INVERSION MODELLING OF SCHLUMBERGER VERTICAL ELECTRICAL SOUNDING DATA USING MODIFIED SYMBIOTIC ORGANISM SEARCH ALGORITHM (MSOS)

• Main Author: Rheza Zamani, Mohammad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/64666
• Institution: Institut Teknologi Bandung

Vertical Electrical Sounding (VES) schlumberger configuration is one of geoelectrical method measurement techniques which is traditionally used to determine 1D models of subsurface structures for earth resources exploration and geotechnical investigations. One way to generate 1D model from VES data is inversion technique. Mathematical equation that correlating VES data and 1D resistivity model is non-linear so if inversion is imposed with a local approach, it has potential to cause convergence to local minimum, therefore global approach algorithm is required. One of algorithms with global approach is modified Symbiotic Organism Search (mSOS), which is a modified algorithm from original algorithm, this algorithm is populationbased algorithm inspired by interactions between organisms in ecosystem. Dissimilar with original algorithm, which has 3 stages of optimization, mSOS algorithm only consists of mutualism and commensalism phase without parasitism phase. In this research, mSOS algorithm was applied to solve VES data inversion problem using synthetic data and field data while still including parasitism phase to increase exploration capacity. Optimum solution is represented by a candidate solution from several models generated randomly from number of populations that capable to survive after passing through three stages. After testing inversion modeling, mSOS algorithm is considered to have good exploration and exploitation capabilities in solution search process. Results of inversion of synthetic data has been proven to be able to retrieve inversion model parameters with match or close to parameters of synthetic data model, while the field data inversion modeling produces a resistivity pattern that has correlation between VES points and borehole data