,little in the way of petroleum source rocks.Many of the Precambrian sediments have been buried deep and are metamortphosed.They offer little in the way of reservoir rocks.Therefore,no significant deposits of gas and oil are known in Precambrian rocks. The fossil record shows that at the Paleozoic Era,a great abundance of diverse plants and animals were living in the ocean.During the Ordovician,the next period in the Paleozoic,fish evolved.Plants and animals evolved to life on the land in the next period,the Silurian.

地质时间尺度的制定在18世纪早期的基础上获得的信息相对年龄的沉积岩和化石在欧洲。地质时间最大的部门称为亿万年。亿万年分纪元，纪元为时期，时期为时代，时代到年龄。地质时间尺度下提出的表。

年是年的时间数以亿计。在时间刻度的下面你可以看到显生宙是最近EON和540000000多年前开始的。年分为更小的时间间隔称为时代。在时间刻度的下面你可以看到，显生宙分为三个时期：新生代，中生代和古生代。地球历史上非常重要的事件来确定时代的界限。

时代被细分成阶段。事件绑定的时期在他们的范围广但不为那些束缚的时代意义。在时间刻度的下面你可以看到古生代细分为石炭系，二叠系，志留系，泥盆系，奥陶系、寒武系时期。每个单位的显生宙的间隔（542ma至今）和异的基础是由一个全球标准剖面和点（GSSP），而寒武纪区间正式分为绝对年龄，放射性年龄。

在地球的第一生命，这可能是藻类漂浮在海洋中，出现了3000000000年前约。化石记录在前寒武纪的后部分稀疏，表明海洋中只是简单的生命形式存在的植物和动物。因为生命的稀疏性，很少有有机质保存在前寒武纪的沉积物，因此，在油源岩小。许多前寒武纪沉积已深埋，metamortphosed。他们很少在储层岩石的方式。因此，天然气和石油没有明显的沉积岩石称为前寒武纪。

化石记录表明，在古生代，一伟大的丰富多样的植物和动物生活在海洋中。在奥陶纪，在古生代，鱼类进化的下一阶段。植物和动物进化到生命的土地上在今后一个时期，志留系。

The Mesozoic Era,starting about 250 million years ago, is known as the age of dinosaurs and reptiles.During the Jurassic,the middle period of the Mesozoic,mammals and birds evolved but were apparently dominated by the reptiles throughout the Mesozoic.

Finer subdivisions of time are possible and the periods of the Cenozoic are frequently subdivided into epochs.Subdivision of periods into epochs can be done only for the most recent portion of the geologic time scale.This is because older rocks have been buried deeply,intensely deformed and severely modified by long-term Earth processes.As a result,the history contained within these rocks can not be clearly interpreted.

The Cenozoic is divided into two periods,the Paleogene and Neogene,and they are in turn divided into epochs. The Paleogene consists of the Paleocene, Eocene, and Oligocene epochs, and the Neogene consists of the Miocene,Pliocene,Pleistocene,and Holocene epochs, the last of which is ongoing. Historically, the Cenozoic had been divided into periods named the Paleogene (Paleocene, Eocene, Oligocene), Neogene(Miocene, Pliocene) and Quaternary (Pleistocene, Holocene).

250000000年前的中生代，被称为恐龙和爬行动物的时代，在侏罗纪时期，中生代，哺乳动物和鸟类的中间阶段，但显然占主导地位的爬行动物整个中生代。

更好的细分的时间可能与新生代时期经常被细分为历元。时期为时代细分可以只在地质时间尺度上的最近的部分做的。这是因为年长的岩石被深埋，强烈变形和长期的地球过程严重的修改。因此，包含在这些岩石的历史不能清楚的解释。

新生代分为两个时期，古近系和新近系，他们依次分为时代。古近纪包括古新世，始新世和渐新世，新近纪，并由中新世，上新世，更新世，和全新世时代，其中最后一个是持续的。从历史上看，新生代已分时段命名为古近纪（古新世，始新世，渐新世，新近纪（中新世），上新世）和第四纪（更新世，全新世）。