Method for determining geometric characteristics of a hydraulic fracture includes performing a baseline seismic survey for a geological formation. A velocity model is created by combining results of the baseline seismic survey and additional geoscientific information, and seismic properties of the geologic formation are evaluated. At least one strong flat lithological reflector disposed below a planned fracture is identified. A numerical model of elastic wave propagation in the geologic formation with a fracture with given properties is created. Hydraulic fracturing is performed and after fracturing when the fracture is maintained open and pressurized seismic surveys are performed. The fracture's dimensions and shape are determined by comparing the first and the second reflected and refracted seismic signals and solving an inverse problem with the use of the numerical model.