Microseismic monitoring is a very useful tool to evaluate hydraulic fracture in wells, especially in horizontal drilling in unconventional reservoirs. In Lindero Atravesado field, Neuquén Basin, Argentina, two horizontal wells were drilled and stimulated at the same stratigraphic level in Vaca Muerta Formation in June 2019. The hydraulic fracture treatments were monitored with full coverage surface microseismic array. The data acquired was processed to locate event hypocenters and to evaluate focal mechanisms and stress regime. Results present several interesting observations about the fracking and the interaction of the treatment with a nearby, previously completed producing well. Additionally, events location distribution was employed to calibrate frac simulators and optimize future wells’ spacing and fracture strategies. In this paper we will show acquisition, processing, and interpretation of these useful results.