Phase variation of potential field data can be used as an interpretation method. This idea appears in edge detection with tilt angle or phase angle. The advantages of this quantity are its independency to body magnetization direction and also its easy computations. In this paper variations of this quantity termed local wave number are used for source parameter estimation such as body depth and susceptibility, which can be used without any prior information about source geometry. This method was applied on synthetic magnetic data and on the real magnetic data of an area in the Sar-Cheshme region. Using this method, causative body depth varies from 15 to 100 meters in different locations of the studied area, which is in agreement with the existing drilling information and forward modeling.