GEOPHYSICAL INVESTIGATIONS AT NAFPLION CITY, GREECE. HYDROGEOLOGICAL IMPLICATION

The application of selected geophysical methods within the framework of an Urban Geology investigation program performed by IGME at Nafplion city, contributed to the overall geo-scientific characterization of the study area. The methodology adopted included the application of Time Domain Electromagnetic, Electrical resistivity tomography, Gravity and Seismic Crosshole surveys. The results of the geophysical investigation provided quantitative information regarding the distribution of seawater intrusion in the area and determined factors controlling its extent within the investigated region. The intrusion may occur in three distinct horizons. The first within the shallow unconfined aquifer within the top 12 meters of fluvial deposits showing values of electrical conductivity in the range of 1 and 4 Siemens/m, corresponding to TDS values between 5000 and 20000 mg/L, as determined by the TEM surveys. Lower conductivity values between 0.3 and 1 Siemens/m are found within the second aquifer occurring between 15 and 45 meters. Similar order of conductivity values are found within the deeper horizon, lying below 45 meters depth, attributed also to seawater intrusion mainly in carbonate formations. Areas of fresh groundwater, were delineated by a combination of TEM, ERT and gravity methods. These areas are structurally controlled by faults and the presence of impermeable flysch overlying the limestone formation

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LIQUEFACTION RISK ASSESSMENT BY THE USE OF GEOPHYSICAL TECHNIQUES: THE TEST AREA OF NAFPLION CITY, GREECE

An efficient and cost effective site characterization, with regard to the seismic hazard and liquefaction risk assessment, was accomplished with the aid of geophysics in the area, where the Nafplion city of Greece is expanding. The methodology adopted includes the recognition of the possible earthquake sources of the wider region, their modelling, in order to stochastically simulate the strong ground motion at the investigation area, and finally the calculation of the liquefaction risk. The investigation area was suspected of high liquefaction potential since the foundation ground consists of loose sandy silt with very shallow aquifer. The geophysical techniques considerably contributed to the detection and characterization of possible local seismic faults with the implementation of gravity and seismic methods. Special emphasis was given to the seismic depth migration and particularly to the construction of valid velocity models, in order to precisely calculate the dips of the possible faults. Additionally the geophysical techniques provided the near surface velocity structure for the calculation of the amplification of the seismic motion up to the surface, also required for the final estimation of the liquefaction risk. The seismic methods (seismic reflection, seismic refraction, seismic modelling, MASW, multichannel analysis of microtremors and crosshole investigations), if combined with geo-technical borehole testing, enhance their reliability and cover large areas in a cost-effective way in comparison with the standard borehole tests. In Nafplion area, evidence was found for a low factor of safety against liquefaction at specific sites within the study area. The results show that liquefaction probability can reach 80% at some sites depending on selected earthquake scenario, mainly at depths between 5 and 10 meters. This should be considered as highly important information for making risk-based design decision in this region

GEOPHYSICAL INVESTIGATIONS AT NAFPLION CITY, GREECE. HYDROGEOLOGICAL IMPLICATION

The application of selected geophysical methods within the framework of an Urban Geology investigation program performed by IGME at Nafplion city, contributed to the overall geo-scientific characterization of the study area. The methodology adopted included the application of Time Domain Electromagnetic, Electrical resistivity tomography, Gravity and Seismic Crosshole surveys. The results of the geophysical investigation provided quantitative information regarding the distribution of seawater intrusion in the area and determined factors controlling its extent within the investigated region. The intrusion may occur in three distinct horizons. The first within the shallow unconfined aquifer within the top 12 meters of fluvial deposits showing values of electrical conductivity in the range of 1 and 4 Siemens/m, corresponding to TDS values between 5000 and 20000 mg/L, as determined by the TEM surveys. Lower conductivity values between 0.3 and 1 Siemens/m are found within the second aquifer occurring between 15 and 45 meters. Similar order of conductivity values are found within the deeper horizon, lying below 45 meters depth, attributed also to seawater intrusion mainly in carbonate formations. Areas of fresh groundwater, were delineated by a combination of TEM, ERT and gravity methods. These areas are structurally controlled by faults and the presence of impermeable flysch overlying the limestone formation.</jats:p

ARIES Research Summary

In the mid-2000s, concerns were raised about the impact of Appalachian coal mining and especially mountaintop mining. These concerns were prompted by various research studies that alleged a direct link between coal mining and various negatively trending aspects of community health. Some studies related coal mining to higher rates of cancer and infant mortality. Other investigations claimed that coal mining perpetuated poverty and harms community character. These alarming reports prompted a significant public outcry that resulted in litigation and regulatory attention toward the coal industry. In response, a number of meetings and strategic sessions were held in 2009 and 2010 to address these concerns. Major Appalachian coal producers, coal associations, and essential coal infrastructure companies participated in these conferences. After rigorous debate, the participants decided to form an independent research program designed to address community concerns through objective, focused research. This program was designated the Appalachian Research Initiative for Environmental Science (ARIES). ARIES would be a research consortium designed to elicit the participation of major research universities across the U.S. The primary objective of this research collaboration would be to investigate the impacts of coal mining and energy production on Appalachian communities. To support this goal, ARIES adopted a research paradigm that delivered objective, robust, and transparent results though the support of industry. This paradigm was composed of four core principles: 1. Independent research conducted at universities 2. Wide dissemination of results through peer-reviewed publications 3. Realistic timeframes for research and reporting 4. Applying sound scientific principle

ARIES Executive Summary

The following document contains an executive summary of key findings from the Appalachian Research Initiative for Environmental Science (ARIES). Further details for these findings may be found in the referenced peer-reviewed publications and project reports. The ARIES body of work was developed from 2011 to 2016. Thus, published ARIES results will not reflect any evolutions in policy and research that occurred after this timeframe. Although some issues may be different today, the breakthrough research conducted by the ARIES community continues to provide invaluable insights into these areas of interest