美国国家公共电台 NPR--How the Salton Sea may be delaying California's next giant earthquake

How the Salton Sea may be delaying California's next giant earthquake

Transcript¹

Southern California's Salton Sea is drying up and that may be delaying the region's next big earthquake. Researchers say the lack of water is reducing stress on the San Andreas fault.

A MART?NEZ, HOST:

The Salton Sea in Southern California is not a sea. It's the state's largest lake. And it might be delaying the region's next giant earthquake. That's right, possibly delaying the big one. That's according to a study just out in the journal Nature. The Lake may be helping² to keep stress off the southern portion of the San Andreas Fault, one of the world's largest faults. Joining us now for more on the study is reporter Erik Anderson with member station KPBS in San Diego. So Erik, let's start by giving us a sense of where the Salton Sea is, how it came to be and why it's so important to seismologists.

ERIK ANDERSON, BYLINE³: Yeah, it's located just north of Mexico, about 130 miles east of San Diego. The current lake was created by agricultural runoff after a berm broke back in 1905. Now, the Earth's crust is pretty thin here, which allows for plenty of geothermal energy - that's underground heat that can be tapped - and lots of small earthquakes. There have been just under a thousand measurable earthquakes in the past month, most of them, of course, too small to feel.

MART?NEZ: And I'm guessing the San Andreas Fault has a lot to do with that.

ANDERSON: Yeah, it's at the southern end of that 800-mile-long San Andreas Fault. Now, the fault line, you might know, is famous for generating the damaging San Francisco earthquake back in 1906 and the Loma Prieta quake in 1989. Scientists fear that the next big rupture⁴ generated here at the southern end could be strong enough to send multiple damaging shockwaves through the Los Angeles Basin. That's a region where more than 14 million people live.

MART?NEZ: And the study out in the journal Nature shows a connection between the size of the lake and its impacts on seismic⁵ activity. Tell us about that.

ANDERSON: Yeah, the study's author, Ryley Hill, says that geological research allowed them to build a computer model that links the strong ruptures⁶ over time to times when the valley was filled with water. The Colorado River has filled this valley about six times over the past thousand years. And at times, the lake has held up to 30 times more water than the current sea does. Now, the weight of that water pushes down on the Earth's crust. And it lubricates the faults, boosting chances for a big quake. And Hill says, now that the Salton Sea is shrinking because of drought and less agricultural runoff, that means there is less pressure on the volatile⁷ southern tail of this earthquake fault system.

RYLEY HILL: It's a section that is currently locked. And it's been locked for 300 years, OK? Now, the last major rupture was in 1725. And over the past 1,000 years, we've actually had probably six or seven large events.

ANDERSON: Scientists are puzzled why there hasn't been a major earthquake here in the last 300 years. Historical records show that one should have happened every 180 years or so. A smaller lake does help ease pressure on the fault.

MART?NEZ: The thing is, though, Erik, I mean, this is Southern California we're talking about here. This is an area that's primed for a quake. A lot of pent-up energy there - that's got to worry seismologists.

ANDERSON: Yeah, Hill and others say that the longer the region goes without a major event, more seismic stress does build up. And that increases the chances that the next big earthquake on the southern San Andreas fault could be the big one. But scientists also caution that the size of the lake in the Salton trough is only one factor that influences seismic activity. There are many others.

MART?NEZ: That's reporter Erik Anderson with KPBS in San Diego. Erik, thanks a lot.

ANDERSON: My pleasure.

(SOUNDBITE OF KINACK SONG, "SHINE")

1 transcript   

n.抄本，誊本，副本，肄业证书

参考例句：

• A transcript of the tapes was presented as evidence in court.一份录音带的文字本作为证据被呈交法庭。
• They wouldn't let me have a transcript of the interview.他们拒绝给我一份采访的文字整理稿。

2 helping   

n.食物的一份&adj.帮助人的，辅助的

参考例句：

• The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
• By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。

3 byline   

n.署名；v.署名

参考例句：

• His byline was absent as well.他的署名也不见了。
• We wish to thank the author of this article which carries no byline.我们要感谢这篇文章的那位没有署名的作者。

4 rupture   

n.破裂；(关系的)决裂；v.(使)破裂

参考例句：

• I can rupture a rule for a friend.我可以为朋友破一次例。
• The rupture of a blood vessel usually cause the mark of a bruise.血管的突然破裂往往会造成外伤的痕迹。

5 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。

6 ruptures   

n.（体内组织等的）断裂( rupture的名词复数 )；爆裂；疝气v.（使）破裂( rupture的第三人称单数 )；（使体内组织等）断裂；使（友好关系）破裂；使绝交

参考例句：

• Fault ruptures may consist of a single narrow main break. 断层破裂可能只包括单独一条狭窄的主裂隙。 来自辞典例句
• The dry seed ruptures and the green leaf uncurls. 干瘪的种子裂开了，卷曲的绿叶伸展了。 来自辞典例句

7 volatile   

adj.反复无常的，挥发性的，稍纵即逝的，脾气火爆的；n.挥发性物质

参考例句：

• With the markets being so volatile,investments are at great risk.由于市场那么变化不定，投资冒着很大的风险。
• His character was weak and volatile.他这个人意志薄弱，喜怒无常。