Figure 2. (a) Vertical seismic section parallel to the azimuth of a treatment well monitored for microseismic activity (courtesy of Seitel Inc.); (b) Same seismic line overlaid by microseismic events from a stage interpreted as associated with a fault reactivation. Microseismic events align very well and depict the trace for an antithetic normal fault verging opposite to the inclination of the reflectors, beds and horizontal well.