The aim of this campaign is the determination of the electric conductivity structure of a highly active volcano based on measurements at Merapi. The results will provide basic information for experiments on this volcano in the framework of the DFG-project MERAPI (Mechanism Evaluation, Risk Assessment, Prediction Improvement). The spatial distribution of a surprisingly good conductor (1 Ohmm) detected during a preliminary campaign in 1997 in a depth range 1 - 3 km should be resolved. For this purpose we use 2 broadband magnetotelluric instruments (S.P.A.M.) and 5 PDAS-Dataloggers to cover the relevant frequency range 0.001 - 10 Hz.