VOA慢速英语--科学家发现了'风暴地震', 它们是啥？

Scientists Have Discovered ‘Stormquakes.’ What Are They?

Scientists say they have discovered an earthquake-like event that can happen during a hurricane or other powerful ocean storms. They are calling it a “stormquake.”

Researchers came up with this name after studying seismic¹ events on the sea floor during such storms. They found that the shaking can last for several days and feel as strong as a magnitude² 3.5 earthquake.

The discovery was made by a research team led by Wenyuan Fan, a seismologist and professor at Florida State University. His team examined seismic and ocean records from September 2006 to early 2019 in an effort to identify possible stormquakes.

A report on the study was published in Geophysical Research Letters.

Intense³ energy from hurricanes and other severe storms can create very large waves in the ocean. These waves then “interact⁴” in some places with solid earth under the sea to cause “intense seismic source activity,” Fan said.

“We can have seismic sources in the ocean just like earthquakes within the crust⁵,” he added. “The exciting part is seismic sources caused by hurricanes can last from hours to days.”

The researchers found evidence of more than 10,000 stormquakes between 2006 and 2019 in coastal⁶ areas of the United States and Canada. Seismic activity was recorded off the coast of New England, as well as off of Florida and in the Gulf⁷ of Mexico. In Canada, evidence was found off the eastern provinces of Nova Scotia and Newfoundland, as well as British Columbia’s Pacific coast.

Stormquakes were found to have happened around continental⁸ shelves or sea floors containing flat land and at lower depths, the research showed.

The researchers considered other weather conditions when they tried to identify whether a seismic event could have been a stormquake. The seismic activity had to happen on a stormy day or have some other connection to a storm. Other seismic events, such as earthquakes, had to be ruled out as causes.

Even with evidence of so many stromquakes happening, it was not known until recently that such events even existed. This is mainly because scientists studying earthquakes have generally considered ocean-caused seismic waves as “background noise.”

The research found that major U.S. hurricanes had produced a lot of stormquakes. One example was Hurricane Bill, a storm that formed 10 years ago in the Atlantic Ocean. Bill strengthened into a Category 4 hurricane before weakening⁹ to a tropical¹⁰ storm and hitting Newfoundland. The researchers said the storm caused “numerous seismic events” off the northeast U.S. and Canadian coasts.

Other examples of stormquakes were 2008’s Hurricane Ike and Hurricane Irene in 2011. Ike led to stormquake activity in the Gulf of Mexico, while Irene caused seismic events off the coast of southern Florida.

The researchers noted¹¹ that not all hurricanes produce stormquakes. For example, the study found no evidence of stormquakes off the coast of Mexico. Also, no such activity was recorded in areas along the U.S. East Coast, starting in New Jersey¹², and continuing all the way down to Georgia.

The team noted that even Hurricane Sandy, one of the most costly¹³ storms in U.S. history, did not cause a single stormquake. Wenyuan Fan says this suggests that stormquakes are strongly influenced by the physical shape of the seafloor’s surface and seafloor conditions.

Fan added that there are still “lots of unknowns” about stormquakes. But he said discovering them “suggests we are reaching a new level of understanding of seismic waves.”

Fan said that he hopes the discovery will also lead to improved study methods for hurricanes, which in the past have mainly been observed from satellites in the sky.

“Now we are able to understand the phenomenon – or at least track part of its passage – through the solid earth as well,” he said.

I’m Bryan Lynn.

Words in This Story

magnitude – n. the size of something; the strength of an earthquake’s power

interact – v. act in such a way as to have an effect on something or someone else

source – n. a person, place or thing from which something comes

crust – n. hard, outer surface of something

exciting – adj. producing strong feelings

continental shelf – n. an area at the bottom of the sea near the coast of a continent, where the sea is not very deep

phenomenon – n. someone or something that is popular, especially because of an unusual ability or quality

track – v. to follow the progress of something

1 seismic   

a.地震的，地震强度的

参考例句：

• Earthquakes produce two types of seismic waves.地震产生两种地震波。
• The latest seismic activity was also felt in northern Kenya.肯尼亚北部也感觉到了最近的地震活动。

2 magnitude   

n.大小；重大；星等

参考例句：

• I want to know the magnitude of this equipment.我想知道这个设备的大小。
• I hadn't realized the magnitude of the problem.我没有认识到这个问题的重要性。

3 intense   

adj.认真的，专注的；强烈的；紧张的；热情的

参考例句：

• Susan was an intense young lady.苏珊是一个热情的年轻姑娘。
• The quarrel caused her intense unhappiness.争吵令她极其不快。

4 interact   

vi.相互作用，相互影响，互通信息

参考例句：

• All things are interrelated and interact on each other.一切事物互相联系并相互作用。
• The policeman advised the criminal to interact with the police.警察劝罪犯与警方合作。

5 crust   

n.(一片)面包皮，硬外皮，外壳；地壳

参考例句：

• This article focuses on radiation present in the earth crust.本文重点介绍源自地壳的辐射。
• Earth quakes can result from stresses in the earth's crust.地壳内的应力可能引起地震。

6 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。

7 gulf   

n.海湾；深渊，鸿沟；分歧，隔阂

参考例句：

• The gulf between the two leaders cannot be bridged.两位领导人之间的鸿沟难以跨越。
• There is a gulf between the two cities.这两座城市间有个海湾。

8 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。

9 weakening   

v.（使）削弱， （使）变弱( weaken的现在分词 )；消震

参考例句：

• The currency of that country is weakening on foreign exchanges. 那个国家的货币在外汇市场上疲软。 来自《现代汉英综合大词典》
• Bad and irregular eating was weakening every function of his body. 吃得又差又没有规律，使他身体的每一个官能都在衰退。 来自英汉文学 - 嘉莉妹妹

10 tropical   

adj.热带的，热带的，炎热的

参考例句：

• You must grow these tropical flowers in a glasshouse.你必须把这些热带花卉种在温室里。
• This disease is widespread in tropical areas.这种疾病在热带地区蔓延很广。

11 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

12 jersey   

n.运动衫

参考例句：

• He wears a cotton jersey when he plays football.他穿运动衫踢足球。
• They were dressed alike in blue jersey and knickers.他们穿着一致，都是蓝色的运动衫和灯笼短裤。

13 costly   

adj.昂贵的，价值高的，豪华的

参考例句：

• It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
• This dictionary is very useful,only it is a bit costly.这本词典很有用，左不过贵了些。