Earthquake history graphs (10/27/09):

Temporal history of earthquake activity in the vicinity of the Blanco Transform, 30 March - 6 April 2008.  Black line shows the cumulative number of earthquakes located by SOSUS, with an average rate of ~120 events/day observed during the initial four days of the swarm. Stem plot indicates the acoustic source level (dB re 1μPa @ 1m) of each event.  Data shown related to activity associated with the intraplate swarm Earthquakes having magnitudes Mw ≥ 5 are identified.