This issue's special section was inspired by a series of presentations given in 2023 as part of a forum under the same name at the Bay Area Geophysical Society, the Colorado School of Mines, and two special sessions at IMAGE '23. At the heart of the forum is the existential question: How does applied geophysics remain relevant to the rapidly emergent energy transition and its requirement to secure an unprecedented volume of diverse natural resources while steadfastly minimizing the negative environmental impacts of doing so?

It points to an overwhelming challenge, especially when one reflects on any one of the many individual challenges the energy transition presents. For example, recall the discussion in Jones (2023) noting that the amount of copper required to meet the needs of a modernized “green” power grid is greater than the amount of copper mined in all of human history. Overwhelming, indeed. And yet, there exist opportunities within applied geophysics where innovation in operations, theory, and practice can flourish. The landscape of growth areas for applied geophysics is vast, but a few key themes are emerging:

Strategic minerals. Exploring for and monitoring extraction of a new collection of minerals that power batteries, solar cells, electronics, transportation, and infrastructure is of paramount importance. These minerals are largely underexplored, and mines are sometimes located in politically unstable countries where a supply-chain disruption could have significant economic impact. Cobalt extraction, for example, is concentrated in the Congo, and the manual mining practice is known for poor and exploitive working conditions. Some of the usual techniques apply for mineral exploration, but new ones are emerging as well.

CO2 storage and sequestration. Decarbonizing the air means that we must put the carbon somewhere. Capturing and safely storing this slippery gas is not easy. The main storage sites initially are likely to be power plants that use gas or coal. Areas near cement plants and other industrial sites that produce a lot of CO2 can also be candidates for capture, storage, and sequestration.

Water. The faster we can develop strategies for water resource development, storage, and security, the better off we will be as a planet. No resource is more important, and none is taken for granted more. There are three areas of interest here. The first is coastal aquifers. These supply most of the urban water worldwide, and they are threatened by overdrafting and sea level rise. Flooding caused by sea level rise endangers the water supply for millions, and thus coastal aquifers must be carefully monitored and protected. The second area is aquifer storage and recovery. Developed in water-poor areas, this technique involves injecting fresh water into accessible aquifers during times of abundant water and drawing it down during droughts. The final area, and one that overlaps and segues into the next major theme, is contamination and cleanup. Most major cities and many large industrial facilities have water contamination issues.

Environmental cleanup and monitoring. This of course is well underway, but room remains for improvement — both in technical execution and in the business case for supporting such. Examples of areas requiring extensive work include the following: oil fields and refineries, urban industrial sites, open pit mines (leach piles, tailings piles, etc.), and old mining areas. Of primary concern is the toxicity of these sites as well as their proximity to population centers and ecologically sensitive areas.

Infrastructure. The final area concerns buildings, transportation networks, water delivery systems, and a host of other structures endemic to modern society. These have limited lifetimes, and examples exist where they are used well past those designed life spans. In general, our exploration tools are not well-suited to interrogate buildings or bridges, but the sensors that we have developed are. In addition, we are good at interrogating earth structures such as levees, dams, and the ground under pipelines, roads, and airports, but we have yet to adapt our skills to above-ground man-made structures with the same agility and fidelity. A natural place to look for improvement is in using arrays of permanent sensors and background seismic or electrical noise as our source. Data analysis is more complicated with noise sources, but great strides are being made in sensor technology.

The papers within this special section are a combination of contributed manuscripts and a sampling of material previously covered in the forums described earlier. Look to future issues of TLE as we revisit these themes and include additional papers from the forums and authors close to the topics therein. As for the present issue, the paper by Alumbaugh et al. provides guidance on the level and type of geophysical activity required for CO2 storage and monitoring. Heagy et al. discuss the importance of open-source software and open-science practices in accelerating innovation within geophysics. Liberty and Otheim present a novel solution to the “faster, cheaper, better” problem in data acquisition — often an impediment to geophysical site analysis — in the form of a new low-cost seismic streamer system that can be contained in a relatively small utility cart. Lastly, with an eye toward the pervasiveness of machine learning in the geosciences, Ramdani et al. describe how innovation in this rapidly evolving technology space is being used to merge ground-penetrating radar data with outcrop photogrammetry to yield more readily interpretable “virtual outcrops” as a complement to traditional radargrams.