NEAR SURFACE APPLICATION OF TENSORIAL GRAVITY AND TOTAL MAGNETIC FIELD INTENSITY- MODELLING AND CASE STUDIES

Abstract

This study describes the modelling of gravity and magnetic responses of cavities and sinkholes by using prisms. A tunnel in the shape of a long rectangular prism is considered and the gravity and gravity gradient responses of said body is computed and studied for different depths. A sinkhole is modelled using five rectangular prisms and the response is computed by the summation of the individual responses of the five bodies and in this way the gravity response, gravity gradient response and the magnetic response of the cavity is computed. Matlab code has been used to generate responses of the individual prisms. A case study has also been considered to model the response of a sinkhole along the dead sea coast. Such preliminary gravity modelling study can be an important tool in planning high-precision microgravity surveys. The microgravity maps can show the presence of cavities beneath areas where sinkholes exist, which can predict further sinkhole development in the region. In addition, magnetic method can also detect shallow voids or caves. The efficiency of the method will depend on the use of an integrated geophysical approach.