Special issue “Studies on electromagnetic induction in the earth: recent advances and future directions”

© The Author(s) 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creat iveco mmons .org/licen ses/by/4.0/. The research community that studies electromagnetic (EM) induction in the Earth and planets continues to grow. The breadth of EM research has expanded well beyond the traditional focus on magnetotellurics (MT) to include airborne, land, and marine controlled-source EM. Advancements in the processing, modeling, inversion and interpretation of EM data have accompanied this growth and led to an increased visibility of EM research within the Earth science community. The biennial workshops on Electromagnetic Induction in the Earth, first held in 1972, continues to be the premier event for the vibrant international community of EM researchers. The 24th workshop on Electromagnetic Induction in the Earth was held in Helsingør, Denmark, from August 13–20, 2018. More than 330 presentations were given spanning a range of topics including (1) instrumentation, sources and data processing; (2) EM theory, modeling and inversion; (3) exploration, monitoring and hazards; (4) tectonics, magmatism and geodynamics; (5) marine EM; (6) rock/mineral resistivity and anisotropy; (7) global and planetary studies and (8) EM induction education and outreach. This special issue presents a compilation of 10 papers, described below, that highlight recent advances and future directions within the EM research community. Investigations of crustal and lithospheric architecture continue to be a mainstay of MT studies. Comeau et al. (2020) present a study of the tectonic terranes of Mongolia based upon a 350-km-long MT profile. Their resistivity model images zones of elevated upper-crustal conductivity coincident with surface faulting and seismicity; they interpret these zones to mark suture zones within the Central Asian Orogenic Belt. The authors further image a distinct zone of lower-crustal conductivity in part of the model and suggest this conductor may be related to an exotic terrane speculated from geochemical data to exist in the same region. Finally, a step in lithospheric thickness is interpreted beneath Southern Mongolia from the model. The emergence of national-scale MT initiatives over the last two decades has led to an explosion in the number of three-dimensional (3D), tectonic-scale resistivity models presented and published. Thiel et al. (2020) present one such model, describing MT modeling of the Australian Musgrave province based upon data collected as part of the Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP).