{"id":5235,"date":"2013-08-20T10:24:20","date_gmt":"2013-08-20T14:24:20","guid":{"rendered":"http:\/\/www.l-a-k-e.org\/blog\/?p=5235"},"modified":"2013-08-26T14:40:01","modified_gmt":"2013-08-26T18:40:01","slug":"karst-subsidence-beneath-a-house-in-lowndes-county-don-thieme-lcc-2013-08-13","status":"publish","type":"post","link":"http:\/\/www.l-a-k-e.org\/blog\/2013\/08\/karst-subsidence-beneath-a-house-in-lowndes-county-don-thieme-lcc-2013-08-13.html","title":{"rendered":"Karst subsidence beneath a house in Lowndes County –Don Thieme @ LCC 2013-08-13"},"content":{"rendered":"

\r\nReceived yesterday on\r\n\r\nFlorida sinkholes spreading real estate effects in same Aquifer as under Lowndes County<\/a>. -jsq\r\n

\r\n\r\n\"Scanning\"<\/a>\r\nJohn — Thank you for pressing forward on this important issue for the\r\nairmen and their families at Moody AFB as well as for all citizens of\r\nLowndes County. My colleagues and I are also concerned and hope that we\r\ncan eventually obtain the Phase I geotechnical study. Of course, we have\r\nour own research agendas as well as a desire to see our students working\r\non these problems close to their own university campus. In particular,\r\none of my undergraduate students just completed his thesis on karst\r\nsubsidence beneath a house in Lowndes County. Here is a link to a poster\r\nwhere he presented those finding to our undergraduate research conference:\r\n\r\nGPR Investigation of Subsidence<\/a>.\r\n

\r\n-Don Thieme\r\n<\/blockquote>\r\n

\r\n

\r\nGround-Penetrating Radar Investigation of Subsidence\r\n
\r\nin Covered Karst near Valdosta\r\n<\/H2>\r\nBenjamin Davis, Department of Physics, Astronomy, and Geosciences\r\n
\r\nFaculty Sponsor: Donald M. Thieme\r\n

\r\nAbstract\r\n<\/H3>\r\n

\r\nWe employed Ground-Penetrating Radar (GPR) to\r\ninvestigate a house lot in a rural area west of\r\nvaldosta at which subsidence had occurred.\r\nsubsurface anomalies were identined in a 29 x 51\r\nm grid which abutted the house. Two other areas\r\non the same property were also investigated to\r\nidentify locations which had fewer subsurface\r\nanomalies and might be less prone to subsidence\r\nthan the current house site. The land surface on\r\nthe property is variably mantled by indurated\r\nsand at the top ofthe Hawthorne Group in the\r\nlocal geology. soil auger samples taken from\r\nwithin the grid correspond to differences in radar\r\nwave velucity along specinc profiles. The entire\r\ngrid of 29 profiles was combined to prepare\r\n\u201dTime Slice\u201d maps, which can then be imaged in\r\na single 3D block diagram. Time-Slice GPR analysis\r\nshows promise for estimating the likelihood of\r\nsubsidence in the Valdosta area.\r\n

\r\n\r\n\"Subsidence\"<\/a>\r\n

\r\nWatkins site\r\n<\/H3>\r\nThe area north of the house site (WAT) is the location\r\nof the 29 x 51 m grid where this investigation\r\nidentified subsidence related to the structural damage\r\nto the house itself. Two areas to the south and west of\r\nthe original house were investigated as locations\r\nwhich the owner was interested in moving his house\r\nto.\r\n

\r\n\r\n\"Location\"<\/a>\r\n

\r\nGround-Penetrating Radar [GPR)\r\n<\/H3>\r\n

\r\nGPR is an active geophysical technique using the radio frequency portion of Electromagnetic\r\nspectrum at wavelengths from 0.3 to 3000m. In the present study we used a MALA 100 MHz\r\nGPR system.\r\nChanges in sediment type or degree of compaction are recorded when the\r\nradar wave is reflected back to the antenna. Areas of subsidence such as sinkholes in karst\r\nregions can be identi\ufb01ed. GPR results for the Watkins property provide strong evidence for\r\nthe subsidence which already affected the house site.\r\n

\r\n\r\n\"2D\"<\/a>\r\n

\r\nGPR Software\r\n<\/H3>\r\n

\r\nGPR pro\ufb01les were collected in the\r\n\ufb01eld using RAMAC Groundvision<\/em> GPR\r\nMeasurement software in order to\r\nmake 1D images. we used GPR-Slice\r\nsoftware to turn our 2D images into\r\n3D models to generate a visible\r\ndegree of depth of subsidence on the\r\nWatkins property.\r\n

\r\n\r\n\"3D\"<\/a>\r\n

Conclusion<\/H3>\r\n

\r\nIn conclusion, we ran two field investigations where we identified multiple subsurface\r\nanomalies trending beneath and around the foundation of the house using\r\nGround-Penetrating Radar (GPR). Following our fieldwork we determined that the\r\ntwo new lots that\r\nwere scanned using GPR were resting on top of indurated sand and clay of the Hawthorne\r\nGroup which is more stable.\r\n

\r\n\r\n\"Poster\"<\/a>\r\n<\/blockquote>","protected":false},"excerpt":{"rendered":"Received yesterday on Florida sinkholes spreading real estate effects in same Aquifer as under Lowndes County. -jsq John — Thank you for pressing forward on this important issue for the airmen and their families at Moody AFB as well as for all citizens of Lowndes County. My colleagues and I are also concerned and hope […]","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"_links_to":"","_links_to_target":""},"categories":[14,2,88,570,571,73,289,6114,3,134,55],"tags":[6813,6842,6841,8704,213,8701,6843,6833,8699,10,6839,8702,91,12,7,8734,8783,8784,4,8731,8758,208,6844,6840,8700,6,8743,8727],"class_list":["post-5235","post","type-post","status-publish","format-standard","hentry","category-economy","category-government","category-lowndes-county-commission","category-military","category-moody-afb","category-safety","category-science","category-sinkhole-2","category-transparency","category-vsu","category-water","tag-13-august-2013","tag-benjamin-davis","tag-donald-m-thieme","tag-economy","tag-geology","tag-georgia","tag-geosciences","tag-geotechnical-study","tag-government","tag-gretchen-quarterman","tag-karst","tag-lake","tag-lcc","tag-lowndes-area-knowledge-exchange","tag-lowndes-county","tag-lowndes-county-commission","tag-military","tag-moody-afb","tag-regular-session","tag-safety","tag-science","tag-sinkhole","tag-sinkholes","tag-subsidence","tag-transparency","tag-valdosta","tag-vsu","tag-water"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p585fK-1mr","jetpack_sharing_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"http:\/\/www.l-a-k-e.org\/blog\/wp-json\/wp\/v2\/posts\/5235","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.l-a-k-e.org\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.l-a-k-e.org\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.l-a-k-e.org\/blog\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"http:\/\/www.l-a-k-e.org\/blog\/wp-json\/wp\/v2\/comments?post=5235"}],"version-history":[{"count":5,"href":"http:\/\/www.l-a-k-e.org\/blog\/wp-json\/wp\/v2\/posts\/5235\/revisions"}],"predecessor-version":[{"id":5327,"href":"http:\/\/www.l-a-k-e.org\/blog\/wp-json\/wp\/v2\/posts\/5235\/revisions\/5327"}],"wp:attachment":[{"href":"http:\/\/www.l-a-k-e.org\/blog\/wp-json\/wp\/v2\/media?parent=5235"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.l-a-k-e.org\/blog\/wp-json\/wp\/v2\/categories?post=5235"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.l-a-k-e.org\/blog\/wp-json\/wp\/v2\/tags?post=5235"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}