Enhanced understanding of subsurface water storage will improve prediction future impacts climate change, including drought, forest mortality, wildland fire, and strained security. Previous research has examined the importance plant‐accessible in soil, but upland landscapes within Mediterranean climates, soil often accounts for only a fraction storage. We draw insights from previous case study Southern Sierra Critical Zone Observatory to define attributes storage; review observed patterns...

Abstract As bedrock weathers to regolith – defined here as weathered rock, saprolite, and soil porosity grows, guides fluid flow, liberates nutrients from minerals. Though vital terrestrial life, the processes that transform into are poorly understood, especially in deep regolith, where direct observations difficult. A 65-m-deep borehole Calhoun Critical Zone Observatory, South Carolina, provides unusual access a complete weathering profile an Appalachian granitoid. Co-located geophysical...

Abstract Observing the critical zone (CZ) below top few meters of readily excavated soil is challenging yet crucial to understanding Earth surface processes. Near‐surface geophysical methods can overcome this challenge by imaging CZ in three dimensions (3‐D) over hundreds meters, thus revealing lateral heterogeneity subsurface properties across scales relevant hillslope erosion, weathering, and biogeochemical cycling. We imaged under a soil‐mantled ridge developed granitic terrain Laramie...

Abstract In high‐mountain watersheds, the critical zone holds crucial life‐sustaining water stores in form of shallow groundwater aquifers. To better understand role that plays moderating hydrologic response to fluxes at surface and subsurface, properties must be characterized over large scales (i.e., watershed). this study, we estimate porosity from geophysical measurements across a 58‐ha area depths ~80 m. Our observations include velocities seismic refraction, downhole nuclear magnetic...

Weathering in the critical zone causes volumetric strain and mass loss, thereby creating subsurface porosity that is vital to overlying ecosystems. We used geochemical geophysical measurements quantify relative importance of loss---the physical chemical components porosity---in weathering granitic saprolite southern Sierra Nevada, California, USA. Porosity decrease with depth imply more than doubles volume during exhumation surface by erosion. Chemical depletion relatively uniform,...

Fractures in Earth's critical zone influence groundwater flow and storage promote chemical weathering. Fractured materials are difficult to characterize on large spatial scales because they contain fractures that span a range of sizes, have complex distributions, often inaccessible. Therefore, geophysical characterizations the depend scale measurements response medium impulses at scale. Using P-wave velocities collected two scales, we show seismic fractured bedrock layer scale-dependent. The...

ABSTRACT In this investigation, we compare the results of electrical resistivity measurements made by six commercially available instruments on same line electrodes to determine if there are differences in measured data or inverted results. These comparisons important whether between different consistent. We also degraded contact resistance one quarter study how each instrument responds connection with ground. find that produced statistically similar apparent results, and any conservative...

Abstract Weathering and hydrological processes in Earth's shallow subsurface are influenced by inherited bedrock structures, such as bedding planes, faults, joints, fractures. However, these structures difficult to observe soil‐mantled landscapes. Steeply dipping with a dominant orientation detectable seismic anisotropy, fast wave speeds along the strike of structures. We measured (~2–4 m) anisotropy using “circle shots,” geophones deployed circle around central shot point, weathered granite...

Abstract 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 and, as shown here, can be used obtain representative, site‐integrated perspective subsurface weathering. Our approach aggregates data from multiple seismic refraction surveys...

Abstract For decades, seismic imaging methods have been used to study the critical zone, Earth's thin, life‐supporting skin. The vast majority of zone studies use traveltime tomography, which poorly resolves heterogeneity at many scales relevant near‐surface processes, therefore limiting progress in science. Full‐waveform tomography can overcome this limitation by leveraging more data and enhancing resolution geophysical imaging. In study, we apply 2D full‐waveform match phases observed...

Core Ideas Unsaturated saprolite, saturated and fractured rock have unique NMR responses. Surface signals will be dominated by water in saprolite. The heterogeneous nature of results low‐amplitude surface signals. Understanding critical zone (CZ) structure below the first few meters Earth's is challenging yet important to understand hydrologic processes that influence life on Earth. Nuclear magnetic resonance (NMR) an emerging geophysical tool can quantify volume groundwater pore‐scale...

Abstract Poisson's ratio for earth materials is usually assumed to be positive (V p /V s > 1.4). However, this assumption may not valid in the critical zone because near Earth's surface effective pressures are low (<1 MPa), porosity has a wide range (0%–60%), there significant texture changes (e.g., unconsolidated vs. fractured media), and saturation ranges from 0% 100%. We present P‐wave ) S‐wave velocities seismic refraction profiles collected weathered crystalline environments South...

Abstract Conceptual uncertainty is considered one of the major sources in groundwater flow modeling. Hypothesis testing essential to increase system understanding by analyzing and refuting alternative conceptual models. We present a systematic approach model aimed at finding an ensemble understandings consistent with prior knowledge observational data. This differs from traditional tuning parameters single conform data through inversion. apply this simplified hydrogeological characterization...

Physical, chemical, and biological processes create maintain the critical zone (CZ). In weathered crystalline rocks, these occur over 10–100 s of meters transform bedrock into soil. The CZ provides pore space flow paths for groundwater, supplies nutrients ecosystems, foundation life. Vegetation in aboveground depends on components actively mediates Earth system like evapotranspiration, nutrient water cycling, hill slope erosion. Therefore, vertical lateral extent can provide insight...

Abstract. Identifying and quantifying recharge processes linked to ephemeral surface water features is challenging due their episodic nature. We use a combination of well-established near-surface geophysical methods provide evidence groundwater connection under small feature in flat, semi-arid region near Adelaide, Australia. seismic survey obtain P-wave velocity through travel-time tomography S-wave the multichannel analysis waves. The ratios between velocities are used calculate Poisson's...

Research Article| January 21, 2014 Validating Nevada ShakeZoning Predictions of Las Vegas Basin Response against 1992 Little Skull Mountain Earthquake Records Brady A. Flinchum; Flinchum aNevada Seismological Laboratory, University Nevada, Reno, 89557 *Now at the Wyoming, Department Geology and Geophysics, Dept. 3006, 1000 E. Avenue, Laramie, Wyoming 82071‐2000. Search for other works by this author on: GSW Google Scholar John N. Louie; Louie Kenneth D. Smith; Smith William H. Savran; Savran...

Abstract The interaction between surface and groundwater plays a key role in riparian ecosystem while the size of has not been typically incorporated into hydrological modelling systems. An extensive geophysical survey composed 25 individual DC electrical resistivity profiles was conducted at Blair–Wallis site Wyoming. observed images show near‐surface aquifer interpreted as saturated alluvium deposit along channel, rather than geological bedrock. Based on images, it can be inferred that...

Surface-wave methods are classically used to characterize shear (S-) wave velocities ([Formula: see text]) of the shallow subsurface through inversion dispersion curves. When targeting 2D structures with sharp lateral heterogeneity, windowing and stacking techniques can be implemented provide a better description [Formula: text] variations. These techniques, however, suffer from trade-off between resolution depth investigation (DOI), which is well-known when using multichannel analysis...

The Aboriginal population of the Aṉangu Pitjantjatjara Yankunytjatjara (APY) lands in South Australia is dependent on groundwater for nearly all water needs. In that region, placement wells productive aquifers appropriate quality challenging because lack hydrologic data and variable aquifer properties. It desirable to have an improved ability identify evaluate resources this remote region with cost-effective methods make minimal impact environment. A project supported by Society Exploration...

This study explores the impact of deep ( >5 m) critical zone (CZ) architecture on vegetation distribution in a semi-arid snow-dominated climate. Utilizing seismic refraction surveys, we identified significant correlation between saprolite thickness and LiDAR-derived canopy heights (R²=0.47). We argue that CZ structure, specifically shallow fractured bedrock under valley bottoms, redirects groundwater to locations where trees are established—suggesting they located specific with access...

This study explores the impact of deep ( >5 m) critical zone (CZ) architecture on vegetation distribution in a semi-arid snow-dominated climate. Utilizing seismic refraction surveys, we identified significant correlation between saprolite thickness and LiDAR-derived canopy heights (R²=0.47). We argue that CZ structure, specifically shallow fractured bedrock under valley bottoms, redirects groundwater to locations where trees are established—suggesting they located specific with access...

The Anangu Pitjantjatjara Yankunytjatjara (APY) Lands of South Australia is an arid environment and the population relies largely on groundwater resources for potable water agricultural needs. Historically, locating productive wells in region has been hit-and-miss even if a source was found, quality may be unreliable. In this project, we seek to improve security APY lands by demonstrating that surface Nuclear Magnetic Resonance (NMR) Time-Domain Electromagnetic (TEM) geophysical measurements...