The US Geological Survey (USGS) reported the quake at 11:16 p.m. Argentina time at a depth of about 10.8 kilometers (6.7 miles).
The epicenter was located in the Drake Passage, the body of water between the southern tip of South America and Antarctica.
Tremors were felt in several cities across Chile and Argentina, but there were no immediate reports of damage.
Chile’s Navy Hydrographic and Oceanographic Service (SHOA) issued a tsunami warning and ordered evacuations of coastal areas after the quake.
The Chilean government also cautioned that tsunami waves could affect its Antarctic bases.
The Pacific Tsunami Warning Center later confirmed the risk had eased, saying any waves were unlikely to exceed 0.3 meters (1 foot).
The USGS initially measured the quake at magnitude 8.0 before revising it to 7.5.