{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/34513"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/34513","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Multi-fold TDEM Experiment Design for Near Surface Conductivity Mapping","abstract":"Multi-fold Time Domain Electromagnetics (TDEM) is a novel experimental approach that couples elements of traditional land-based TDEM survey designs to obtain a robust data set. This design inherently accommodates a broad range of possible Earth models through a rich combination of analysis opportunities making it ideally suited for reconnaissance. Kentland Farms, VA was chosen as the test site, for its ease of access and interesting geologic features such as river terraces and karstic landscape. Three independent methods of analyzing the 3-component data set each provided unique insights into the subsurface electrical structure through a complementary interpretation. Synthesis of log-normalized ∂tB<sub>z</sub> pseudo-sections provided a first-order analysis of the lateral and vertical heterogeneities of the profile. A Zero-Crossing Moveout (ZCMO) analysis used a brute-force grid-search inversion to estimate the two-layer Earth model that best-fit the observed moveout times for a range of interface depths. By using the ZCMO result as an initial model, regularized 1D Occam inversions determined a 3-layer electrical structure consisting of a 3.5 m – 5 m thick resistive upper layer, over an 12.5 m – 15 m thick conductive layer, overlying a resistive half-space. From correlation of the inverse solutions with ZCMO derived conductivity models and prior resistivity information, the depth to the limestone bedrock was approximated to be 16 – 20 m. The delineation of the bedrock depth provided additional support for the fill-cut terrace formation model (Ward et al., 2005), as well as possible evidence of groundwater drainage on the 40 m terrace at Kentland Farm.","abstract_html":"Multi-fold Time Domain Electromagnetics (TDEM) is a novel experimental approach that couples elements of traditional land-based TDEM survey designs to obtain a robust data set. This design inherently accommodates a broad range of possible Earth models through a rich combination of analysis opportunities making it ideally suited for reconnaissance. Kentland Farms, VA was chosen as the test site, for its ease of access and interesting geologic features such as river terraces and karstic landscape. Three independent methods of analyzing the 3-component data set each provided unique insights into the subsurface electrical structure through a complementary interpretation. Synthesis of log-normalized ∂tB&lt;sub&gt;z&lt;/sub&gt; pseudo-sections provided a first-order analysis of the lateral and vertical heterogeneities of the profile. A Zero-Crossing Moveout (ZCMO) analysis used a brute-force grid-search inversion to estimate the two-layer Earth model that best-fit the observed moveout times for a range of interface depths. By using the ZCMO result as an initial model, regularized 1D Occam inversions determined a 3-layer electrical structure consisting of a 3.5 m – 5 m thick resistive upper layer, over an 12.5 m – 15 m thick conductive layer, overlying a resistive half-space. From correlation of the inverse solutions with ZCMO derived conductivity models and prior resistivity information, the depth to the limestone bedrock was approximated to be 16 – 20 m. The delineation of the bedrock depth provided additional support for the fill-cut terrace formation model (Ward et al., 2005), as well as possible evidence of groundwater drainage on the 40 m terrace at Kentland Farm.","abstract_has_math":false,"creators":["Kazlauskas, Eric Michael"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Geosciences","degree_department":"Geosciences","school":null,"contributors":[],"advisors":[],"committee_chairs":["Weiss, Chester J."],"committee_members":["Spotila, James A.","Schreiber, Madeline E."],"year":2010,"date_issued":"2010-08-02","date_published":"2010-08-02","updated_at":"2026-07-22T22:20:20Z","subjects":["Zero-crossing moveout","1D inversion","depth to bedrock","Kentland Farms geology","experiment design","time domain electromagnetics","conductivity mapping"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-08132010-142957"],"render_values":[{"text":"etd-08132010-142957","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/34513","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Weiss, Chester J."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Spotila, James A.","Schreiber, Madeline E."]},{"key":"dc:contributor.department","label":"Department","values":["Geosciences"]},{"key":"dc:creator","label":"Author","values":["Kazlauskas, Eric Michael"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:43:23Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:43:23Z","2010-09-07"]},{"key":"dc:date.issued","label":"Date","values":["2010-08-02"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Geosciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Zero-crossing moveout","1D inversion","depth to bedrock","Kentland Farms geology","experiment design","time domain electromagnetics","conductivity mapping"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-08132010-142957"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/34513"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Multi-fold Time Domain Electromagnetics (TDEM) is a novel experimental approach that couples elements of traditional land-based TDEM survey designs to obtain a robust data set. This design inherently accommodates a broad range of possible Earth models through a rich combination of analysis opportunities making it ideally suited for reconnaissance. Kentland Farms, VA was chosen as the test site, for its ease of access and interesting geologic features such as river terraces and karstic landscape. Three independent methods of analyzing the 3-component data set each provided unique insights into the subsurface electrical structure through a complementary interpretation. Synthesis of log-normalized ∂tB<sub>z</sub> pseudo-sections provided a first-order analysis of the lateral and vertical heterogeneities of the profile. A Zero-Crossing Moveout (ZCMO) analysis used a brute-force grid-search inversion to estimate the two-layer Earth model that best-fit the observed moveout times for a range of interface depths. By using the ZCMO result as an initial model, regularized 1D Occam inversions determined a 3-layer electrical structure consisting of a 3.5 m – 5 m thick resistive upper layer, over an 12.5 m – 15 m thick conductive layer, overlying a resistive half-space. From correlation of the inverse solutions with ZCMO derived conductivity models and prior resistivity information, the depth to the limestone bedrock was approximated to be 16 – 20 m. The delineation of the bedrock depth provided additional support for the fill-cut terrace formation model (Ward et al., 2005), as well as possible evidence of groundwater drainage on the 40 m terrace at Kentland Farm."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Multi-fold TDEM Experiment Design for Near Surface Conductivity Mapping"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Weiss, Chester J."],"dc:contributor.committeemember":["Spotila, James A.","Schreiber, Madeline E."],"dc:contributor.department":["Geosciences"],"dc:creator":["Kazlauskas, Eric Michael"],"dc:date.accessioned":["2014-03-14T20:43:23Z"],"dc:date.available":["2014-03-14T20:43:23Z","2010-09-07"],"dc:date.issued":["2010-08-02"],"dc:description.abstract":["Multi-fold Time Domain Electromagnetics (TDEM) is a novel experimental approach that couples elements of traditional land-based TDEM survey designs to obtain a robust data set. 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By using the ZCMO result as an initial model, regularized 1D Occam inversions determined a 3-layer electrical structure consisting of a 3.5 m – 5 m thick resistive upper layer, over an 12.5 m – 15 m thick conductive layer, overlying a resistive half-space. From correlation of the inverse solutions with ZCMO derived conductivity models and prior resistivity information, the depth to the limestone bedrock was approximated to be 16 – 20 m. The delineation of the bedrock depth provided additional support for the fill-cut terrace formation model (Ward et al., 2005), as well as possible evidence of groundwater drainage on the 40 m terrace at Kentland Farm."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-08132010-142957"],"dc:identifier.uri":["http://hdl.handle.net/10919/34513"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Zero-crossing moveout","1D inversion","depth to bedrock","Kentland Farms geology","experiment design","time domain electromagnetics","conductivity mapping"],"dc:title":["Multi-fold TDEM Experiment Design for Near Surface Conductivity Mapping"],"dc:type":["Thesis"],"thesis:degree_discipline":["Geosciences"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:20Z"}