Ways to listen:
These audios are best accessed via the SoundCloud app (downloadable here). Often these field visits take explorers off the grid and outside cellular service. Soundcloud allows you to download the audio files OR simply enable offline listening (i.e., tracks can be played on your device without a cell or internet connection). Instructions for how to do that are here, and on each audio file location page.
Another Option: TravelStories!!
If you like to listen to other audios about local Earth science, ESE recommends the TravelStories app (downloadable here). It is outstanding! The content and delivery are professional and exactly what we wish our audio files will be in the near future. The company is based in Wyoming. We particularly appreciate their narrations in National and State Parks. We have not connected with them, but if you have found our site, we think you will love theirs.