Forces unleashed by the earthquake opened a large crack in the expressway from Songpan county to Jiuzhaigou county. PHOTO BY FAN PEIKUN / XINHUA AND FENG ZHENG / CHINA NEWS SERVICE

The Canadian woman is expected to be discharged in two or three days, doctors said. "We have received excellent care. The rescue workers and doctors have been very helpful," she said.

About 500 medical workers from all across the province have been providing emergency treatment.

No buildings collapsed in the quake, but some 1,680 houses were damaged, according to the provincial government.

Rescue forces including Armed Police and the PLA Ground Force were busy clearing roads and distributing relief materials, such as tents.

Also on Wednesday morning, a magnitude-6.6 earthquake struck the Xinjiang Uygur autonomous region, injuring 32 in Jinghe county, Bortala Mongolian autonomous prefecture. The China Earthquake Administration said the two quakes are not related and they do not mean China has entered a period of active seismic activities.

The number of earthquakes on the Chinese mainland is still within normal range, officials said.

Xinhua contributed to this story.