Imaging of subsurface lineaments in the southwestern part of the Thrace Basin from gravity data

D Aydogan,S Yuksel,O Tarhan Bal,A Pinar,A Elmas

doi:10.5047/eps.2012.08.014

Abstract

Linear anomalies, as an indicator of the structural features of some geological bodies, are very important for the interpretation of gravity and magnetic data. In this study, an image processing technique known as the Hough transform (HT) algorithm is described for determining invisible boundaries and extensions in gravity anomaly maps. The Hough function implements the Hough transform used to extract straight lines or circles within two-dimensional potential field images. It is defined as image and Hough space. In the Hough domain, this function transforms each nonzero point in the parameter domain to a sinusoid. In the image space, each point in the Hough space is transformed to a straight line or circle. Lineaments are depicted from these straight lines which are transformed in the image domain. An application of the Hough transform to the Bouguer anomaly map of the southwestern part of the Thrace Basin, NW Turkey, shows the effectiveness of the proposed approach. Based on geological data and gravity data, the structural features in the southwestern part of the Thrace Basin are investigated by applying the proposed approach and the Blakely and Simpson method. Lineaments identified by these approaches are generally in good accordance with previously-mapped surface faults.

Highlights

The Thrace Basin in northwestern Turkey (Fig. 1(a)), is a triangular-shaped Cenozoic depression (Doust and Arıkan, 1974; Keskin, 1974; Turgut et al, 1983) whose sedimentary fill in the centre of the basin reaches up to 9000 meters in thickness (Kopp et al, 1969; Turgut et al, 1991; Siyako and Huvaz, 2007)
The southwestern part of the Thrace Basin in Turkey is selected as a study area to demonstrate the capabilities of the Hough transform algorithm for lineaments extraction
The Hough transform algorithm is a powerful tool against noise, since the possibility of noise data points making a contribution to a peak in the parameter space is quite low

Summary

Introduction

The Thrace Basin in northwestern Turkey (Fig. 1(a)), is a triangular-shaped Cenozoic depression (Doust and Arıkan, 1974; Keskin, 1974; Turgut et al, 1983) whose sedimentary fill in the centre of the basin reaches up to 9000 meters in thickness (Kopp et al, 1969; Turgut et al, 1991; Siyako and Huvaz, 2007). In the southwestern part of the Thrace Basin, the first detailed geological map (Fig. 1(b)), including structural elements, was produced by Elmas et al (2008). Geophysicists usually deal with lineaments as an indicator of a fault, boundary or any tectonic feature beneath the surface for the interpretation of gravity and magnetic anomaly maps.

Results

Conclusion