Edge Detection and Depth Estimation Using a Tilt Angle Map from Gravity Gradient Data of the Kozaklı-Central Anatolia Region, Turkey

Abstract

In this paper the application of an edge detection technique to gravity data is described. The technique is based on the tilt angle map (TAM) obtained from the first vertical gradient of a gravity anomaly. The zero contours of the tilt angle correspond to the boundaries of geologic discontinuities and are used to detect the linear features in gravity data. I also present that the distance between zero and AEp=4 pairs obtained from the TAM corresponds to the depth to the top of the vertical contact model. Alternatively, the half distance between Àp=4 and þp=4 radians is equal to the depth to the same model. I illustrate the applicability of the present method by gravity data due to buried vertical prisms, imaging the positions of the edges of the prisms. The results obtained from the theoretical data, with and without random noise, have been discussed. The analysis of the TAM has been demonstrated on a field example from the Kozaklı-Central Anatolian region, Turkey, and the location and depth of the edges of the structural uplifts of the Kozaklı graben are imaged. The results indicated that depth values from these sources have ranged between 0.2 and 0.6 km. I have also compared the Euler deconvolution technique with the TAM images obtained from the first vertical gradient of residual gravity anomaly. Both techniques have agreed closely in detecting the horizontal location and depth of the uplift edges in the subsurface with good precision.

Interpretation of gravity anomalies to delineate some structural features of Biga and Gelibolu peninsulas, and their surroundings (north-west Turkey)

“…Directional derivative-based techniques commonly use vertical or horizontal gradients (derivatives) of degree first or second, analytic signal (AS) amplitudes or their various combinations in order to improve the edges, and also to outline the possible boundaries of the gravity and pseudogravity sources (e.g. Balkaya, Göktürkler, Erhan, & Levent, Ekinci, 2012;Blakely & Simpson, 1986;Debeglia & Corpel, 1997;Oruç, 2011Oruç, , 2014Roest, Verhoef, & Pilkington, 1992). Inversion techniques are frequently used to estimate the model parameters whose responses are similar to the measured data, but the wellknown under-determined and non-uniqueness nature of the potential field data makes the processing and interpretation difficult.…”

3-D Potential Field Inversion of Camp Clubhouse Crossroads Mafic Intrusive Pluton, Coastal Plain, South Carolina

“…The math calculations are based on Fast Fourier Transformation (FFT). The technique is based on the tilt angle of the first vertical gradient of gravity anomaly (Oruc, 2011). The technique was first proposed by Miller and Singh (2003), and developed by Verduzco et al (2004) in order to be used for gridded data, and suggested to be used with the total horizontal derivative of the tilt angle as an edge detector (Oruc, 2011).…”

“…where is the magnetic or gravity field and / , / , and / are the first derivative in x, y, and, z directions. The tilt amplitudes range between − /2 and + /2 which corresponds to a wide dynamic range of amplitudes for sources at different depths (Oruc, 2011). Verduzco et al (2004) stated that the angle is also employed as an automatic-gain-control-filter in order to equalize the results from weak and strong potential field anomalies.…”

“…If the tilt angle technique is applied to the first vertical gradient Fast Fourier Transform (FFT) technique calculates the vertical gradient of gravity data. Also, it calculates the vertical derivative of which is necessary for the calculation of tilt angle (Oruc, 2011). The Gravity Fourier equation is…”

Caracterización de lineamientos estructurales y sus implicaciones hidrogeológicas en la cuenca de Villa Hidalgo (San Luis Potosí) integrando métodos geofísicos potenciales

“…Por lo tanto la DE confirma los resultados de la AI, bajo el supuesto de que los bordes de las fuentes anómalas son causadas por contactos verticales. Esta correlación es una manera de confirmar la ubicación horizontal y la profundidad de bordes que reflejan diferentes atributos de características lineales, tales como fallas, contactos, bordes de cuencas y levantamientos (Oruç, 2011). La configuración de la gravimetría terrestre (Figura 6B) muestra que el sistema dominante es el NW-SE, así como el N-S y en menor medida el NE-SW, evidenciando que en la parte central del mapa, y en la porción oriental el valor de cero del AI junto con la Deconvolución de Euler tiene una coincidencia adecuada, asociadas a posibles fallas.…”