Location: 13 km NNE of West Richland, Washington Period: 7 Mar 2009 08:52:40 - 30 Mar 2009 11:20:36 (23 days 2 hours 27 minutes) Volcanoes in 100km radius: None Earthquakes: 494 3 swarms found nearby. 2009 S20090403.1(1.2km) 2 Apr 13 days 17 hours 278 earthquakes S20090512.1(0.9km) 12 May 8 days 9 hours 221 earthquakes 2011 S20110904.1(1.1km) 4 Sep 3 days 13 hours 47 earthquakes