Crazy that it is possible to take measurements to depths of almost 2.5km (1.5 miles) by flying a helicopter with a giant coil (in a scanning pattern) over an ar

Crazy that it is possible to take measurements to depths of almost 2.5km (1.5 miles) by flying a helicopter with a giant coil (in a scanning pattern) over an area. I wonder if that would allow to map caves with water flowing in them? Here is the paper [0] which can be read in an online reader (but cannot be downloaded) when following the link from Wired (the text on the link is "paper" if you need to search for it). These pages [1][2] seem to be about the data they used and the method (Airborne Electromagnetic Measurement (AEM)) of how it was acquired. I also found an otherwise unrelated page that includes photos how an airborne electromagnetic survey is being done using a helicopter at [3] PS: the title is editorialized because "hydrothermal plumbing system" might be more descriptive than "plumbing". Ars Technica also covered the topic at [4] albeit in shorter length than this article. [0] https://www.nature.com/articles/s41586-021-04379-1 https://www.nature.com/articles/s41586-021-04379-1 [1] https://www.sciencebase.gov/catalog/item/613793ced34e40dd9c0cdae3 https://www.sciencebase.gov/catalog/item/613793ced34e40dd9c0... [2] https://www.sciencebase.gov/catalog/item/5d35fe69e4b01d82ce8a61d1 https://www.sciencebase.gov/catalog/item/5d35fe69e4b01d82ce8... [3] https://water.ca.gov/Programs/Groundwater-Management/Data-and-Tools/AEM https://water.ca.gov/Programs/Groundwater-Management/Data-an... [4] https://arstechnica.com/science/2022/03/imaging-the-plumbing-that-powers-yellowstones-geysers/ https://arstechnica.com/science/2022/03/imaging-the-plumbing...