| Abstract |
Poisson's ratio for earth materials is usually assumed to be positive (V p /V s > 1.4). However, this assumption may not be valid in the critical zone because near Earth's surface effective pressures are low (<1 MPa), porosity has a wide range (0%–60%), there are significant texture changes (e.g., unconsolidated vs. fractured media), and saturation ranges from 0% to 100%. We present P‐wave (V p ) and S‐wave (V s ) velocities from seismic refraction profiles collected in weathered crystalline environments in South Carolina and Wyoming. Our data show that ∼20% of the subsurface has negative Poisson's ratios (V p /V s values < 1.4), a conclusion supported by borehole sonic logs. The low V p /V s values are confined to the fractured bedrock and saprolite. Our data support the hypothesis that weathering‐generated microcracks can produce a negative Poisson's ratio and that V p /V s values can thus provide insight into important critical zone weathering processes. |
| Authors |
B. A. Flinchum  , Dario Grana  , Bradley J. Carr , Nadarajah Ravichandran , Benjamin J Eppinger , W. Steven Holbrook
|
| Journal Info |
American Geophysical Union | Geophysical Research Letters , vol: 51
, iss: 2
|
| Publication Date |
1/19/2024 |
| ISSN |
0094-8276 |
Type |
article |
| Open Access |
hybrid
|
| DOI |
https://doi.org/10.1029/2023gl105946 |
| Keywords |
Frictional Properties (Score: 0.502453)
|
