Four people were killed and 14 others were injured as of 7:40 pm on Wednesday after two earthquakes struck Ya'an, Sichuan province.

A magnitude-6.1 earthquake hit Lushan, a county under the administration of Ya'an, at 5 pm on Wednesday according to the China Earthquake Networks Center.

The epicenter, with a depth of 17 km, was monitored at 30.37 degrees north and 102.94 degrees east, the center said.

Three minutes later, a magnitude-4.5 earthquake with a depth of 18 km was observed Baoxing, another county under the administration of Ya'an, at 5:03 pm.

Its epicenter was monitored at 30.37 degrees north and 102.92 degrees east.

People in Chengdu, capital of Sichuan, and the province's neighboring Chongqing municipality felt the tremor from Lushan.

Between 26 and 38 seconds before seismic waves arrived, people in different parts of Chongqing received an early warning, according to Wu Liangyan, an information officer with the Institute of Care-Life in Chengdu.

A real-time early warning system running on TV sets and mobile phones, which people can make use of in case of an earthquake, has been installed by the institute.

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 kilometers per second, compared to 3 to 6 km per second 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.

With a great deal of mountainous terrain, Sichuan is prone to earthquakes.

According to the Sichuan Earthquake Administration, the Lushan earthquake on Wednesday was an aftershock of the Lushan earthquake that killed 196 people and injured 12,614 on April 20, 2013.

The epicenter of the 2013 quake is in Longmen, 9 km away from Wednesday's earthquake.