135 research outputs found
Tectonic setting of the kenya rift in the nakuru area, based on geophysical prospecting
In this paper, we present results of tectonic and geophysical investigations in the Kenya Rift valley, in the Nakuru area. We compiled a detailed geological map of the area based on published earlier works, well data and satellite imagery. The map was then integrated with original fieldwork and cross sections were constructed. In key areas, we then performed geophysical survey using Electrical Resistivity Tomography (ERT), Hybrid Source AudioMagnetoTelluric (HSAMT), and single station passive seismic measurements (HVSR). In the study area, a volcano-sedimentary succession of the Neogene-Quaternary age characterized by basalts, trachytes, pyroclastic rocks, and tephra with intercalated lacustrine and fluvial deposits crops out. Faulting linked with rift development is evident and occurs throughout the area crosscutting all rock units. We show a rotation of the extension in this portion of the Kenya rift with the NE-SW extension direction of a Neogene-Middle Pleistocene age, followed by the E-Wextension direction of anUpper Pleistocene-Present age. Geophysical investigations allowed to outline main lithostratigraphic units and tectonic features at depth and were also useful to infer main cataclasites and fractured rock bodies, the primary paths for water flow in rocks. These investigations are integrated in a larger EU H2020 Programme aimed to produce a geological and hydrogeological model of the area to develop a sustainable water management system
A new FSA approach for in situ -ray spectroscopy
An increasing demand of environmental radioactivity monitoring comes both
from the scientific community and from the society. This requires accurate,
reliable and fast response preferably from portable radiation detectors. Thanks
to recent improvements in the technology, -spectroscopy with sodium
iodide scintillators has been proved to be an excellent tool for in-situ
measurements for the identification and quantitative determination of
-ray emitting radioisotopes, reducing time and costs. Both for
geological and civil purposes not only K, U, and Th have
to be measured, but there is also a growing interest to determine the
abundances of anthropic elements, like Cs and I, which are used
to monitor the effect of nuclear accidents or other human activities.
The Full Spectrum Analysis (FSA) approach has been chosen to analyze the
-spectra. The Non Negative Least Square (NNLS) and the energy
calibration adjustment have been implemented in this method for the first time
in order to correct the intrinsic problem related with the
minimization which could lead to artifacts and non physical results in the
analysis.
A new calibration procedure has been developed for the FSA method by using in
situ -spectra instead of calibration pad spectra. Finally, the new
method has been validated by acquiring -spectra with a 10.16 cm x 10.16
cm sodium iodide detector in 80 different sites in the Ombrone basin, in
Tuscany. The results from the FSA method have been compared with the laboratory
measurements by using HPGe detectors on soil samples collected in the different
sites, showing a satisfactory agreement between them. In particular, the
Cs isotopes has been implemented in the analysis since it has been
found not negligible during the in-situ measurements.Comment: accepted by Science of Total Environment: 8 pages, 10 figures, 3
table
Spatio-temporal ground displacements monitoring of the Corniglio landslide (Parma, Italy)
Abstract Number: GHZ05812
Interdisciplinary approach for geomorphological study of an high slope instability area in the northern Apennines mountains
Abstract Number: GSM01319
Analisi dei cambiamenti di uso del suolo nell’area montuosa e collinare dell’Emilia-Romagna nel periodo 1954-1994
Lo scopo di questo studio è stato la realizzazione di una banca dati multitemporale di uso del suolo per i territori montuosi e collinari della Regione Emilia-Romagna, relativa al periodo 1954-1994. Tale banca dati riporta gli attributi relativi all’uso del suolo del 1954-55 e 1994 e consente di analizzare i cambiamenti di estensione, tipologia e localizzazione delle classi di uso del suolo. I dati più recenti sono quelli relativi alla banca dati vettoriale di uso del suolo del 1994 già pubblicata
dalla Regione Emilia-Romagna. I dati del 1954 sono stati ottenuti dall’interpretazione e delineazione visuale di ortofoto ottenute da foto aeree pancromatiche del volo G.A.I. del 1954- 1955. È stata utilizzata una nomenclatura di uso del suolo a priori gerarchica a due livelli comparabile con quella della banca dati del 1994. I risultati dimostrano che in quaranta anni, l’area indagata ha subito una significativa evoluzione di uso del suolo. Le aree a seminativo ed a foresta sono aumentate, a scapito delle aree a coltivazione parcellizzata e specializzata e di cespuglieto
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