Microseismicity was monitored in the Chaveroo oil field in southeastern New Mexico during, and for 5 weeks following, a pressurized stimulation of a well being prepared as an injector for a water flood operation. Three-thousand barrels of water were injected into the reservoir over a 5.5-hour period. Little seismicity was detected during the stimulation. Intermittent monitoring over a 5-week period following the injection indicated detectable seismicity occurring with activity levels varying in time. The most active period recorded occurred just after production resumed in the immediate area of the monitor well. Mapping the microearthquakes using the hodogram technique indicates the events occur along linear trends which corroborate known structural trends of the field. Seismicity trends were defined both parallel and perpendicular to the regionally defined maximum horizontal stress direction. Seventy-three good quality events were recorded, in a cumulative 24 hour period, from which structures were mapped up to 3000 ft from the monitor well. 13 refs., 9 figs.