The quake—measured by China's seismological bureau at magnitude-7 and the U.S. Geological Survey at 6.6—struck the steep hills of Lushan county shortly after 8 a.m. toppling buildings, many of them older brick structures. Tiles fell from roofs, and pictures dropped from walls, sending people into the streets in their underwear and wrapped in blankets.
"Generally the quake felt much stronger than that from five years ago. Many decorations at home got smashed," said Zhao Zheng, a resident of Ya'an city, near the quake. He was reached by direct message on his Twitter-like microblog resident and said he was awakened by the earthquake.
The People's Daily newspaper said 41 people had been killed, including at least 28 in the epicenter of Lushan. Xu Mengjia, Communist Party secretary for Ya'an, which administers Lushan, told China Central Television that at least 32 people had been killed and more than 600 injured.
The quake's shallow depth, less than 13 kilometers (8 miles), likely magnified the impact. The official Xinhua News Agency said that the quake rattled buildings in the provincial capital of Chengdu 115 kilometers (70 miles), to the east. It caused the shutdown of the city's airport for about an hour before reopening, state media said.
Lushan, where the quake struck, is home to 1.5 million people where the fertile Sichuan plain meets foothills that eventually rise to the Tibetan plateau. Known for its mountains, the area is near a well-known preserve for pandas.
Social media users who said they were in Lushan county posted photos of collapsed buildings and reported that water and electricity had been cut off.
A man who answered the phone at the Ya'an city government said telecommunications were cut and that medical and rescue teams are on the way to the area. Xinhua said more than 2,000 soldiers were being mobilized and sent to the disaster area.
"I felt the strong quake this morning in my office. All drawers of the desk opened and some stuff on the table fell on the floor," said the man, who refused to give his name, as is usual with low-ranking Chinese government officials.
The area lies near the same Longmenshan fault where the devastating 7.9-magnitude quake struck May 12, 2008, leaving more than 90,000 people dead or missing and presumed dead.
"It was just like May 12," said Liu Xi, a writer in Ya'an, who was jolted awake by Saturday's quake. "All the home decorations fell at once, and the old house cracked."