For most injection wells regulations only address the well structure and site because it is assumed that the natural geological layering makes vertical migration impossible. (dotearth.blogs.nytimes.com)
Sep 2014 There are two basic approaches relative geologic age dating, and absolute geological layers of sedimentary rock, exposed along the highway, Salt River Canyon, Arizona No bones about it, fossils are important age markers. (petesgrillandpizza.com)
To further refine the probability estimates, they took into account past (prior to recorded history) tsunamis — evidence of which is preserved in geological layers in coastal sediments, volcanic tephras, and archeological sites. (sciencedaily.com)