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Title: Astor Pass Seismic Surveys Preliminary Report

Abstract

In collaboration with the Pyramid Lake Paiute Tribe (PLPT), the University of Nevada, Reno (UNR) and Optim re-processed, or collected and processed, over 24 miles of 2d seismic-reflection data near the northwest corner of Pyramid Lake, Nevada. The network of 2d land surveys achieved a near-3d density at the Astor Pass geothermal prospect that the PLPT drilled during Nov. 2010 to Feb. 2011. The Bureau of Indian Affairs funded additional seismic work around the Lake, and an extensive, detailed single-channel marine survey producing more than 300 miles of section, imaging more than 120 ft below the Lake bottom. Optim’s land data collection utilized multiple heavy vibrators and recorded over 200 channels live, providing a state-of-the-art reflection-refraction data set. After advanced seismic analysis including first-arrival velocity optimization and prestack depth migration, the 2d sections show clear fault-plane reflections, in some areas as deep as 4000 ft, tying to distinct terminations of the mostly volcanic stratigraphy. Some lines achieved velocity control to 3000 ft depth; all lines show reflections and terminations to 5000 ft depth. Three separate sets of normal faults appear in an initial interpretation of fault reflections and stratigraphic terminations, after loading the data into the OpendTect 3d seismic visualizationmore » system. Each preliminary fault set includes a continuous trace more than 3000 ft long, and a swarm of short fault strands. The three preliminary normal-fault sets strike northerly with westward dip, northwesterly with northeast dip, and easterly with north dip. An intersection of all three fault systems documented in the seismic sections at the end of Phase I helped to locate the APS-2 and APS-3 slimholes. The seismic sections do not show the faults connected to the Astor Pass tufa spire, suggesting that we have imaged mostly Tertiary-aged faults. We hypothesize that the Recent, active faults that produced the tufa through hotspring activity do not have enough offset to produce seismic terminations. We are conducting further high-resolution seismic studies (to 200 ft depths) at the tufa spire to test this hypothesis. Additional work in progress includes a collaborative, iterative joint interpretation of geologic mapping and the seismic sections for fault locations, building the geologic model; and 3d velocity modeling and imaging to locate additional faultplane images appearing between the 2d lines. Overall, the seismic exploration program cost less than $0.5M from all funders. It defines in detail the geologic structure of much of the north margin of Pyramid Lake.« less

Authors:
 [1];  [2]; ; ; ; ;
  1. UNR
  2. Optim
Publication Date:
Research Org.:
Regents of the Nevada System of Higher Education
Sponsoring Org.:
USDOE
Contributing Org.:
Optim
OSTI Identifier:
1111715
Report Number(s):
DOE-Pyramid-2842-jl16
DOE Contract Number:  
EE0002842
Resource Type:
Other
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; 01 COAL, LIGNITE, AND PEAT

Citation Formats

Louie, John, Pullammanappallil, Satish, Faulds, James, Eisses, Amy, Kell, Annie, Frary, Roxanna, and Kent, Graham. Astor Pass Seismic Surveys Preliminary Report. United States: N. p., 2011. Web.
Louie, John, Pullammanappallil, Satish, Faulds, James, Eisses, Amy, Kell, Annie, Frary, Roxanna, & Kent, Graham. Astor Pass Seismic Surveys Preliminary Report. United States.
Louie, John, Pullammanappallil, Satish, Faulds, James, Eisses, Amy, Kell, Annie, Frary, Roxanna, and Kent, Graham. 2011. "Astor Pass Seismic Surveys Preliminary Report". United States. https://www.osti.gov/servlets/purl/1111715.
@article{osti_1111715,
title = {Astor Pass Seismic Surveys Preliminary Report},
author = {Louie, John and Pullammanappallil, Satish and Faulds, James and Eisses, Amy and Kell, Annie and Frary, Roxanna and Kent, Graham},
abstractNote = {In collaboration with the Pyramid Lake Paiute Tribe (PLPT), the University of Nevada, Reno (UNR) and Optim re-processed, or collected and processed, over 24 miles of 2d seismic-reflection data near the northwest corner of Pyramid Lake, Nevada. The network of 2d land surveys achieved a near-3d density at the Astor Pass geothermal prospect that the PLPT drilled during Nov. 2010 to Feb. 2011. The Bureau of Indian Affairs funded additional seismic work around the Lake, and an extensive, detailed single-channel marine survey producing more than 300 miles of section, imaging more than 120 ft below the Lake bottom. Optim’s land data collection utilized multiple heavy vibrators and recorded over 200 channels live, providing a state-of-the-art reflection-refraction data set. After advanced seismic analysis including first-arrival velocity optimization and prestack depth migration, the 2d sections show clear fault-plane reflections, in some areas as deep as 4000 ft, tying to distinct terminations of the mostly volcanic stratigraphy. Some lines achieved velocity control to 3000 ft depth; all lines show reflections and terminations to 5000 ft depth. Three separate sets of normal faults appear in an initial interpretation of fault reflections and stratigraphic terminations, after loading the data into the OpendTect 3d seismic visualization system. Each preliminary fault set includes a continuous trace more than 3000 ft long, and a swarm of short fault strands. The three preliminary normal-fault sets strike northerly with westward dip, northwesterly with northeast dip, and easterly with north dip. An intersection of all three fault systems documented in the seismic sections at the end of Phase I helped to locate the APS-2 and APS-3 slimholes. The seismic sections do not show the faults connected to the Astor Pass tufa spire, suggesting that we have imaged mostly Tertiary-aged faults. We hypothesize that the Recent, active faults that produced the tufa through hotspring activity do not have enough offset to produce seismic terminations. We are conducting further high-resolution seismic studies (to 200 ft depths) at the tufa spire to test this hypothesis. Additional work in progress includes a collaborative, iterative joint interpretation of geologic mapping and the seismic sections for fault locations, building the geologic model; and 3d velocity modeling and imaging to locate additional faultplane images appearing between the 2d lines. Overall, the seismic exploration program cost less than $0.5M from all funders. It defines in detail the geologic structure of much of the north margin of Pyramid Lake.},
doi = {},
url = {https://www.osti.gov/biblio/1111715}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Aug 05 00:00:00 EDT 2011},
month = {Fri Aug 05 00:00:00 EDT 2011}
}