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Title: An image of the Columbia Plateau from inversion of high-resolution seismic data

Abstract

The authors use a method of traveltime inversion of high-resolution seismic data to provide the first reliable images of internal details of the Columbia River Basalt Group (CRBG), the subsurface basalt/sediment interface, and the deeper sediment/basement interface. Velocity structure within the basalts, delineated on the order of 1 km horizontally and 0.2 km vertically, is constrained to within [plus minus]0.1 km/s for most of the seismic profile. Over 5,000 observed traveltimes fit their model with an rms error of 0.018 s. The maximum depth of penetration of the basalt diving waves (truncated by underlying low-velocity sediments) provides a reliable estimate of the depth to the base of the basalt, which agrees with well-log measurements to within 0.05 km (165 ft). The authors use image blurring, calculated from the resolution matrix, to estimate the aspect ratio of images velocity anomaly widths to true widths for velocity features within the basalt. From their calculations of image blurring, they interpret low velocity zones (LVZ) within the basalts at Boylston Mountain and the Whiskey Dick anticline to have widths of 4.5 and 3 km, respectively, within the upper 1.5 km of the model. At greater depth, the widths of these imaged LVZs thin tomore » approximately 2 km or less. They interpret these linear, subparallel, low-velocity zones imaged adjacent to anticlines of the Yakima Fold Belt to be brecciated fault zones. These fault zones dip to the south at angles between 15 to 45 degrees.« less

Authors:
;  [1];  [2]
  1. Geological Survey, Menlo Park, CA (United States)
  2. Amoco Production Co., Tulsa, OK (United States)
Publication Date:
OSTI Identifier:
7059981
Resource Type:
Journal Article
Journal Name:
Geophysics; (United States)
Additional Journal Information:
Journal Volume: 59:8; Journal ID: ISSN 0016-8033
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; GEOLOGIC DEPOSITS; SEISMIC SURVEYS; OREGON; DATA ANALYSIS; IMAGE PROCESSING; WASHINGTON; BASALT; DEVELOPED COUNTRIES; GEOPHYSICAL SURVEYS; IGNEOUS ROCKS; NORTH AMERICA; PROCESSING; ROCKS; SURVEYS; USA; VOLCANIC ROCKS; 580000* - Geosciences

Citation Formats

Lutter, W J, Catchings, R D, and Jarchow, C M. An image of the Columbia Plateau from inversion of high-resolution seismic data. United States: N. p., 1994. Web. doi:10.1190/1.1443685.
Lutter, W J, Catchings, R D, & Jarchow, C M. An image of the Columbia Plateau from inversion of high-resolution seismic data. United States. https://doi.org/10.1190/1.1443685
Lutter, W J, Catchings, R D, and Jarchow, C M. 1994. "An image of the Columbia Plateau from inversion of high-resolution seismic data". United States. https://doi.org/10.1190/1.1443685.
@article{osti_7059981,
title = {An image of the Columbia Plateau from inversion of high-resolution seismic data},
author = {Lutter, W J and Catchings, R D and Jarchow, C M},
abstractNote = {The authors use a method of traveltime inversion of high-resolution seismic data to provide the first reliable images of internal details of the Columbia River Basalt Group (CRBG), the subsurface basalt/sediment interface, and the deeper sediment/basement interface. Velocity structure within the basalts, delineated on the order of 1 km horizontally and 0.2 km vertically, is constrained to within [plus minus]0.1 km/s for most of the seismic profile. Over 5,000 observed traveltimes fit their model with an rms error of 0.018 s. The maximum depth of penetration of the basalt diving waves (truncated by underlying low-velocity sediments) provides a reliable estimate of the depth to the base of the basalt, which agrees with well-log measurements to within 0.05 km (165 ft). The authors use image blurring, calculated from the resolution matrix, to estimate the aspect ratio of images velocity anomaly widths to true widths for velocity features within the basalt. From their calculations of image blurring, they interpret low velocity zones (LVZ) within the basalts at Boylston Mountain and the Whiskey Dick anticline to have widths of 4.5 and 3 km, respectively, within the upper 1.5 km of the model. At greater depth, the widths of these imaged LVZs thin to approximately 2 km or less. They interpret these linear, subparallel, low-velocity zones imaged adjacent to anticlines of the Yakima Fold Belt to be brecciated fault zones. These fault zones dip to the south at angles between 15 to 45 degrees.},
doi = {10.1190/1.1443685},
url = {https://www.osti.gov/biblio/7059981}, journal = {Geophysics; (United States)},
issn = {0016-8033},
number = ,
volume = 59:8,
place = {United States},
year = {Mon Aug 01 00:00:00 EDT 1994},
month = {Mon Aug 01 00:00:00 EDT 1994}
}