Fractures models comparison using GIS data around crater lakes in Cameroon volcanic line environment

Abstract

This study assesses the contribution of Landsat 7 ETM + and Landsat 8 OLI images to observe existing fractures and faults of at least 12 km in length around the lakes Nyos, Monoun and Oku whose are three major crater lakes in the Cameroon Volcanic Line (CVL) environment. The results obtained using principal component analysis, directional filters and linear densities show many similarities and some differences. In fact, Landsat 7 ETM+ and Landsat 8 OLI images present 427 lineaments in common, including all known geological linear structures, certain geophysical lineaments and some new fractures. This proves that the area is much more fractured than previously known and that only the environments of lakes Nyos and Monoun are crossed by faults and fractures. Apart from the similarities, the differences observed relate to the lineaments specific to each image, their main direction, their length and the values ​​of the fracturing densities. Also, the results show that the Landsat 7 ETM+ and Landsat 8 OLI images are suitable for the structural research in the CVL environment. But, the Landsat 8 OLI images are more efficient as they have made it possible to reconstitute almost all known geological structures and their lengths.