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Identifying the boundaries of source bodies is one of the most important aims in interpreting gravity and magnetic data. For this purpose, many amplitude and phase-based methods have been utilized. Amplitude-based filters cannot balance the anomalies caused by deep and shallow sources. Although phase-based filters do not have such a problem, the edges detected by using these filters may be incompatible with actual edges. To overcome these problems, many maximum detection algorithms have been developed, e.g., the curvature analysis algorithm, the Blakely and Simpson's algorithm, and its modified version. In this study, the edge mapping performances of these algorithms are discussed and a new approach is introduced. The validity of the introduced algorithm is illustrated with two synthetic gravity data caused by vertical-prism sources. The results show that the proposed technique detects the source edges more clearly. In addition, the proposed technique has been applied to the gravity data of the Tuan Giao area in Vietnam and the magnetic data of the Narmada-Son Lineament in India, and it has been observed that the obtained results are consistent with the known geological structures in these study areas.

Determining lateral boundaries of the potential field source is a common feature in interpreting magnetic and gravity data. There are many different phase based filters to determine the boundaries of the source. The purpose of this study is to compare the performance of phase-based filters such as tilt derivative, theta map, normalized horizontal derivative, tilt derivative of the horizontal derivative, tilt derivative of the total gradient, improved theta and horizontal gradient of a modified version of tilt derivative. In order to obtain optimum results, these filters were tested on synthetic magnetic and gravity anomaly data and also aeromagnetic anomaly from the Seattle Uplift (SU), Washington, United States of America. The results show that the tilt derivative of the horizontal derivative method revealed better detection of the source edges compared to the results by the other filters. These results demonstrate that the tilt derivative of the horizontal derivative method is a useful tool for the qualitative interpretation of magnetic and gravity data.

The Isparta Angle (IA) is formed as a morphotectonic pattern and located in the north of the Antalya Gulf. It is a seismotectonically very active zone as in the Eastern Mediterranean Region. The shape of Isparta Angle is a wedge-like with flanks oriented NE–SW in the west and NW–SE in the east rather than compressional E–W-oriented structures preceding its present shape. It results from the clockwise and anti-clockwise rotation of the Anatolian Plate from the Early Paleocene to the Early Pliocene. In this study, we determined the neotectonic pattern of the IA by using arrival time data of P and S waves. We assessed the 3-D tomographic images from the data of local earthquakes. The tomographic results verified the major tectonic structures and discontinuities in the studied area. The results have revealed the young structural heterogeneities related to the seismotectonic zones. While the higher Vp and Vs distributions are determined in the shallow levels of the earth, low-velocity perturbations are extensively distributed at deeper levels of the crust. The seismotectonic activity, seen along heterogeneous zones, denotes the high-velocity perturbation and is related to the pre-existing faults. The results of checkerboard tests showed that the anomalies are reliable down to approximately 40 km depth. From the middle to the lower crust, the low-velocity zones are related to the geophysical and geological evidence in the Fethiye–Burdur Fault Zone (FBFZ) and the existence of mantle material is consistent with the partial melt in the upper mantle. Furthermore, the present study revealed the new active zones from 3-D tomographic results: the NW-trending Yalvac, NE-trending Gelendost, and approximately N–S-trending Egirdir–Kovada grabens existing in the northern core of IA.