Ground-penetrating radar in Estonia: from fieldwork to open data reuse
Date
2023-04-18
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Abstract
Georadar on geofüüsikaline seade, mis võimaldab uurida pinnast kaudselt. Maapinda suunatud ja erinevatelt pindadelt tagasipeegeldunud signaalidest koostab radar pidevad läbilõiked (pildid). Koos paljanditest ja puursüdamikest saadud otseste vaatlusandmetega aitavad radaripildid täiendada meie ettekujutust maapõuest.
Doktoritöö selgitab georadari potentsiaali erinevates settekeskkondades ning teeb ettepanekuid seadme laialdasemaks kasutamiseks. Autori kogemustele ja kirjandusallikatele tuginedes on soovitatav georadarit tarvitada geoloogilisel kaardistamisel ja maavarauuringutel. Seade aitab piiritleda turba, liiva, kruusa, moreeni ja lubjakivi levikut ning kirjeldada mitmesuguseid rikkestruktuure. Samuti on võimalik täpsustada maavarade levikut, mahtu ja kvaliteeti. Keerulisema maapõueehituse korral saab georadariga optimeerida puurimiskulusid ning suurendada kaevandamistulusid.
Doktoritöö annab ülevaate Eesti radariuuringutest. Töö aluseks oleva nelja uuringu andmed on avalikustatud Maa-ameti geoportaalis. Lähiaastatel plaanib Maa-amet võtta kasutusele riikliku kaardistusplatvormi Geo3D, mille maapõuemudelisse on oodatud kõikide radariuuringute info. Suurema ühtlustatud andmekogumiga saaks arendada masinõpet, mis aitaks säästa radaripiltide tõlgendamisele kuluvat aega. Piltidel tuvastatud objektid koos muude Geo3D avaandmetega on väärtuslikuks sisendiks järgnevatele pinnaseuuringutele.
Ground-penetrating radar is a geophysical device for indirect subsurface studies. Signals transmitted into the ground, and reflected back from different surfaces, allow the construction of continuous cross-sections (radar images). Hence the geological realm, generally known from the boreholes and outcrops, obtains a more consistent perception. The thesis specifies the radar potential in various depositional environments and provides recommendations for its additional applications. Based on the author's experiences and examined references, more intensive radar usage is promoted in two fields – geological mapping and mineral resource estimations. The method can successfully reveal the distribution of peat, sand, gravel, till, carbonate rocks, as well as various deformation structures. Similarly, the tool enables to adjust the mineral resource's spatial extent, quality, and quantity. In more complicated circumstances, the exploration costs can be decreased, whereas the extraction profits may increase with radar engagement. The thesis gives an overview of the Estonian radar surveys. The results of the four case studies are shown in the Estonian Land Board's geoportal. In the coming years, the Land Board will launch the new mapping environment Geo3D. All the radar interpretations are welcome to the Geo3D subsurface module. Larger standardised datasets allow developing machine learning procedures, thus reduce analysis time. Objects identified in the radar images along with other Geo3D open data become valuable inputs for the subsequent geological explorations.
Ground-penetrating radar is a geophysical device for indirect subsurface studies. Signals transmitted into the ground, and reflected back from different surfaces, allow the construction of continuous cross-sections (radar images). Hence the geological realm, generally known from the boreholes and outcrops, obtains a more consistent perception. The thesis specifies the radar potential in various depositional environments and provides recommendations for its additional applications. Based on the author's experiences and examined references, more intensive radar usage is promoted in two fields – geological mapping and mineral resource estimations. The method can successfully reveal the distribution of peat, sand, gravel, till, carbonate rocks, as well as various deformation structures. Similarly, the tool enables to adjust the mineral resource's spatial extent, quality, and quantity. In more complicated circumstances, the exploration costs can be decreased, whereas the extraction profits may increase with radar engagement. The thesis gives an overview of the Estonian radar surveys. The results of the four case studies are shown in the Estonian Land Board's geoportal. In the coming years, the Land Board will launch the new mapping environment Geo3D. All the radar interpretations are welcome to the Geo3D subsurface module. Larger standardised datasets allow developing machine learning procedures, thus reduce analysis time. Objects identified in the radar images along with other Geo3D open data become valuable inputs for the subsequent geological explorations.
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Väitekirja elektrooniline versioon ei sisalda publikatsioone
Keywords
geological surveys, open data, data processing, Estonia, ground-penetrating radar