Complex sentence: The 2009 Costa Rica earthquake was a 6.1 M w earthquake that struck on January 8,2009, at 01:21:34 p.m. local time (6:21:34 p.m. UTC) in northern Costa Rica, NNW of San José.
Split into simpler sentences: The 2009 Costa Rica earthquake occurred at 01:21:34 p.m. local time (6:21:34 p.m. UTC) on January 8,2009. The epicenter of the 6.1 M w earthquake was in northern Costa Rica, north-northwest of San José.