The 2018 SEG Near-Surface Geophysics Technical Section Proposed Technical Sessions

(Please note, the identified session topics here are not inclusive of all possible near-surface geophysics technical sessions, but have been identified at this point.)

Session topic/title Session description and objective

Coupled above and below-ground Description: There have been significant advances in a variety of geophysical techniques in the past decades to characterize near- monitoring using geophysics, UAV, surface critical zone heterogeneity, including hydrological and biogeochemical properties, as well as near-surface spatiotemporal and remote sensing dynamics such as temperature, soil moisture and geochemical changes. At the same time, above-ground characterization is evolving significantly – particularly in airborne platforms and unmanned aerial vehicles (UAV) – to capture the spatiotemporal dynamics in microtopography, vegetation and others. The critical link between near-surface and surface properties has been recognized, since surface processes dictates the evolution of near-surface environments evolve (e.g., topography influences surface/subsurface flow, affecting bedrock weathering), while near-surface properties (such as soil texture) control vegetation and topography. Now that geophysics and airborne technologies can capture both surface and near-surface spatiotemporal dynamics at high resolution in a spatially extensive manner, there is a great opportunity to advance the understanding of this coupled surface and near-surface system. This session calls for a variety of contributions on this topic, including coupled above/below-ground sensing technologies, new geophysical techniques to characterize the interactions between near-surface and surface environments. Near-surface modeling using Description: The first few meters of the subsurface is of paramount importance to the engineering and environmental industry. tomography Accurate estimations of physical properties are challenging in these areas because of the unconsolidated nature of the material. This even makes lab testing for strength, compaction and porosity very difficult without inducing any disturbances. Using tomography on geophysical data in general, due to their non-intrusive nature and sensitivity to the state of soil/rock consolidation can be a promising tool for investigating the physical properties of this zone. Objectives: 1. To have a common session on tomographic application in near-surface modeling 2. To be able to compare and contrast different tomographic analysis in shallow subsurface characterization, and their pros and cons Petrophysical relationship - link Description: Geophysical tools show the promise to provide spatiotemporal information of subsurface hydrogeological properties in a hydrologic parameters with minimal invasive way. Accurate characterization of subsurface using geophysical tools is challenging due to incomplete understanding geophysical signals of how the highly coupled physical, biological, and geochemical processes occurring spatiotemporally change the geophysical responses. The link between the geophysical signals with subsurface parameters of interests requires understanding of petrophysical relationships and coupled fluid flow and biogeochemical processes. Several petrophysical relationships have been established and most of them are empirical and database dependent. Recently new theoretical or empirical models have been significantly explored to provide mechanical explanation of geophysical responses and/or simulate the effective properties of porous media. This workshop will provide the opportunities for experts in rock physics and anyone who is interested in petrophysical relationships with applications to both hydrogeological investigations. The topics include theoretical developments, laboratory experiments, and field demonstration. Developments and Applications of Description: Active and passive (ambient vibration) surface wave techniques, including the multi-channel analysis of surface Active and Passive Source Surface waves(MASW), spectral analysis of surface waves (SASW), array microtremor, H/V spectral ratio methods have become increasingly Wave Methods popular over the past 15 years. Surface wave measurements may involve acquisition of Rayleigh wave data, Love wave data, or both. Surface wave techniques are often used for site characterization as part of earthquake hazard assessment. Other applications include (Special Session) mapping bedrock and fault zones, compaction control for the pads of critical structures, pavement assessment, levee assessment, geologic site characterization, void mapping, etc.

Objectives: In this session, we welcome presentations on new developments in data acquisition, data reduction and modeling/inversion strategies. Case studies with practical applications of surface wave methods are also welcome. Coastal Zone geophysics Description: The Coastal Zone is one of the most important environments on earth where major cities are heavily populated, and ports and harbors and coastlines include substantial infrastructure necessary for society to survive and enjoy. Because the Coastal Zone spans the region from land to water, there are special requirements for obtaining subsurface information needed to identify and map potential environmental hazards. Site surveys are needed to plan routes for pipelines and other coastal infrastructure, and to locate obstacles for planned construction. Major coastal infrastructure includes energy, transportation, water supply, hydrocarbon production, processing and storage, waste management, and critical defense installations. Due to the difficult data acquisition within the transition zone – where water meets land – the Coastal Zone may be considered the biggest data gap in earth sciences. Consequently, a session to examine numerous examples of data acquisition, processing and interpretation to understand this critical environment and provide important lessons for continued research and commercial projects within the Coastal Zone. Southern California is a natural place to focus attention on Coastal Zone geophysics which are important around the world including all areas where water and land meet – oceans, lakes and rivers.

Objective: The proposed session will provide numerous examples of near surface (and deeper) geophysics used to solve important societal problems including environment, natural hazards, coastal infrastructure, and national defense. Some examples may include coastal energy systems such as offshore wind farms, ocean thermal energy, hydrocarbon production, processing, and storage, water supply (desalination and seawater intrusion), waste treatment and disposal (e.g., CO2 sequestration, sewage, waste water from hydrocarbon production), earthquake, tsunami, storm surge, sea level rise, riverine flooding and water-related hazards to harbors, ports, bridges and other coastal infrastructure, and coastal populations. In addition, the numerous government regulations regarding geophysical work in the sensitive coastal environment need to be addressed and reviewed to help provide a coordinated planning and data acquisition framework for continued successful development and enjoyment of the Coastal Zone. Noise attenuation techniques in Description: Near surface seismic surveys are typically acquired under economic constraints that do not allow for anything approaching near-surface seismic surveys an optimal survey design. In the case of near surface reflection seismic surveys, the observation is frequently made that there is little or no visible signal. The observation could also be made that there is just too much noise. In either case, reducing/attenuating noise in the acquired seismic data is critical in generating interpretable seismic products.

The proposed technical session seeks to merge talks that describe acquisition strategies for improving signal-to-noise in the recorded seismic data with talks that describe processing algorithms and/or strategies for attenuating noise in the processed seismic data.

Objective: The goal of the session will be to highlight the interplay between these aspects of data acquisition and data processing in near surface reflection surveys. The session seeks to have an even distribution of acquisition and processing presentations. Acquisition strategies should be illustrated through case studies. Description: Airborne geophysics uses aircraft, helicopter, or UAV to tow geophysical instruments to do geophysical survey, including Airborne geophysics airborne gravity, magnetics, EM and radiometry. Due to its moving platform, airborne geophysics has been widely used in mountains, deserts, lakes and swamps, and forest-covered areas for mineral exploration, oil & gas, environmental and engineering, groundwater, and ocean investigation, etc. This technology has special usage in NSG due to its high resolution near the Earth’s surface. However, the forward modeling and inversion theory, the instrumentation and the data processing and interpretation are still underdeveloped and have much room for improvement. To set up the session on airborne geophysics in this meeting will certainly help speed up largely the development of this technology.

Near-surface geophysics applied to Description: The search and characterization of earthen archaeological features is an important topic in geophysical prospecting for archaeological research archaeology due to the large temporal and spatial distribution of such type of cultural heritage. Earthen archaeological features include rammed platforms, earth ovens, ancient earth walls, kiln sites, storage pits and tumuli, mostly related to prehistoric settlements. (Special Session) From the point of view of geophysical prospecting, the characterization of earthen archaeological features are challenging because of the limited target/background contrast and the attenuation of the electromagnetic or seismic waves caused by the quaternary sedimentary soils, which are frequently used as building materials due to their mechanical properties. And also the various noises frequently existed in near surface geophysics are the serious problems to suppress. Therefore, it is important to develop new techniques to enhance imaging and characterization of such prehistoric/historic sites, in order to identify and map archaeological remains and optimize archaeological excavation plans. Welcome to the archaeological geophysics session to improve the techniques for exploring the ancient human being life. Description: Recent advances in imaging of the near-surface expression of structures have allowed us to say much more about the Near-surface imaging of structures nature and properties of subsurface structural features that reach or come close to the Earth’s surface. This session on the “state-of- the-art” imaging of near-surface structures will cover the full range of near-surface geophysical methods used for imaging near-surface structures, including electrical, electromagnetic, ground penetrating radar, potential field, and shallow seismic methods. Results of multiparameter studies using complementary methods are particularly encouraged. Site amplification (earthquakes Description: Site amplification caused by excitation of near-surface soil materials and basin sediments is an essential part of engineering/seismology) earthquake hazard/risk assessment. Site effect besides source and path effects is the essential part of an observed ground motion because the soil amplifications may adversely influence the earthquake damage on living environment specifically in urban areas with underlying shallow and deep sediments. This requires collaborations among a spectrum of specialists in earthquake engineering, geophysics and geology. This session welcomes contributions to site amplification studies that target new or improved methods and applications, including physical, numerical, theoretical, multi-method approaches. We also welcome basin or shallow soil amplification studies using geophysical surveys and encourage contributions addressing development and use of community or national database(s) such as seismic-wave velocity profiles or 2D/3D models, and Vs30 m. Description: Soil properties control the ability of the soil to retain water and nutrients that will be available for uptake by the plant. Soil Agricultural geophysics properties of agricultural interest include texture and structure, organic carbon, soil salinity, pH, cation exchange capacity, micronutrients, etc. Precision agriculture involves the identification of variations in field conditions to instruct site-specific applications of agricultural inputs to reduce irrigation water, nutrient, and energy costs while increasing productivity and profitability with minimal environmental impacts. Geophysics provide a unique opportunity to rapidly and inexpensively map spatially continuous variations in soil properties across a field. This session seeks contributions of geophysical applications aimed at improving sub-field, site-specific agricultural management practices. We particularly encourage applications geared toward improving irrigation water and nutrient management practices, water banking, vineyard management, geophysical characterization of soil health, etc. Natural hazard mitigation: Objective: To bring together scientists/research that use geophysics and non-destructive testing to identify material weaknesses and Geophysics and NDT for site and site risks associated with natural hazards, including earthquakes, volcanic eruptions, landslides, fires, and floods. material characterization Description: Natural hazard mitigation refers to work to minimize the potential effects of natural hazards, including earthquakes, volcanic eruptions, landslides, fires, and floods. Geophysical methods and non-destructive testing (NDT) can play an important role in site characterization and assessing strengths and weaknesses of materials and critical infrastructure. This session welcomes abstracts that describe research on the use geophysics and NDT for such studies, specifically in the context of mitigating future hazardous events. The abstracts can focus on field and site investigations, modeling studies, lab tests, or a combination.

Geophysics for study of past Objective: To bring together scientists that use geophysics for the study of past natural disasters and hazardous events, and use such hazardous events (the past is the data to understand the risk of future events. key to the future) Description: Understanding the historical record of past natural hazardous events, including their recurrence interval and magnitude, is an important component of risk assessments and probabilistic estimates of future events. Geophysical methods have the unique ability to locate, image, map, and characterize the products of such past events, including fault offsets of earthquakes, landslide and volcanic eruption deposits, and to the effects of floods and fires. This session welcomes contributions that describe research on the use geophysics for studies of past hazardous events and their effects and products.

Aquifer storage and monitoring - Description: Utilization of geophysical methods to characterize, assess and monitor aquifer storage and recovery (ASR) co-sponsored session with NGWA Objective: Presentations will focus on the application of seismic, electrical, electromagnetic, and gravity methods to characterize hydrogeologic systems designated for ASR development and the use of surface, borehole, and cross-well time-lapse geophysics to monitor emplacement, storage, and extraction of water from ASR systems Hydrologic impacts of natural Description: Application of geophysical methods to characterize hydrogeologic systems impacted by natural resource development and resource extractive activities – co- extraction activities. sponsored session with NGWA Objective: Presentations will focus on the application geophysics to characterize hydrogeologic systems impacted by natural resource extraction activities (e.g. mining, hydrofracing, and produced waters) to include acid mine drainage, brine or other releases from storage ponds, and impacts of reinjection and (or) other production or disposal activities. Hydrogeophysics with emphasis on Description: Utilization of geophysical methods in solving challenges for clean water accessibility. water for humanity Objective: Correlating geophysical methods and geospatial technologies (e.g. remote sensing and geodesy) in near-surface water exploration.

Hydrogeophysics - co-sponsored Description: The Hydrogeophysics special session will highlight papers on the application of near-surface geophysics to hydrologic session with AGU problems. The session will include papers that report new methods for analysis and interpretation of hydrogeophysical data; development of cutting-edge instruments, and presentation of novel case studies. (Special Standing Session)

Engineering geophysics (Special Session) Objective: Presentations will focus on applications of geophysics to engineering. Examples include bedrock imaging for roads and structures, detecting rebar corrosion on bridges, and investigations of soil and rock dynamic properties.

Description: Geophysics is commonly applied to engineering applications. With limited time and money in today's markets, geophysics can often provide a cost-effective means for assessing site conditions, of course always supplemented by ground-truth information commonly derived from boreholes. Relevant topics include engineering geophysical methods, groundwater geophysics, soil characterization and infrastructure geophysics, measurement technology and data processing, and geotechnical procedures such as imaging and monitoring. Description: The application of geophysical tools during the planning and construction of new infrastructure (roads, bridges, tunnels, Infrastructure and underground etc.), as well as the monitoring and assessment of existing infrastructure. tunneling Objectives: Bring together geophysicists and civil engineers to discuss and share experiences in infrastructure problems.

Tunnel and void detection Description: Geophysicists have been trying to locate tunnels since the Korean War, most recently to detect tunnels under the Mexican-American border. The same experiments have been done repeatedly, driven by government funding. A number of methods work when you know the location of the tunnel--you can see it in the data--but when tried in a blind test, lots of artifacts look like tunnels. Finally, some researchers have been able to locate known and unknown tunnels without advance knowledge. Objective: Report on the techniques that actually have worked and perhaps stop repeating the same ineffective experiments.

Geoscientists Without Borders® Description: Geoscientists have the tools needed to effect positive change in communities facing environmental hardship and natural and humanitarian geophysics hazards like severe water shortages and threats of earthquakes, tsunamis and landslides. GWB supports geoscientists globally as they apply their specialized knowledge and technical skills to the mitigation of natural hazards in some of the world's neediest communities. Geophysical tools are a critical part of this effort to understand the shallow subsurface and what it can tell us about the physical, biological and geochemical environment. These tools include electrical, seismic, MASW, magnetic, gravity, and ground penetrating radar methods. Investigation results are then used to build collaborative projects with community residents, local and state governments, other humanitarian organizations, students and scientists to make a significant difference to the lives of those in need. Objective: In this session we welcome presentations and case studies that highlight the use of near-surface geophysics to better understand the subsurface, the risk of natural hazards, and how these risks can be mitigated.

Submit abstracts by 1 April 2018 here.

(NOTE: Near-surface geophysics abstracts other than special sessions should be submitted through the Near Surface topic option.)