FIGURE 2.13 . Topography of the broad zone of plate boundary deformation
within the western United States and adjacent
portions of Canada and Mexico, at low, medium, and high horizontal
resolutions (300, 80, and 20 km). The height scale ranges
from 400 m (violet) to 2400 m (red). At low resolution (i.e., topography
smoothed to eliminate features with horizontal length
scales smaller than 300 km), only the most general topographic features of
this plate boundary zone can be distinguished. At
medium resolution, large features such as the Sierra Nevada begin to emerge.
At high resolution, small-scale mountain blocks and
valleys that are key indicators of crustal extension of the Basin and
Range Province appear. The low resolution in this figure
is
comparable to or better than current seismic tomography images of most of
the upper mantle. Obtaining seismic images at the
high resolution is one of the goals of the EarthScope initiative. SOURCE:
G. Humphries, University of Oregon.
SCIENCE OPPORTUNITIES
70
About this PDF file: This new digital representation of the
original work has been recomposed from XML files created
from the original
paper book, not from the original
typesetting files. Page breaks are true to the original; line lengths,
word breaks, heading styles, and other typesetting-specific
formatting, however, cannot be retained,
and some typographic errors may have been accidentally
inserted. Please use the print version of this publication
as the authoritative
version for attribution.