Location: 11 km NNE of West Richland, Washington Period: 12 May 2009 03:21:45 - 20 May 2009 12:37:57 (8 days 9 hours 16 minutes) Volcanoes in 100km radius: None Earthquakes: 221 3 swarms found nearby. 2009 S20090308.1(0.9km) 7 Mar 23 days 2 hours 494 earthquakes S20090403.1(1.5km) 2 Apr 13 days 17 hours 278 earthquakes 2011 S20110904.1(1.9km) 4 Sep 3 days 13 hours 47 earthquakes