Geology of the Waste Treatment Plant Seismic Boreholes. Rev. 1.

Barnett, D. B. ; Frecht, K. R. ; Reidel, S. P. ; Bjornstad, B. N. ; Lanigan, D. C.

Technical Information Center Oak Ridge Tennessee

关键词: Boreholes;    Radioactive waste storage;    Waste treatment plants;    Borehole drilling;    Sedimentary interbeds;   

RP-ID  :  DE2007912724

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

In 2006, the U.S. Department of Energy initiated the Seismic Boreholes Project (SBP) to emplace boreholes at the Waste Treatment Plant (WTP) site in order to obtain direct shear wave velocity (Vs) measurements and other physical property measurements in Columbia River basalt and interbedded sediments of the Ellensburg Formation. The goal was to reduce the uncertainty in the response spectra and seismic design basis, and potentially recover design margin for the WTP. The characterization effort within the deep boreholes included (1) downhole measurements of the velocity properties of the suprabasalt, basalt, and sedimentary interbed sequences, (2) downhole measurements of the density of the subsurface basalt and sediments, and (3) geologic studies to confirm the geometry of the contact between the various basalt and interbedded sediments through examination of retrieved core from the core hole and data collected through geophysical logging of each borehole. This report describes the results of the geologic studies from three mud-rotary boreholes and one cored borehole at the WTP. All four boreholes penetrated the entire Saddle Mountains Basalt and the upper part of the Wanapum Basalt where thick sedimentary interbeds occur between the lava flows. The basalt flows penetrated in Saddle Mountains Basalt included the Umatilla Member, Esquatzel Member, Pomona Member, and the Elephant Mountain Member. The underlying Priest Rapids Member of the Wanapum Basalt also was penetrated. The Ellensburg Formation sediments consist of the Mabton Interbed, the Cold Creek Interbed, the Selah Interbed, and the Rattlesnake Ridge Interbed; the Byron Interbed occurs between two flows of the Priest Rapids Member. The Mabton Interbed marks the contact between the Wanapum and Saddle Mountains Basalts. The thicknesses of the basalts and interbedded sediments were within expected limits. However, a small reverse fault was found in the Pomona Member flow top. This fault has three periods of movement and less than 15 ft of repeated section. Most of the movement on the fault appears to have occurred before the youngest lava flow, the 10.5-million-year-old Elephant Mountain Member, was emplaced above the Pomona Member.