(Adds no tsunami threat, details on quake's location off coast)
March 16 (Reuters) - A magnitude 7.0 earthquake hit off the northern coast of Chile at a depth of 21 miles (32 km), the U.S. Geological Survey said on Sunday.
The quake was centered 40 miles (64 km) northwest of Iquique, the USGS said. The Pacific Tsunami Warning Center said there was no tsunami expected.
Chilean authorities said they ordered a preventive evacuation of part of the northern coastline after the quake.
There were no immediate reports of injuries or damage.
(Reporting by Peter Cooney; Additional reporting by Alexandra Ulmer in Santiago; Editing by Jim Loney)