An Experimental Magnetotelluric Short Sounding During High Sun Spot Activity Cycle in 2013

Abstract

Sun spot activities during the last decades reached their maximum in 2001 and the next peak is predicted in 2014. Year 2013 was a good time to run magnetotelluric (MT) surveys. An experimental MT short sounding was carried out in Waypanas, Ulubelu, Lampung, Indonesia. Phoenix system MTU-5A recorders, high gain MTC-80H magnetic coils, and non-polarized porous pot were used. A three-hour MT sounding was run in the afternoon in March-April 2013. The time series data are transformed into frequency domain to produce MT impedance directly in the field. An MT record with frequencies ranging from 320 down to 0.0013 Hz was successfully obtained. High frequency data set easily collected a large number of excellent cross-powers while the low frequency data set contained a rather limited amount of cross-powers, however most of them were good. With a few bad cross-powers rejection an excellent MT curves produced. The data shows continuous curves of rho-xy, rho-yx, phase-xy phase-yx. The error bars of the curves are negligible or very small. This experiment shows that conducting a cost effective MT survey is possible when MT signals are strong.