Rescue teams act after Ya'an quakes

Four dead, 41 injured as pair of temblors felt as far away as Chengdu, Chongqing

Twenty-eight medical and epidemic prevention experts from Sichuan province are aiding residents of Ya'an after a pair of earthquakes struck the region on Wednesday, killing four, according to the provincial health commission.

A magnitude 6.1 quake hit Lushan, a county under the administration of Ya'an, at 5 pm. Three minutes later, a magnitude 4.5 earthquake was felt in Baoxing, another county in Ya'an, according to the China Earthquake Networks Center.

The quakes left four people dead and 41 injured, with one in critical condition as of Thursday, said Ya'an Vice-Mayor Gong Bing during a news conference. The wounded were being treated at the Ya'an municipal and Baoxing county hospitals, he said.

Located in western Sichuan and known as a giant panda habitat, Ya'an has many mountains. According to the general office of the Ya'an municipal committee of the Communist Party of China, the four who died were killed by falling stones.

Soon after the two quakes, the Sichuan provincial health commission deployed 28 medical and epidemic prevention experts to Ya'an from the West China Hospital of Sichuan University, Sichuan Provincial People's Hospital, Sichuan Provincial Orthopedic Hospital and the Sichuan Center for Disease Control and Prevention. The experts are members of three national-level emergency rescue teams and a provincial-level post disaster epidemic prevention team.

Headed by Shen Hai, president of Sichuan Provincial Orthopedic Hospital, the National (Sichuan) Traditional Chinese Medicine Emergency Medical Rescue Team from the hospital arrived at the Lushan county medical center at 9:48 pm on Wednesday.

The Sichuan Earthquake Administration attributed the Lushan temblor on Wednesday to an aftershock of an earthquake that hit the county on April 20, 2013, killing 196 people and injuring 12,614. The administration denied the possibility of a larger aftershock in the near future.

Tremors were felt as far away as Sichuan's capital Chengdu, which is about 109 kilometers away from the epicenter of the Lushan earthquake, and the province's neighboring Chongqing municipality, which is about 435 km away from the epicenter.

To help prevent casualties, a real-time early warning system that shows alerts on TVs and mobile phones has been established by the Institute of Care-Life in Chengdu.

Twenty-nine seconds before seismic waves from the Lushan earthquake arrived, people in high-rise buildings in the Chengdu Tianfu Software Park received early warnings, according to Wu Liangyan, an information officer with the institute.

Furthermore, residents in various parts of Chongqing received early warnings between 26 and 38 seconds in advance, she said.

The system sends warnings seconds after a quake is detected and can help save lives because the warnings are transmitted via radio waves, which are able to travel faster than seismic waves－300,000 km per second, compared to 3 to 6 km/s for a seismic shock.

Chen Huizhong, a senior research fellow with the China Earthquake Administration's Institute of Geophysics, said this means people nearby have a chance to escape before they even feel the quake.