Waves of the future: Superior inferences from collocated seismic and electromagnetic experiments

Abstract

The advent of high-quality seismological studies of the Earth's continental lithosphere has been paralleled by an explosion in both the quality and quantity of concomitant high-resolution electromagnetic studies. The latter were inspired by technological and intellectual advances during the last decade in the acquisition, processing, modelling and inversion of particularly natural-source magnetotelluric (MT) data. The complementary nature of seismics and MT leads to rejection of hypotheses that may be tenable if only one of them is applied. Equally, inferences supported by both have stronger conviction. Perhaps most useful is when apparent incompatibilities must be reconciled by re-examination of both datasets. This is demonstrated through examples of magnetotelluric and seismic reflection studies undertaken in the last decade in many tectonic environs, from Palaeoproterozoic collision zones to passive margins to active collision zones. Some aspects of MT are explained, particularly the method's sensitivity and resolution of geoelectric directionality and dimensionality. New directions are proposed whereby greater utility of the joint datasets can occur, both at the outset during data acquisition, and in the interpretation phase in modelling and inversion. Also, laboratory measurements of seismic, electrical and rheological properties of the same rock sample will make integrated interpretation more tenable.