Supervisors info:
Πούλος Σεραφείμ (Επιβλέπων), Καθηγητής, Τμήμα Γεωλογίας και Γεωπεριβάλλοντος, ΕΚΠΑ
Αλεξόπουλος Ιωάννης, Επίκoυρος Καθηγητής, Τμήμα Γεωλογίας και Γεωπεριβάλλοντος, ΕΚΠΑ
Βασιλάκης Εμμανουήλ, Επίκουρος Καθηγητής, Τμήμα Γεωλογίας και Γεωπεριβάλλοντος, ΕΚΠΑ
Summary:
This master’s thesis refers to the research carried out in the deltaic area of the Pinios River in the framework of two research programs of the Department of Geology and Geoenvironment. The title of the thesis is: INVESTIGATION OF THE PHYSICAL-GEOGRAPHICAL CHARACTERISTICS OF THE PINIOS RIVER DELTAIC PLAIN (THESSALY) WITH REMOTE SENSING TECHNIQUES (NEAR SURFACE GEOPHYSICS - SATELLITE IMAGE PROCESSING).
Investigation of the physical-geographical characteristics of the Pinios river deltaic plain (Thessaly) with remote sensing techniques (near surface geophysics - satellite image processing).
The first objective of the thesis, regarding the surface investigation of the area, was to identify the appropriate combination of spectral bands / spectral indices to highlight various biotic / abiotic characteristics of the deltaic plain. For this purpose, we used a very high resolution WordlView-2 image, acquired on 27/07/2013. The multispectral imagery was at 2 m resolution and the panchromatic imagery was at 50 cm resolution. The processing of WorldView-2 satellite images was performed with the ERDAS Imagine 2014 software. As a result, six false color composites of the area were produced combining spectral channels and additional five false color composites by combining several spectral indices.
The second objective, regarding the subsurface survey, was to calculate the thickness of deltaic deposits with geophysical survey. A total of 127 Transient Electromagnetic (TEM) soundings were carried out using ABEM’s electromagnetic device WalkTEM and ViewTEM software for data processing. The evaluation of the geophysical data was completed with the assistance of available drilling data from Institute of Geology and Mineral Exploration (I.G.M.E.). The next step for data management, better visualization and comprehension was RockWorks15 software, with popular tools such as logs, solid models, cross sections and fence diagrams.
The presentation of the final results was done in both two-dimensional (2D) and three-dimensional (3D) environment using the ESRI’s Geographic Information System, ArcGIS Pro. Several maps were constructed regarding the distribution of the lithological units of the area and the thickness of the deltaic deposits. Also, a statistical analysis was performed for each lithological unit and the ratio between them was also calculated.
Regarding the surface investigation of the area we came up with the following conclusions:
• It is advisable to use the combination of spectral channels (7,6,5) to distinguish between land uses and crops (conifers, grass and crops, barren soils)
• It is advisable to use the combination of spectral indices (MSR705, R31, WV-II) to greatly outline the hydrographic network of the area due to the strong contrast of the riparian vegetation.
Regarding the subsurface survey, the following conclusions are reached:
1. Alluvial deposits: The average thickness of the formation is 11 m and is hosting the shallow unconfined aquifer. It was formed during the growth of Pinios Delta that began 4-5.000 years BP
2. Clay layer: Impermeable formation with average thickness 32 m, basically represents the pro-deltaic fine-grained deposits of the emerging delta during the Upper Holocene
3. Transgressive deposits: They are consisted mainly of sands and gravels with small amount of clay. The formation is hosting an aquifer, artesian in places, and overlays the Neogene formations which can be considered as the paleosurface during the last glacial period (sea level was 120-130 meters below present-day sea level).
From the statistical analysis of the thickness of each lithological unit of the Deltaic area as well as their ratio the following conclusions were drawn:
• Alluvial deposits: High values of thickness limited to the central part of the deltaic plain in areas with frequent flooding and small values of thickness in the area north in the deltaic plain where many oxbow lakes are present, in the area of the present estuary as well as in the old estuary area, north of the Stomio settlement
• Small thickness values of clay formation mainly in the southern part of the deltaic area near Ossa mountain’s slopes, in the western part in the deltaic area north of the settlement of Omolio and in the north in Paliomana settlement. High values of thickness appear in the eastern part of the Pinios Deltan, at the present estuary area and inland around Kouloura settlement.
The Clay Formation Thickness/Alluvial deposits Thickness ratio gets its maximum values in the areas of the present and the old estuaries (Stomio settlement) as well as further north in the area of Paliomana settlement and the area north with the large number of oxbow lakes.
Keywords:
WorldView-2, multispectral processing, band ratios, electromagnetic, exploration technique, ΤΕΜ
