b'Environmental geophysics Environmental geophysicsof AEM data sets this was a vastlywas less successful in Queensland and different approach to how I had usedVictoria (I evaluate this further below)\x08EM surveys in mineral exploration\x08 In exploration, AEM was a tool to findThis automated approach takes away anomalies and in many cases is stillthe potential for interpreter bias, but used in this mode today\x08 is it right? The jury is still outand we seem to be getting better these days This work led me to the realisationat automating these processes, and that interpretation techniques inincorporating more data\x08environmental geophysics were fundamentally different to techniquesAt many times in my career, I have that I had applied in mineral exploration\x08contemplated the nature of interpretation\x08 For the environmental work we wereWhile lecturing in Environmental Mike Hatchusing multiple whole datasets to getGeophysics I tried to get my students to Associate Editor for to conclusions in one great meltingthink about the nature of interpretation- Environmental geophysicspot, rather than interpreting individualwhich for the most part was met with very michael.hatch@adelaide.edu.au datasets, discarding most of the datablank faces\x08 The students strongly preferred and concentrating on anomalies\x08 Fora narrow, mostly mathematical approach example, an ore-body may be foundto interpretation\x08 Plug the numbers into a Welcome readers to this issuesusing airborne magnetics interpretationprogram and out comes an answer\x08 One column on geophysics applied to theto locate anomalous areas, followed byyear, the Environmental Geophysics Field environment\x08 In this months columnground magnetics and ground electricalDay was at a suburban waste disposal site\x08 I am handing the reins over to Gregsurveys\x08 In each step only a subset of theThe student reports were usually full of Street from Loupe Geophysics\x08 Ivedata is used\x08 Data is lost at each step andmodelling of geophysical responses and been doing some work with Greg latelyinformation gained for a specific goal\x08 short on conclusions about what the data and we got talking about the naturewas really telling us about the site\x08 At these of interpretation\x08 I thought that hisWhen we use geophysics to interpretsites there are always artefacts in the data thoughts were interesting (and he haslandscapes and landscape evolution,that trap the unwary\x08 Most students did not been meaning to write them up for aas we often do in salinity studies, weunderstand that the best approach was to while he says)\x08 Here is Gregs story\x08 use all data in each step to maximiseuse all of the data to try to understand the the information obtained\x08 However, asunderlying system, ignore the traps (great, in mineral exploration it is a one-wayyou found the buried powerline, but how Geophysical interpretation process\x08 You can take a dataset anddoes that help us with understanding the interpret it, but you cannot take anpotential leakage from an abandoned interpretation and return to originalfactory to the northwest?) and see the big data\x08 Some of the information is lost inpicture\x08the interpretation, and the look of your interpretation depends on the aim of theInterpretation has been pondered by work at hand\x08 many throughout history and across many disciplines\x08 In geophysics we make During that time, I was an industryobservations and draw conclusions from supervisor on Ann-Marie Anderson- them\x08 We can also employ basic scientific Mayes PhD thesis (Anderson-Mayes,principles and bring some geological 1999), which focused on how tounderstanding into the mix which dictate maximise information from multivariatethe causes and effects\x08 Then there is the datasets\x08 This led to many discussionsunderlying mathematics that can be about What is interpretation?\x08 Ann- used to predict and explain how events Greg StreetMarie stressed that the conventionalhappen\x08 Many prominent philosophers gstreet@iinet.net.au approach where we manually, oftenand scientists have deliberated on the separately, interpret each data set, hadunderlying philosophy behind the limitations\x08 As part of her PhD projectprocess we call interpretation\x08 Plato During the late 1980s and into 1990sshe developed a GIS-based analysisstressed experience: as we grow older at World Geoscience Corporation wesystem that ultimately extracted a maphaving made all (?) the mistakes, we carried out many surveys (mostlyof a study area that predicted whichshould become better interpreters\x08 A airborne electromagnetics) tryingareas in the landscape were likely to besimilar approach is inherent I believe to understand the causes of drylandprone to salinity build-up\x08 in the teachings of many Buddhist salinity in the agricultural areas ofphilosophers in seeking enlightenment Australia\x08 As we proceeded with thisAt WGC we used that approach in laterthrough suffering (or making mistakes)\x08work, we realised that it was crucial tostudies as part of the National Airborne interpret multiple data sets together inGeophysics Project (Street et al, 1998,Descartes was a questioning man and order to arrive at some understandingand Pracilio et al, 1998)\x08 Interestingly,opted for a more rationalist (questioning?) of how the landscape was working,this approach worked quite well in theapproach to interpretation\x08 I prefer this and how it had evolved\x08 In the usesouthwest of Western Australia, butCartesian approach as I believe we should 29 PREVIEW APRIL 2021'