 This subbasin is in the vicinity of the seismically active Greenville Fault associated with the Diablo Range.In fact the name of the second segment of the Greenville Fault (starting from north to south) is the Arroyo Mocho Segment.The Arroyo Mocho Segment is generally considered to be more well developed and not as youthful as traces delineating the Marsh Creek-Greenville Segment, for example.