The 6.4 magnitude jolt was the strongest of the thousands of aftershocks that have rocked the region since the initial quake left more than 88,000 people dead or missing.
The latest shaking occurred at 4:21 p.m. local time and wrecked an additional 860 houses while also inflicting damage to 3,100 others, provincial officials said.
The quake sent people fleeing from buildings across southwestern China and caused high-rise buildings to sway as far away as the capital, Beijing.
Landslides caused by the recent string of strong seismic events have triggered landslides that have blocked rivers, creating a mounting threat of floods.
Engineers and the military worked around the clock, using dynamite and large machinery in an attempt to remove blockages without threatening downstream residents with a sudden release of water.
