Three major earthquakes of magnitudes 5.8, 6.0 and 5.2 jolted Caodeng township in Barkam, capital of the Aba Tibetan and Qiang autonomous prefecture in Sichuan province early on Friday morning.
Eleven earthquakes of magnitude-3.0 and above had been monitored, with the epicenter in Caodeng. One person was injured and no deaths were reported, according to the Sichuan provincial department of emergency management.
After the earthquakes, the Sichuan Provincial Earthquake Relief Headquarters quickly implemented a Level 3 response to geological disasters, and the Sichuan provincial department of emergency management dispatched five emergency rescue teams with a total of 1,314 people to the quake zone.
Forty resettlement sites had been set up in five towns and townships near the epicenter, 13 emergency shelters had been opened, and 25,790 people had been urgently relocated, the department said.
The earthquakes triggered a Level 4 emergency response from the Ministry of Emergency Management.
Minister Huang Ming, who is investigating a recent deadly building collapse in the Hunan provincial capital Changsha, gave instructions immediately after the jolts.
China has a four-tier emergency response system, with Level 1 representing the most severe response.
Aside from dispatching rescuers, Huang also demanded all-out efforts to ensure the basic living needs of people in affected areas are met. Measures should also be rolled out to prevent secondary disasters, he said.
The work group from the ministry left for the earthquake-stricken area in the small hours of Friday morning, the ministry said.
Mountainous Sichuan is prone to incessant earthquakes. On June 1, a magnitude-6.1 earthquake shook Lushan county. On May 20, a magnitude-4.8 earthquake hit Hanyuan county. On April 6, a magnitude-5.1 earthquake struck Xingwen county.
According to the Sichuan Earthquake Administration, the Lushan earthquake on June 1 was an aftershock of the Lushan earthquake that killed 196 people and injured 12,614 on April 20, 2013.
The magnitudes 5.8 and 6.0 earthquakes in Barkam on Friday were the fourth and fifth destructive earthquakes the province had experienced this year, said Wang Tun, head of the Institute of Care-Life in Chengdu, capital of Sichuan.
Six seconds after the magnitude-6.0 earthquake, a real-time early warning system developed by the institute said that seismic waves would reach Chengdu 66 seconds later.
In many parts of China, the real-time early warning system already runs on TV sets and mobile phones, which people can use in case of an earthquake.
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 at 300,000 kilometers per second, while seismic shock waves travel at only 3 to 6 km/s.