b'Environmental geophysics Environmental geophysicsMike Hatch Associate Editorfor Environmental geophysics michael.hatch@adelaide.edu.auWelcome readers to this issues column on geophysics applied to the environment. Many thanks again to Niels Christensen from Aarhus UniversityFigure 1.2019 image of AusEM AEM data collected over northern Australia.for his reminiscences over the last few months on a life immersed in geophysics.present on a high precision, 4D surveyAustralia is runningwith the stated goal I am sure that there are many of us whousing shallow resistivity and frequencyof (aspirationally) covering the entire recognised ourselves in at least parts ofdomain electromagnetics to measure/ country with AEM. Im sure that Yusen Ley-what he has written. estimate/visualise solute transport inCooper will have better images than what the top few metres of the subsurface.I just grabbed off the web, but even this AEGC 2023 picks Solute transport is a notoriously difficultincomplete view of Australia under cover process to image, so it will be interestingis compelling (see Figure 1).For this issue, as it is the AEGC 2023to see what they do to improve results.conference issue, I thought that I wouldI completely agree with Robert Hearst have a look through the conferenceI have a personal interest (not justfrom Southern Geoscience Consultants abstracts and pick a few that I thoughtas a shallow geophysicist) in dataabout the benefits of going deeper were interesting. It has been such aleakage between techniques. It iswith geophysical surveys than just long time since I have attended anywell known in exploration that the datathe expected extraction depth limit conference, other than virtually, so I amcollected using good old-fashioned,of the target (or the equivalent for really excited to head over to Brisbanegalvanically-based, resistivity/inducedenvironmental surveys). There is always to see what is going on. As always whenpolarisation (IP) surveys are affecteduseful and sometimes actually important I do these reviews, I recommend a fewby electromagnetic (EM) induction,information in that deeper part of the presentations that are of interest to meespecially the IP part of the data set,data set that is most likely unanticipated,most will be related to environmentaland must be accounted for. Andreaand may provide information about the geophysics, but not necessarily. So, for theViezzoli, from Aarhus Geophysics, hasmineralising system, as well as possibly upcoming conference I introduce eightbeen going the other way for years,locating deeper mineralisation.presentations that at first glance I foundrecognising that EM data sets are often affected by IP. And, therefore,As many of you who read this column interesting. I am very very sure that onwill realise, Loupe EM is presently my second glance I will find a lot more to gettargets may have been missed through incorrect inversion and interpretation. favourite EM technique. Greg Street and excited about. But here is what my firstAndrew Duncan are presenting the latest glance suggestsin no particular order. Darren Burrows from Xcaliburand greatest in Loupe EM.First off, I noticed a couple ofMultiphysics, discusses the need for, but then also discusses the difficulties in using,And finally, Tim Dean from Anglo presentations by Chris Wijns and othersAmerican, wins my award for best from First Quantum Minerals on the needairborne EM surveys (AEM) to help South American iron ore producer Vale bothpresentation title. He has two that are for higher resolution information in theoutstanding but Nuclear weapons as a laterite resource space, and their effortsto characterise tailing storage facilities (some with incomplete constructionseismic source. is my favourite. Its true, to use various geophysical techniquesnothing beats a good atomic explosion, in this particularly shallow workrecords), as well as to explore for iron ore. The difficulties come with tough ground- and while you (the reader) are right, he is environment, where nearly no contactscontemplating extra big seismic sources, are flat, and the contacts matter. access (HSE issues), topographically complex settings and large field areas. much of this one looks at work from Lee Slater from Rutgers University inthe 60s and 70s where researchers were the US (along with a number of otherOn a larger scale, I am a huge fanimproving hydraulic permeability using mostly American researchers) willof the AusEM project that Geoscience atomic bombs. Fraccing hell!43 PREVIEW FEBRUARY 2023'