Rescuers carry a child to the ambulance in Changning county, Southwest China's Sichuan Province on Tuesday. A 6.0-magnitude earthquake struck Changning late Monday and has claimed 13 lives so far. Photo: VCG

An early warning system provided residents in Southwest China's Sichuan Province life-saving seconds to prepare for an earthquake on Monday that killed at least 13 people and injured 199. 

The epicenter of the 6.0-magnitude earthquake, with a depth of 16 kilometers, was monitored at 28.34 degrees north latitude and 104.90 degrees east longitude in Changning county, the China Earthquake Networks Center (CENC) reported.

Chinese President Xi Jinping ordered Tuesday full efforts in relief and rescue work to ensure the safety of people's lives and property. 

The Ministry of Emergency Management and the National Food and Strategic Reserves Administration sent 5,000 tents, 10,000 folding beds and 20,000 quilts to quake-hit areas, the Xinhua News Agency reported on Monday. 

After the earthquake, amid nationwide prayers for the victims, Chinese social media also focused on the early warning system. 

Chinese media reported that China is the third country after Japan and Mexico to boast such an advanced level of earthquake warning ability. The system covers 31 provinces and municipalities and has issued 40 earthquake warnings via television, cellphone, broadcasts and other terminals. There have been no false alarms so far.

Effective warning 

"I jumped out of my sofa after I felt the house violently shaking and I ran immediately downstairs with other residents of the building," said Gao Feng, a resident in Changning county. Many old buildings in his neighborhood were destroyed by the earthquake and there were several aftershocks, he said.

Chengdu resident Tang Jiayou told the Global Times that he received the warning while watching television Monday night. 

"It flashed on the television screen, with a countdown saying how long it would take for the seismic waves to arrive. But it took me a few seconds to realize this, because I haven't seen this before," he said. 

Residents of Chengdu, the Sichuan provincial capital, about 300 kilometers from Changning, received the alert 61 seconds before the seismic waves arrived.  

People from 180 schools and 101 communities were evacuated after receiving the early warning, Wang Tun, head of the Institute of Care-life, a key earthquake early warning laboratory in Chengdu, told the Global Times.

The warning system was developed by Wang's institute and emergency management departments in the wake of the devastating 2008 Wenchuan earthquake, which claimed more than 69,000 lives. Wenchuan is 499 kilometers from Changning.

The system warned government departments, communities and other places via cellphone, television and other broadcasts, Wang said. 

Loudspeakers have been installed for earthquake warnings in 60 communities in Chengdu. Residents of Chengdu High-tech Industrial Development Zone had a 60-second countdown, Wang said. 

Research has found that being aware of an earthquake even three seconds before it hits can save 14 percent of casualties, and 20 seconds can save 63 percent, Xinhua said. 

A similar system alerted residents in Yibin 10 seconds before the quake, according to media reports. Yibin is 46 kilometers away from Changning. 

However, an anonymous expert at China Earthquake Administration said such a warning is of a more limited use. People near the epicenter cannot receive the warning as there's not enough time, he said, noting that the farther people are away the less the impact and the less need for a warning. 

Wang Haitao, director of CENC, said at a Tuesday conference that China's earthquake warning is still in its infancy. China intends to invest 1.87 billion yuan ($0.28 billion) to build observation points in earthquake areas such as northern China and Southwest China's Sichuan and Yunnan provinces. 

Experts suggested that government enhance residents' awareness of disaster prevention and mitigation. 

After the 2008 Wenchuan earthquake, many Sichuan people are more experienced in dealing with earthquakes, thanks to information distributed on the internet and from the government, said Chengdu resident Chen Zhuo. 

Some even have emergency kits in their houses, he noted. 

Cause of disaster 

Seismologists said Sichuan and neighboring areas experience frequent earthquakes as they are situated at the edge of a quake-prone region where active seismicity occurs due to a collision between two tectonic plates. 

Excessive exploitation of shale gas in the area may have contributed to the earthquake, some internet users argued.

Wang said at Tuesday's conference that there's no sufficient evidence to indicate that the earthquake has anything to do with shale gas mining. 

The mining usually goes as deep as 1,000 meters, but the epicenter of this earthquake reached a depth of 16 kilometers, which suggests that human activities have a limited impact, Guo Xun, a seismologist with the China Earthquake Administration, told the Global Times on Tuesday.

He said that this causality became a concern after US scientists found that smaller earthquakes increased in areas near oil extraction and shale gas exploitation. But this connection has not been proving by concrete scientific evidence.

In February, about 1,000 residents gathered at a government building in Rongxian county in Sichuan, after two people died in two days during two earthquakes measuring 4.3- and 4.9. They suspected the earthquakes were caused by shale gas mining, but Chinese seismologists said there was insufficient evidence to support the claim.