Review of USGS OFR 92-516. Special report No. 4

Controversy was inevitable when the DOE selected a seismically and volcanically active terrain as a candidate repository site for the nation`s high-level radioactive waste. At the time, in the late seventies, earth scientists were only dimly aware of the geologic hazards. OFR 92-516 takes us back to a time when it was possible to believe that {open_quotes}the area is essentially tectonically dead{close_quotes}, if one could possibly regard the young volcanic cones flanking Yucca Mountain to the west and south as dying gasps. By the time the Nuclear Waste Policy Act was amended, leaving Yucca Mountain as the only candidate for the repository, site investigations had produced diverse evidence conflicting with the notion of tectonic and hydrologic quiescence. Faults and travertime veins in the faults were found to be youthful, wholesale metasomatic alteration of the ignimbrite rocks of Yucca Mountain was documented, aberrant gradients in subsurface temperature and hydraulic potential were discovered, and rocks were found to fracture under the load of drilling fluids