VOA科学技术2023--GPS Data Could Predict Earthquakes Hours Ahead

GPS Data Could Predict Earthquakes Hours Ahead

Researchers say they have identified earth movement signals that could predict earthquakes up to two hours before they hit.

The signals were recorded, or detected, by GPS collection devices. The devices were positioned in areas where major earthquakes had struck in the past.

Scientists noted¹, however, that the right equipment does not currently exist to use the data to predict earthquakes. But if the sensitivity of current GPS measuring devices can be improved, the researchers say a new earthquake warning system could be possible.

Earthquakes are caused by movements, or slips, in existing faults under Earth's surface, the U.S. Geological Survey (USGS) explains. A fault is a long break in rock attached to Earth's crust. When tension builds up along a fault, energy waves are released and travel through the crust. This causes the ground to shake.

Technology for predicting earthquakes currently remains² very limited. But the USGS does have equipment that can pick up seismic³ data when an earthquake is just starting. The term seismic relates to earthquake activity.

The USGS method makes it possible to warn people in areas where seismic activity is expected. But this method generally can only provide a warning several seconds before an earthquake hits. The USGS system is called ShakeAlert. It has already been deployed⁴ along the U.S. West Coast. That is where the majority of earthquakes happen in the country.

But the new detection method could produce warnings up to two hours before the damaging effects of an earthquake are felt. Such a system could save lives by giving people the chance to get out of buildings that might collapse⁵ in an earthquake.

Two scientists from France's National Research Institute for Sustainable Development carried out a study that described the latest results. The findings recently appeared in the publication Science.

For the study, researchers examined GPS data collected before and after past earthquake events around the world. The data was collected on 90 earthquakes measuring larger than 7 on the Richter scale. The study period covered the past 20 years.

The team identified a pattern of fault movements as they examined the data collected from different areas. The movement signals were recorded within two hours of an earthquake striking. The researchers said the study demonstrates that faults generally begin to move about two hours before a large earthquake.

Scientists had identified such signals before single earthquakes in the past. But until now, researchers were not able to link those signals to all seismic events.

While the data identified this pattern, the scientists said the instruments that could capture GPS data in real time do not currently exist.

The National Research Institute for Sustainable Development issued a statement on the development. It said that in order to make predictions, researchers "would need to measure signals at least 10 times smaller than what we can presently do."

Another way to possibly build a better earthquake prediction system would be to develop "dense⁶ measurement networks" that sit very close to faults. However, such an effort would require major technological⁷ progress, the institute said.

Quentin Bletery is a geophysicist at Côte d'Azur University in the city of Nice. Bletery worked together on the study with Jean-Mathieu Nocquet, another researcher at the university.

Bletery told Science that the study found that no observable movement was identified in the first 46 hours leading up to an earthquake. But starting around two hours before an earthquake, the GPS signals recording⁸ movement started to increase.

To confirm its findings, the team compared that data to more than 100,000 random⁹ time periods recorded when no earthquakes were reported. That experiment found that similar patterns in non-earthquake areas happened just 0.03 percent of the time.

"This tells us earthquakes are predictable in nature," Bletery told Science.

The scientists note that more research is needed to support their findings. Much of the information used in the latest study, for example, depended heavily on data from GPS stations near major earthquake sites.

Words in This Story

GPS – n. a system that follows the movements of something with an electronically-powered piece of equipment

pattern – n. a regular and repeated way in which something happens

resolution – n. a measure of the sharpness of an image or the fineness a device operates at

1 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。

2 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

3 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。

4 deployed   

（尤指军事行动）使展开( deploy的过去式和过去分词 )； 施展； 部署； 有效地利用

参考例句：

• Tanks have been deployed all along the front line. 沿整个前线已部署了坦克。
• The artillery was deployed to bear on the fort. 火炮是对着那个碉堡部署的。

5 collapse   

vi.累倒；昏倒；倒塌；塌陷

参考例句：

• The country's economy is on the verge of collapse.国家的经济已到了崩溃的边缘。
• The engineer made a complete diagnosis of the bridge's collapse.工程师对桥的倒塌做了一次彻底的调查分析。

6 dense   

a.密集的，稠密的，浓密的；密度大的

参考例句：

• The general ambushed his troops in the dense woods. 将军把部队埋伏在浓密的树林里。
• The path was completely covered by the dense foliage. 小路被树叶厚厚地盖了一层。

7 technological   

adj.技术的；工艺的

参考例句：

• A successful company must keep up with the pace of technological change.一家成功的公司必须得跟上技术变革的步伐。
• Today,the pace of life is increasing with technological advancements.当今， 随着科技进步，生活节奏不断增快。

8 recording   

n.录音，记录

参考例句：

• How long will the recording of the song take?录下这首歌得花多少时间？
• I want to play you a recording of the rehearsal.我想给你放一下彩排的录像。

9 random   

adj.随机的；任意的；n.偶然的(或随便的)行动

参考例句：

• The list is arranged in a random order.名单排列不分先后。
• On random inspection the meat was found to be bad.经抽查，发现肉变质了。