Application of Pareto Joint Inversion in MT and Gravity Data Interpretation - Example from North Poland

In this paper results of joint inversion of magnetotelluric and gravity field data were presented and contrasted with results from classic 2D MT inversion results. Pareto joint inversion was described. Inversion engine was implemented using Particle Swarm Optimization (PSO) algorithm customized for handle at least two target functions. Gravity/MT profile model of length ca. 13 km was calculated to obtain geological structures. Initial geophysical model for joint inversion calculation was built on base of the information about geology known mainly from boreholes. Each from six layers layer was defined by two parameters, resistivity and density which could be modified during inversion process. Geological model calculated with the use of Pareto inversion shows differences in crystalline basement elevations and some changes in morphology of the top and bottom of Zechstein complexes. It can be concluded that in areas where resolving power of the MT data was greater than this of gravity, MT information was fully preserved but in areas where improvement through introduction of gravity was possible the final model was changed accordingly. Proposed novel solution provides robust geophysical model of high interpretational value.