Earthquake Summary
Felt Reports
Damage reported at Rancagua. A small tsunami was recorded with wave heights (peak-to-peak) of 16 cm at Valparaiso and 29 cm at San Antonio.
Tectonic Summary
The Chile earthquakes of March 11, 2010, 14:39 UTC and 14:55 UTC, occurred in the region of the plate boundary between the Nazca and South America plates, in the aftershock region of the great Chile earthquake of February 27, 2010. The March 11 earthquakes almost certainly occurred as the result of the change of regional stress caused by the February 27 earthquake. Preliminary analyses of their locations and seismic-wave radiation patterns, however, imply that the March 11 shocks occurred as the result of normal faulting within the subducting Nazca plate or the overriding South America plate, unlike the February 27 earthquake, which occurred as thrust faulting on the interface between the two plates. At present, the focal depths of the shocks are not known with sufficient precision to confidently determine within which of the Nazca or South America plate the earthquakes occurred.
Earthquake Information for Chile
Earthquake Information for South America
Sebastián Piñera 
A magnitude 6.9 earthquake struck Chile on Thursday, just 21 minutes before the country's new president, Sebastián Piñera, was due to be sworn in. This earthquake comes several days after a heavy 8.8 magnitude earthquake shook the country, the strongest one in almost half a century.

According to the US Geological Survey, the quake's epicentre was 
135 kilometres (85 miles) south of Valparaiso, where the presidential inauguration took place, and 145 kilometres (90 miles) southwest of capital Santiago. Later, it was reported that the epicenter was offshore Pichilemu, a coastal town in the O'Higgins Region.

The Miami Herald reports that the temblor was among seven aftershocks. There were no reports of damage, injuries, or deaths, although some residents rushed outside after the tremors.

According to reports by the Associated Press, the Chilean navy called for a tsunami alert and encouraged residents living along shorelines to move to higher ground; however, the Pacific Tsunami Warning Center commented that "a destructive Pacific-wide tsunami is not expected."