The U.S. Geological Service says the quake's epicenter was 80 miles (130 kilometers) southeast of Santiago del Estero, a provincial capital of 250,000 people and the 12th-largest city in Argentina.
It was centered deep underground, nearly 400 miles (600 kilometers) below the surface, where quakes generally cause less damage.
The shaking prompted people to spill out of the San Isidro courts building in Buenos Aires province Friday morning.
