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Subsurface Weathering Revealed in Hillslope‐Integrated Porosity Distributions
Author(s) -
Callahan Russell P.,
Riebe Clifford S.,
Pasquet Sylvain,
Ferrier Ken L.,
Grana Dario,
Sklar Leonard S.,
Taylor Nicholas J.,
Flinchum Brady A.,
Hayes Jorden L.,
Carr Bradley J.,
Hartsough Peter C.,
O'Geen Anthony T.,
Holbrook W. Steven
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl088322
Subject(s) - weathering , geology , porosity , borehole , seismic refraction , mineralogy , soil science , geomorphology , geophysics , geotechnical engineering
Subsurface weathering has traditionally been measured using cores and boreholes to quantify vertical variations in weathered material properties. However, these measurements are typically available at only a few, potentially unrepresentative points on hillslopes. Geophysical surveys, conversely, span many more points and, as shown here, can be used to obtain a representative, site‐integrated perspective on subsurface weathering. Our approach aggregates data from multiple seismic refraction surveys into a single frequency distribution of porosity and depth for the surveyed area. We calibrated the porosities at a site where cores are coincident with seismic refraction surveys. Modeled porosities from the survey data match measurements at the core locations but reveal a frequency distribution of porosity and depth that differs markedly from the cores. Our results highlight the value of using the site‐integrated perspective obtained from the geophysical data to quantify subsurface weathering and water‐holding capacity.