About

Mark Everett is a Professor and holder of the David Bullock Harris Chair in Geology at Texas A&M University. His research focuses on near-surface applied geophysics, including controlled-source electromagnetics, ground-penetrating radar, electrical resistivity tomography, and geophysical responses of complex geological systems. His recent themes include geoscience onshore-offshore connectivity, ground-penetrating radar imaging of the terrestrial subsurface, and critical mineral requirements for the energy transition. Everett's educational background includes a BSc and MSc in Physics from York University in Canada, completed in 1985 and 1987 respectively, followed by a PhD in Geophysics from the University of Toronto in 1991. His work involves archaeological, geotechnical, and agricultural applications of geophysics, as well as the geophysical responses of complex geological systems. He has contributed to understanding groundwater variability, subsurface imaging, and the geophysical characterization of natural and anthropogenic features.

Research topics

• Geomorphology
• Geotechnical engineering
• Geology
• Paleontology
• Oceanography
• Engineering
• Mining engineering

Selected publications

• Geological and anthropogenic controls on freshwater lens variability in barrier islands: insights from integrated geophysical and hydrogeological surveys

  Journal of Hydrology · 2025-06-01 · 2 citations

  article
  PublisherDOI

• Thresholding and continuous wavelet transform (CWT) analysis of Ground Penetrating Radar (GPR) data for estimation of potato biomass

  Computers and Electronics in Agriculture · 2025-02-19 · 9 citations

  articleOpen access

  Potato (Solanum tuberosum) is widely recognized as the leading vegetable crop in the United States, with millions of tons produced annually. Despite many advancements in cultivars, crop production still suffers from meager progress in the assessment of early maturity. One potential solution to this problem is Ground-Penetrating Radar (GPR), a near-surface geophysical tool that has recently been applied to agriculture for assessment of root systems by detecting dielectric variations in sub-surface and soil layers by means of electromagnetic waves emitted into the ground. This study seeks to assess GPR’s capability to serve as a non-destructive proximal-sensing technique for quantifying potato tuber biomass by estimating the size of potatoes by measuring changes in the reflected GPR signal. Two methods, thresholding analysis and continuous wavelet transform (CWT), were employed in this study to extract features from GPR responses to predict tuber biomass. The dataset was collected in a controlled sandbox system. Thresholding analysis on the interpolated amplitude values yielded significant results, being able to predict tuber biomass with an accuracy of r = 0.82 and R2 = 0.64 based upon Multiple Linear regression. CWT was somewhat less successful, yet still significant, with a prediction accuracy of r = 0.6 and R2 = 0.32. These results indicate that GPR technology is suitable as a decision-support tool for potato breeders seeking to monitor tuber growth. • Ground-penetrating radar (GPR) can non-destructively estimate potato tuber biomass. • Thresholding delivers more accurate biomass predictions than CWT in GPR analysis. • A sandbox system is ideal for testing GPR in controlled agricultural settings. • GPR offers potential for monitoring potato tuber growth in breeding programs.

  PublisherDOI

• Sinkhole formation induced by descending groundwater in a karst aquifer near a limestone quarry

  Earth Surface Processes and Landforms · 2024-10-10 · 11 citations

  articleOpen accessSenior author

  Abstract This study presents case studies conducted in northeast Thailand, where sinkhole collapses have continuously occurred in certain areas. Rapid descent of groundwater in a karst aquifer has the potential to induce sinkhole collapses within the karst morphology. Field investigations have revealed surface expressions of potentially hazardous sinkholes associated with zones of groundwater depression and abandoned groundwater wells. 2D electrical resistivity tomography (ERT) profiles were executed along the trend of such sinkhole collapses. The ERT results were combined to outline potentially dangerous cavities and continuous fractures. Sinkhole collapses in this scenario are primarily induced by groundwater depression and rainfall. Groundwater flows through conduits connecting a quarry with a karst cavern network, and dewatering of the quarry reduces the surrounding groundwater level. Runoff from rainfall percolates within overburden and enters air‐filled cavities. Additionally, quarry blasting activities may cause vibrations that trigger the formation of sinkholes. Observations of surficial collapse features were generally consistent with geophysical ERT‐interpreted subsurface cavities and fractures. Consequently, implementing regulatory measures to restrict the depth of limestone quarrying that affects groundwater levels may be necessary to prevent sinkhole collapses. The sinkhole formation phenomenon underscores a critical link between groundwater fluctuations and the stability of karst landscapes.

  PublisherOA PDFDOI

• Texas Water Observatory: A Distributed Network for Monitoring Water, Energy, and Carbon Cycles under Variable Climate and Land Use on Gulf Coast Plains

  Journal of Hydrometeorology · 2024-09-16 · 2 citations

  article

  Abstract In the Gulf Coastal Plains of Texas, a state-of-the-art distributed network of field observatories, known as the Texas Water Observatory (TWO), is developed to better understand the water, energy, and carbon cycles across the critical zone (encompassing aquifers, soils, plants, and atmosphere) at different spatiotemporal scales. Using more than 300 advanced real-time/near-real-time sensors, this observatory monitors high-frequency water, energy, and carbon storage and fluxes in the Brazos River corridor, which are critical for coupled hydrologic, biogeochemical, and land–atmosphere process understanding in the region. TWO provides a regional resource for better understanding and/or managing agriculture, water resources, ecosystems, biodiversity, disasters, health, energy, and weather/climate. TWO infrastructure spans common land uses in this region, including traditional/aspirational cultivated agriculture, rangelands, native prairie, bottomland hardwood forest, and coastal wetlands. Sites represent landforms from low-relief erosional uplands to depositional lowlands across climatic and geologic gradients of central Texas. We present the overarching vision of TWO and describe site design, instrumentation specifications, data collection, and quality control protocols. We also provide a comparison of water, energy, and carbon budget across sites, including evapotranspiration, carbon fluxes, radiation budget, weather, profile soil moisture and soil temperature, soil hydraulic properties, hydrogeophysical surveys, groundwater levels, and groundwater quality reported at TWO primary sites for 2018–20 (with certain data gaps). In conjunction with various Earth-observing remote sensing and legacy databases, TWO provides a master testbed to evaluate process-driven or data-driven critical zone science, leading to improved natural resource management and decision support at different spatiotemporal scales. Significance Statement We provide the vision, design setup, and data acquisition of a state-of-the-art network of field observatories across the Gulf Coastal Plains of Texas. This observatory provides a wealth of measurements of the water, energy, and carbon fluxes, thereby providing a critical testbed for improving the understanding of terrestrial hydrological, biogeochemical, and atmospheric processes across diverse land-use and climate conditions.

  PublisherDOI

• Integral equation-based wellbore preconditioner for 3D electromagnetic response modeling

  Geophysics · 2024-11-05 · 1 citations

  articleSenior author

  ABSTRACT Modeling subsurface controlled-source electromagnetic (CSEM) responses using the finite-element (FE) method is challenging in the presence of highly conductive wellbore casing. The very large conductivity contrast between the casing and the host formation leads to increased computation time and potentially unstable solutions. We address this difficulty by preconditioning an FE solver with an integral equation (IE) primary solution that captures the CSEM response of a realistic-sized steel wellbore casing. Our hybrid IE-FE approach determines the primary field using 2D IE forward modeling and then interpolates the IE-computed solution onto the nodes. Then, using an existing FE simulator, we solve for the secondary electric and magnetic fields. This approach removes the need for an ultrafine FE mesh around the wellbore, thereby improving the FE solution stability while greatly reducing the FE computation time. Our method is illustrated by modeling the CSEM responses of idealized fluid-bearing zones.

  PublisherDOI

• Texas Water Observatory: A Distributed Network for Monitoring Water, Energy, and Carbon Cycles Under Variable Climate and Land Use on Gulf Coast Plains

  2024-07-15

  preprintOpen access

  In the Gulf Coastal Plains of Texas, a state-of-the-art distributed network of field observatories, known as the Texas Water Observatory (TWO), is developed to better understand the water, energy, and carbon cycles across the critical zone (encompassing aquifers, soils, plants, and atmosphere) at different spatiotemporal scales.Using more than 300 advanced real-time / near-real-time sensors, this observatory monitors high-frequency water, energy, and carbon storage and fluxes in the Brazos River corridor, which are critical for coupled hydrologic, biogeochemical, and land-atmosphere process understanding in the region.TWO provides a regional resource for better understanding and/or managing agriculture, water resources, ecosystems, biodiversity, disasters, health, energy, and weather/climate.TWO infrastructure spans common land uses in this region, including (traditional/aspirational cultivated agriculture, rangelands, native prairie, bottomland hardwood forest, and coastal wetlands).Sites represent landforms from low-relief erosional uplands to depositional lowlands across climatic and geologic gradients of central Texas.We present the overarching vision of TWO and describe site design, instrumentation specifications, data collection, and quality control protocols.We also provide a comparison of water, energy, and carbon budget across sites, including evapotranspiration, carbon fluxes, radiation budget, weather, profile soil moisture and soil temperature, soil hydraulic properties, hydrogeophysical surveys, groundwater levels and groundwater quality reported at TWO primary sites for 2018-2020 (with certain data gaps).In conjunction with various earth-observing remote sensing and legacy databases, TWO provides a master testbed to evaluate process-driven or data-driven critical zone science, leading to improved natural resource management and decision support at different spatiotemporal scales. Significance StatementWe provide the vision, design setup, and data acquisition of a state-of-the-art network of field observatories across the Gulf Coast plains of Texas.This observatory provides a wealth of measurements of the water, energy, and carbon fluxes, thereby providing a critical testbed for improving the understanding of terrestrial hydrological, biogeochemical and atmospheric processes across diverse landuse and climate conditions.

  PublisherOA PDFDOI

• Wavelet Analysis of GPR Data for Belowground Mass Assessment of Sorghum Hybrid for Soil Carbon Sequestration

  Remote Sensing · 2023-08-01 · 3 citations

  articleOpen access

  Among many agricultural practices proposed to cut carbon emissions in the next 30 years is the deposition of carbon in soils as plant matter. Adding rooting traits as part of a sequestration strategy would result in significantly increased carbon sequestration. Integrating these traits into production agriculture requires a belowground phenotyping method compatible with high-throughput breeding (i.e., rapid, inexpensive, reliable, and non-destructive). However, methods that fulfill these criteria currently do not exist. We hypothesized that ground-penetrating radar (GPR) could fill this need as a phenotypic selection tool. In this study, we employed a prototype GPR antenna array to scan and discriminate the root and rhizome mass of the perennial sorghum hybrid PSH09TX15. B-scan level time/discrete frequency analyses using continuous wavelet transform were utilized to extract features of interest that could be correlated to the biomass of the subsurface roots and rhizome. Time frequency analysis yielded strong correlations between radar features and belowground biomass (max R −0.91 for roots and −0.78 rhizomes, respectively) These results demonstrate that continued refinement of GPR data analysis workflows should yield an applicable phenotyping tool for breeding efforts in contexts where selection is otherwise impractical.

  PublisherOA PDFDOI

• Integral equation based wellbore preconditioner for 3D electromagnetic response modeling

  2023-12-14

  articleSenior author

  Modeling subsurface controlled-source electromagnetic (CSEM) responses using the finite-element (FE) method is challenging in the presence of highly conductive wellbore casing. The large conductivity contrast between the casing and the host formation leads to increased computation time and potentially unstable solutions. We address this difficulty by preconditioning a FE solver with an integral equation (IE) primary solution that captures the CSEM response of a realistic-sized steel wellbore casing. Our hybrid IE-FE approach solves the primary field solution using 2-D integral-equation forward modeling and then interpolates the IE-computed solution onto the nodes of a FE mesh. Then using an existing FE simulator, we solve for secondary electric and magnetic field solutions. This approach removes the need for an ultra-fine FE mesh around the wellbore, thereby improving FE solution stability while greatly reducing FE computation time. Our method is illustrated by modeling the CSEM responses of idealized fluid-bearing zones.

  PublisherDOI

• Hydrogeologic controls on barrier island geomorphology: Insights from electromagnetic surveys

  The Leading Edge · 2023-09-01 · 2 citations

  articleSenior author

  Abstract Barrier islands provide a first line of defense for coastal communities against storms, hurricanes, and sea-level rise. The geomorphology of barrier islands exerts a major control on storm impact and island recovery. In turn, barrier island geomorphology is affected by subsurface hydrogeologic conditions. In this study, we investigated the relationship between subsurface hydrogeologic conditions and geomorphology of Padre Island, with a focus on the influence of human development. We measured apparent electrical conductivities using frequency-domain electromagnetic (FDEM) surveys and spatially correlated them with the island's morphology. The latter was generated from a 1 m resolution digital elevation model. Four distinct zones were identified from the observed variations in apparent conductivity and elevation, revealing their inverse correlation. The beach area (Zone I) exhibits the highest apparent conductivity (289.7 ± 66.3 mS/m) and the lowest elevations (1.4 ± 0.2 m). These trends are largely due to the proximity of the beach to saline groundwater and maritime floods. Conversely, the foredune area (Zone II) presents the lowest apparent conductivity (19.0 ± 3.4 mS/m) and the highest elevation (4.5 ± 0.4 m) due to a greater distance from saline waters, deeper groundwater levels, and relatively dry soil conditions. Human development has significantly impacted Zones III (east central zone) and IV (west central zone), contributing to an increase in apparent conductivity (Zone III: 40.3 ± 21.8 mS/m; Zone IV: 159.5 ± 83.0 mS/m) and a reduction in elevation (Zone III: 2.1 ± 0.5 m; Zone IV: 1.3 ± 0.4 m). Anthropogenic activities have modified hydrologic patterns, introduced conductive materials, and altered vegetation cover and soil composition. This research elucidates the interplay between subsurface electrical conductivity, surface morphology, and the impact of human development on barrier island geomorphology, providing crucial insights for coastal management and conservation efforts.

  PublisherDOI

• Modeling of Fiber-optic Strain Response When Pumping Stops to Verify Potential Continuation of Fracture Extension

  2023-01-01 · 3 citations

  articleSenior author
  PublisherDOI

Recent grants

• Collaborative Research: Electromagnetic Induction in Geological Formations: A Careful Evaluation of the Subdiffusion Perspective

  NSF · $151k · 2010–2014

Frequent coauthors

• Carl J. Pierce

  Texas College

  33 shared

• Timothy S. de Smet

  29 shared

• Dana Lee Pertermann

  Southwestern Oregon Community College

  26 shared

• D. B. Dickson

  Texas Tech University

  25 shared

• Bradley A. Weymer

  Shanghai Jiao Tong University

  24 shared

• Phillipe A. Wernette

  Great Lakes Science Center

  18 shared

• Chester J. Weiss

  Sandia National Laboratories

  15 shared

• Potpreecha Pondthai

  Khon Kaen University

  15 shared