Geophysical Journal | 2009 volume 31 4

Comprehensive interpretation of the data of electromagnetic soundings with natural and controlled source in seismically active areas (on an example of Gornyi Altay)

© N.N. Nevedrova, E.V. Pospeeva

The paper presents some results obtained by the set of electromagnetic methods: sounding by electromagnetic field formation (SEF), vertical electrical sounding (VES), and magneto-telluric sounding (MTS). The measurements were performed in the epicenter part of Chuya earthquake of 2003, which occurred in the nearest mountain frame of the Chuya tectonic depression in Gornyi Altai. The ways of joint interpretation of field data acquired by soundings with both controllable and natural sources have been demonstrated. As a result, geo-electrical parameters of rocks have been determined from two observation profiles within the wide depth interval. Each method used has its own advantages: data of VES and SEF soundings reflect in more detail the upper geoelectrical section part to 1,5-2 km in depth, whereas MTS allows to obtain information about the deep lithosphere structure. From the MTS data information about the uplift of the top of a conductive crust layer within the bonds of the area under investigation has been obtained. Besides, applying the joint approach to data processing increases a reliability of the results obtained.

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