An investigation for potential extensions of the Karaca Cavern using geophysical methods

Abstract

It is extremely important for regional tourism to determine the possible extensions of Karaca Cavern, one of the most important tourism destinations of the GumuAYhane province in Northeast Turkey. Cavities in karstic areas have been frequently revealed using geophysical surveys. This study tried to ascertain the spatial distribution and extension of the limestone cavern system using these techniques. in pursuit of this goal, ground-penetrating radar (GPR), electrical resistivity tomography and seismic tomography methods were performed close to the Karaca Cavern. Appropriate sites for geophysical measurement were selected within the investigation area. the GPR measurements were collected with 100 MHz centre frequency unshielded antennas on 15 profiles over the investigation area of 5,000 m(2). Furthermore, both electrical resistivity and seismic tomography data were acquired along with one profile on the site. All data sets were processed and interpreted to visualize the cave as well as the shallow subsurface structure of the site. As a result, it was found that a variety of hyperbolic reflections of different depths and sizes on the radargrams as well as low velocity and high resistivity areas with respect host rock observed in the seismic and resistivity tomography sections may indicate possible extensions of the Karaca Cavern. It has been suggested that locations of anomalies pinpointed using these methods could be opened at the sites. If these places are drilled, the cavern may be enlarged and its importance may increase in terms of tourism.