VOA慢速英语2014 科学家绘制新的海底地图

 

Scientists Create New Maps of Ocean Floor 科学家绘制新的海底地图

Until recently, scientists had mapped only about 20 percent of the sea floor. But our knowledge of the deep seas is changing because of information from satellites. Scientists have produced a new map that provides a detailed¹ picture of the oceans. The map is expected to help oceanographers, industry and governments.

The new map is two times as detailed as the map made 20 years ago. David Sandwell is a geophysics professor at the Scripps Institution of Oceanography at the University of California. He and other scientists worked on the mapping project. He says they turned to space to look deeper into the ocean. He spoke² to VOA on SKYPE.

“The way we’re doing that is to use a satellite altimeter, a radar³ to map the topography of the ocean surface. Now that seems sort of strange that you'd map the topography of the ocean surface when you really want to get at the sea floor. But, the ocean surface topography has these bumps and dips due to gravitational effects that mimic⁴ what’s on the sea floor.”

The scientists collected and studied information from two satellites. Some of the data came from the European Space Agency's Cryo-2 satellite. It was placed in Earth’s orbit to watch sea ice. The other satellite is the American space agency’s Jason-1. It is studying the surface of the oceans. Scientists combined the satellite data with images gathered by sonar equipment on ships. Sonar works by sending sound waves through the water. When the sound waves hit an object, its presence is confirmed.

“That enables us to look at smaller-scale features and also features that are buried by sediments⁵ in the ocean basins.”   

The new map shows the sea floor as it has never been seen before. It shows thousands of underwater mountains and places where continents pulled apart. It shows where earthquakes were active many years ago. They all are buried deep underneath⁶ the ocean floor.

In one place, three mountain ridges⁷ join at the same area. Huge tectonic plates can be seen clearly there.

“It’s called the Indian Ocean Triple Junction⁸. It’s one of my favorite spots in the ocean because it really displays the theoretical aspects of plate tectonics perfectly⁹. You have three plates -- the African plate, and the Indo-Australian plate and the Antarctic plate -- all connected at this one point in the center of the Indian Ocean.”

David Sandwell says the map is a powerful tool for fisheries, those interested in protecting the environment and for oil exploration.

“(The) petroleum¹⁰ exploration industry is interested in how to reconnect the continents, bring them back together tectonically so you can map the basins (on) one continental¹¹ margin¹² -- say, Africa -- and use that to establish where the similar basin would be on the other continental margin in South America.”

If scientists know that information, they may be able to find oil fields.

The new data also will help scientists improve their estimates of ocean depths. This information can help ships travel safely and improve military operations and scientific projects worldwide.  

Words in This Story

surface – n. the upper layer of an area of land or water

map – n. a picture or chart that shows the rivers, mountains and streets in a particular area

detailed – adj. including many details; including a lot of information

device – n. an object, machine, or piece of equipment that has been made for some special purpose

underneath – prep. below or beneath (something)

“This new gravity map really provides a reconnaissance tool for planning shipboard surveys. You don’t have to go out with your ship and start looking for something new -- we can target that with the gravity and then go out with the ship and do the high resolution survey to really understand these features.”

1 detailed   

adj.详细的，详尽的，极注意细节的，完全的

参考例句：

• He had made a detailed study of the terrain.他对地形作了缜密的研究。
• A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。

2 spoke   

n.（车轮的）辐条；轮辐；破坏某人的计划；阻挠某人的行动 v.讲，谈（speak的过去式）；说；演说；从某种观点来说

参考例句：

• They sourced the spoke nuts from our company.他们的轮辐螺帽是从我们公司获得的。
• The spokes of a wheel are the bars that connect the outer ring to the centre.辐条是轮子上连接外圈与中心的条棒。

3 radar   

n.雷达，无线电探测器

参考例句：

• They are following the flight of an aircraft by radar.他们正在用雷达追踪一架飞机的飞行。
• Enemy ships were detected on the radar.敌舰的影像已显现在雷达上。

4 mimic   

v.模仿，戏弄；n.模仿他人言行的人

参考例句：

• A parrot can mimic a person's voice.鹦鹉能学人的声音。
• He used to mimic speech peculiarities of another.他过去总是模仿别人讲话的特点。

5 sediments   

沉淀物( sediment的名词复数 )； 沉积物

参考例句：

• When deposited, 70-80% of the volume of muddy sediments may be water. 泥质沉积物沉积后，体积的70-80％是水。
• Oligocene erosion had truncated the sediments draped over the dome. 覆盖于穹丘上的沉积岩为渐新世侵蚀所截削。

6 underneath   

adj.在...下面，在...底下；adv.在下面

参考例句：

• Working underneath the car is always a messy job.在汽车底下工作是件脏活。
• She wore a coat with a dress underneath.她穿着一件大衣，里面套着一条连衣裙。

7 ridges   

n.脊( ridge的名词复数 )；山脊；脊状突起；大气层的)高压脊

参考例句：

• The path winds along mountain ridges. 峰回路转。
• Perhaps that was the deepest truth in Ridges's nature. 在里奇斯的思想上，这大概可以算是天经地义第一条了。

8 junction   

n.连接，接合；交叉点，接合处，枢纽站

参考例句：

• There's a bridge at the junction of the two rivers.两河的汇合处有座桥。
• You must give way when you come to this junction.你到了这个路口必须让路。

9 perfectly   

adv.完美地，无可非议地，彻底地

参考例句：

• The witnesses were each perfectly certain of what they said.证人们个个对自己所说的话十分肯定。
• Everything that we're doing is all perfectly above board.我们做的每件事情都是光明正大的。

10 petroleum   

n.原油，石油

参考例句：

• The Government of Iran advanced the price of petroleum last week.上星期伊朗政府提高了石油价格。
• The purpose of oil refinery is to refine crude petroleum.炼油厂的主要工作是提炼原油。

11 continental   

adj.大陆的，大陆性的，欧洲大陆的

参考例句：

• A continental climate is different from an insular one.大陆性气候不同于岛屿气候。
• The most ancient parts of the continental crust are 4000 million years old.大陆地壳最古老的部分有40亿年历史。

12 margin   

n.页边空白；差额；余地，余裕；边，边缘

参考例句：

• We allowed a margin of 20 minutes in catching the train.我们有20分钟的余地赶火车。
• The village is situated at the margin of a forest.村子位于森林的边缘。