Photo:CENC

The 4.8-magnitude earthquake that occurred in Wenchuan county, Southwest China's Sichuan Province, late Wednesday was the aftershock of the 2008 Wenchuan Earthquake, experts said. 

The 4.8-magnitude earthquake hit Wenchuan at 11:36 pm on July 14, with a focal depth of 15 kilometers, according to the China Earthquake Networks Center. No casualties were reported. 

The epicenter of the 2008 Wenchuan Earthquake has a tendency to expand southwest and the one that hit Wenchuan on Wednesday was the aftershock of 2008 Wenchuan Earthquake, Wang Yunsheng, a professor from Chengdu University of Technology, told Chinese media Fengmian news. 

Sichuan Earthquake Administration also confirmed that the 4.8-magnitude earthquake in Wenchuan was an undulating activity in the Wenchuan aftershock region. 

Since 1970, 120 earthquakes of magnitude 4.0 and above have occurred within 50 kilometers of the epicenter of this 4.8 earthquake. Among them, there were 100 earthquakes of magnitude 4.0-4.9, 15 earthquakes of magnitude 5.0-5.9, four earthquakes of magnitude 6.0-6.9, and one earthquake of magnitude 8.0 - the one that happened in 2008, the administration said. 

Sun Shihong, a researcher of China Earthquake Networks Center, told the Global Times on Thursday that it's possible for an earthquake to last for 13 years as long as the earthquake's undulating activities in one place have seen an ongoing trend. Some earthquake aftershocks may last for decades, even longer.

Sun said after the deadly earthquake in 2008 and years of aftershocks, a bigger magnitude earthquake is unlikely because energy release of the land plate where Wenchuan is located has basically ended and so has the seismic activities.  The plate is called Bayan Har. There has been at least five major earthquakes, and the 2008 Wenchuan Earthquake is one of them and also the one in Yushu, Qinghai Province, in 2010.

Wang said they will be on the lookout for more aftershocks.

Chengdu, about 76 kilometers away from the epicenter, felt the quake.

A resident living in Chengdu's Jinhua district said that he broke his porridge bowl when the earthquake hit the Wenchuan county. Some videos posted online showed the ceiling lamp at a resident in Chengdu shook for seconds. Some communities organized residents to escape.