Seismically-Induced Lateral Spreads Analyzed for Liquefaction and Cyclic Failure Mechanisms, Dixie Valley, NV
Paleo-lateral spreads, dated 2,000 to 2,500 years ago, have been identified by previous researchers in Dixie Valley, Nevada, a seismically active area of central Nevada which is bound to the west by the Stillwater Range and to the east by the Clan-Alpine Range. The study area is located between the Stillwater Range faults and the basin playa, and is composed of alluvial fan material washed down from the westward bounding Stillwater Range and of beach gravel, sands and fines from the eastward bounding pluvial Lake Dixie. Analysis of subsurface samples revealed that among the fines is black low-strength clays identified by XRD as primarily smectites. The clay quickly forms a beige oxidized rind and was identified by total organic carbon analyses to contain less than 1% organic material. While preliminary field work indicated the presence of sand boils and fissures consistent with seismically-induced lateral spreading due to liquefaction, the low-strength clay presents the possibility of seismically-induced lateral spreading due to cyclic failure. On-going lab analyses and modeling will identify the units most likely to fail during earthquake loading, and by which mechanism.
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- 7221 Paleoseismology (8036)