Keanakākoʻi Tephra deposit in Kīlauea south caldera wall

Keanakākoʻi Tephra from unit D in Kīlauea south caldera wall; the lower portion of the tephra deposit has been smoothed with a scraper tool, making the surface look different from the portion above. a) finely laminated ash layers as well as a fine ash layer and a coarser layer with pumice grains, b) microscope photo of a dense, glassy ash grain from the fine lamination layers, c) microscope photo of a small pumice grain from the coarser layer, and d) well-preserved example of a fine ash layer with accretionary lapilli. USGS photos by J. Schmith.