The earthquake hit Changning County of Yibin at 10:55 p.m. Monday (Beijing Time), according to local authorities.
The epicenter, with a depth of 16 km, was monitored at 28.34 degrees north latitude and 104.90 degrees east longitude, according to the China Earthquake Networks Center.
Most of the deaths were caused by damaged houses, according to rescuers.
Fifty-three people are receiving treatment in two hospitals in Changning. Among them, two are in critical conditions and six others are severely injured.
The Ministry of Emergency Management has activated an emergency response and sent a work team to the stricken areas to provide guidance in rescue and disaster relief.
The ministry and the National Food and Strategic Reserves Administration have dispatched 5,000 tents, 10,000 folding beds and 20,000 quilts to the quake-hit areas.
A team of rescuers sent by Red Cross Society of Sichuan Province arrived in Shuanghe township of Changning at about 4 a.m. Tuesday.
As of 1 a.m. Tuesday, the quake has caused a major highway connecting Yibin and Xuyong County of Sichuan’s Luzhou City to be closed. Some sections of other roads have also been blocked or closed.
In the provincial capital Chengdu, an early warning system alarmed the public through multiple broadcasting systems about one minute before the earthquake struck. The same system alerted residents in Yibin ten seconds before the quake hit.
The early warning system uses the theory that radio waves travel faster than seismic waves.
Earthquake research has found that being aware of an earthquake three seconds beforehand can save 14 percent of casualties, 10 seconds can save 39 percent of casualties, and 20 seconds can save 63 percent of casualties.
A 5.3-magnitude earthquake rattled Changning County at 7:34 a.m. Tuesday, according to the China Earthquake Networks Center (CENC).
The epicenter was monitored at 28.37 degrees north latitude and 104.89 degrees east longitude, the CENC said in an initial report.
