Another big aftershock off Chile's northern coast

SANTIAGO, Chile - USGS says powerful 7.8-magnitude aftershock rocks Chile's northern coast, a day after an 8.2 quake.

It caused buildings to shake in the port of Iquique, which saw some damage from the big quake on Tuesday. There are no immediate reports of new damage or injuries.

The latest tremor came 45 minutes after a strong 6.4-magnitude aftershock shook the same area.

The stronger aftershock's epicenter was 14 miles (23 kilometers) south of Iquique. The USGS said the aftershock had a depth of 12 miles (20 kilometers).

Officials say there is no threat of tsunami to U.S. coastal states in the Pacific from the aftershock.