A tsunami warning was first declared for Chile and Peru, while a tsunami watch issued for Ecuador, Colombia, Antarctica, Panama and Costa Rica.
The warning was later extended to a Pacific Ocean-wide warning, covering all coastal areas on the Pacific Ocean except the west coast of the United States, British Columbia, and Alaska. Hawaiian media reported that tsunami warning sirens will be sounded at 6am local time.
A tsunami amplitude of up to 2.6 m (8.5 ft) high was recorded in the sea at Valparaiso, Chile. An amplitude of 2.34 m (7.68 ft) was recorded at Talcahuano in the Biobío Region.
An aftershock of 6.2 was recorded 20 minutes after the initial quake.Two more aftershocks of magnitudes 5.4 and 5.6 followed. The USGS said that "a large vigorous aftershock sequence can be expected from this earthquake".And indeed, four hours after the initial shock, at least 14 aftershocks larger than magnitude 5.5 had been recorded in an area stretching roughly 300 km north and south of the first epicenter. The largest of those aftershocks measured 6.9 .
In Juan Fernández Islands, situated in the Pacific Ocean about 667 km (414 mi) away from the coast of Chile, local residents reported "a wave of great size" in the main city, but it still remains unknown whether there is any damage.
Minor quakes generated by the main one could be felt as far as São Paulo, Brazil,located about 3,000 km (1,900 mi) away from Concepción.
http://en.wikipedia.org/wiki/2010_Chile_earthquake