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Gravity data, which was obtained from southern part toward the north of Yogyakarta, was already used to identify the existence and depth of Kali Opak Fault and others. By applying the Multi Scale Second Vertical Derivative (MS-SVD) method, the location of fault and dip can be identified. The gravity anomaly in the form of Complete Bouguer Anomaly (CBA) is carried out upward continuation (UC) several times for many different of heights h. The SVD is performed on each high of  continuation to identify the location of faults, i.e. when the SVD value is zero. Since the UC correlates to the depth of body anomaly, the dip of fault is obtained. So, the strike, dip size, location, type, and depth of faults are described. There are two main faults identified around the Kali Opak with normal fault types. One of them is strongly suspected as the existence of Kali Opak Fault with a strike and dip direction of N34⁰E/105⁰ in the North side and N55.6⁰E/115⁰ in the South side, while the other fault is on the northwest side of the Opak River with a strike and dip direction of N43⁰E/65⁰.

Multi Scale Second Vertival Derivative, Gravity Data, Opak River Fault, Yogyakarta