The study area of Rodafnidia on the island of Lesbos (Greece) is considered of archaeological interest, as Paleolithic stone tools have been recovered through excavation and collected from the ground surface in recent years. Geologically, the area is mostly covered by Quaternary post-alpine deposits and volcanic rocks. This paper presents the application of a local geophysical survey to determine the volume of the upper Quaternary deposits in which the Paleolithic artefacts can be found and the identification of their ignimbrite substrates. For this reason, the geoelectrical method was selected as the most appropriate for determining the lithostratigraphic subsurface layers. More specifically, a grid of twenty-one (21) Vertical Electrical Soundings (VES) along with an Electrical Resistivity Tomography (ERT) was carried out. The interpretation of the results of these surveys, in conjunction with the results of older excavation trenches, revealed that the Quaternary deposits have been investigated at depths ranging from 0.5 up to 28.5 meters. Furthermore, the lithological boundary of these post-alpine deposits and their underlying pyroclastic ignimbrite flow (with resistivity 24.0–58.0 Ohm.m) seem to dip to the north. The volume of the Quaternary layer is proposed as the maximum depth for archaeological investigation with high chances to recover more Paleolithic material.

The coastal environment of the west and south coast of Peloponnesus, Greece is characterized as an essentially tideless coastal environment exposed to high wave activity. Regarding the identification, the thickness and characteristics of the uppermost substratum of the selected coastal zones, at Hellonitis, Kyparissiakos and Messiniakos Gulfs, a detailed geophysical research was carried out. The geophysical survey aims to determine the thickness and the characteristics of the upper substratum of the selected coastal area, leading to the quantification of the sediment budget; the latter is considered essential to address potential coastal erosion. For this reason, the geophysical techniques of Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) were implemented to profiles normal and parallel to the shoreline. The geophysical results reveal the presence of the interface between the dry and wet sand deposits, along with the structure and the downward extension of the coastal material.

The tool assesses natural factors and the impact of human activities as well as the available mitigation measures in a cost-benefit perspective and with a view to mitigating the impacts of climate change. Therefore, the tool is designed to respond to both erosion (as a natural disaster) and erosion due to human (inappropriate) intervention, as well as CM&D (eg, sea level rise, extreme wave events). The innovation of the project is based on the creation of a multi-parameter decision making tool (ILIDA_KIT) related to climate change mitigation and resilience to coastal erosion and extreme wave events in the context of integrated coastal zone management. ILIDA_KIT relies on a multi-disciplinary interactive platform in a GIS environment that through the development of a set of appropriate indicators (environmental, anthropogeographic, economic) can be parameterised. The ultimate purpose of the tool is to select the most appropriate intervention (intensity, size, time horizon) measure, based on the costbenefit analysis, considering both the protection and the sustainable development of the coastal zone.

This paper presents the methodology of an applied geophysical and remote sensing research at river deltas for their subsurface and surface structure and its application in the deltaic plain of Pineios River (Thessaly, Greece). The scope is to primarily calculate the thickness of deltaic post alpine deposits, with the contribution of Transient Electromagnetic Method (TEM), but also identify the surficial characteristics (biotic/ abiotic) of the area with the appropriate combination of spectral bands and spectral indices. Regarding the remote sensing approach, some geomorphological features were outlined. This was managed from six false color composites of the area, produced by combining spectral bands and additional five false color composites by combining several spectral indices. •The results of the TEM method along with their statistical analysis provided important information regarding the spatial distribution and thickness of the lithological units along the deltaic plain.•The combination of spectral bands 8, 7, 6 seems to adumbrate the hydrographic network of the area and even detects possible changes in the inflow.•The combination of spectral indices MSAVI2, WV-BI, WV-WI was helpful enough to geomorphological mapping of the deltaic plain.

The Athenet network is the network of the Seismological Laboratory of the National and Kapodistrian University of Athens. We present the geophysical investigation that has been carried out at six seismological stations of the Athenet network for their site characterization. More specifically, at the location of each seismological station, four geophysical methods have been carried out: Seismic Refraction Tomography (SRT), Multichannel Analysis of Surface Waves (MASW), the Horizontal to Vertical Spectral Ratio (HVSR) technique, and Electrical Resistivity Tomography (ERT). The applied geophysical survey provided important information regarding the site characterization at the selected seismological stations, including key parameters such as the fundamental frequency fo, the shear-wave velocity VS, the average shear-wave velocity for the upper 30 m depth (VS30), the seismic bedrock depth, the soil type, and the subsurface geology. Moreover, selected elastic moduli (Poisson’s ratio, shear, bulk, and Young moduli) have been calculated. The site characterization information contributes to the determination of the amplification factors for each site that can lead to more accurate calculation of Peak Ground Acceleration (PGA) or Peak Ground Velocity (PGV) and, therefore, trustworthy Probabilistic and Stochastic Seismic Hazard Assessments. The derived fundamental frequency for the seismological stations of VILL, LOUT, THAL, and EPID have been determined to be equal to 10.4, 2.7, 1.4, and 7.1 Hz and their amplification factors to be 1.9, 3.1, 1.7, and 2.6, respectively. For stations MDRA and ATAL, these parameters could not be determined.

In this paper, we present a systematic GIS-based approach for producing updated, upscaled, unified and reevaluated maps for the Ionian Islands of Greece, which is an area of great geological interest. In particular, Cephalonia and Lefkada are two islands with an increased and intense seismicity. Therefore, a common GIS geodatabase was produced for handling the geoinformation of the area. New upscaled (scale 1:50,000) geotechnical and seismotectonic maps of these islands were produced based on older ones. On the other hand, the corresponding maps of the islands, based on the categories of the Greek antiseismic code and Eurocode 8, were produced in an effort to correlate them. Beyond that, all the available isoseismal maps of the earthquakes that hit the Ionian Islands were gathered in an effort to evaluate them and to find possible correlations with the other types of maps. Based on the correlation results, the consideration of the Vs30 parameter in the Greek antiseismic code is proposed for a better categorization of the geological formations.

The present study aims to present the results of a near-surface geophysical investigation carried out ata construction site in the area of Goudi (Athens) along with its contribution to the determination of thegeotechnical characteristics. For this purpose, the Ground Penetrating Radar (GPR), ElectricalResistivity Tomography (ERT), Seismic Refraction Tomography (SRT) and Multichannel Analysis ofSurface Waves (MASW) techniques were implemented in the area. The cores of three geotechnicalboreholes existing in the area have also been taken into account. The application of the GPR and ERTtechniques did not reached a satisfactory investigation depth, however the existence of a possiblemechanically degraded zone have been adumbrated at the south part of the excavation area. Throughthe application of the SRT and MASW techniques, the seismic waves velocities of the investigatedlithological formations were calculated and the subsurface structure of the study area was outlined.Additionally, lateral variations in the P-wave seismic velocities, especially in the first investigatedseismic layer, provided further evidence for the existence of mechanically unstable zones, whichnecessitate a more detailed investigation. Finally, from the laboratory determination of the formations’densities and their seismic wave velocities, their elastic moduli and geotechnical parameters have beencalculated.

Light Detection And Range (LiDAR) data have been used in numerous case studies, related to fast-developing landslides and rockfalls, producing remarkably precise Digital Terrain Models (DTMs). When these models are coupled to classic near-surface geophysical methods, they result in the high-accuracy mapping of the open surface and subsurface morphology, an essential element for a modern coastal management study. In this work, we introduce the diachronic monitoring and detection of alterations on the surface of the active fault of Psatha (Greece), via a multiple-phase study within a period of 11 years, by using terrestrial LiDAR scans and Electrical Resistivity Tomography (ERT).The successful combination of these techniques is being used to reveal and quantify the landscape evolution involving the surface alterations at the fault adjacent coastal zone, the sea intrusion, and even the coastline displacement, in any coastal area characterized by similar features.

The cave of Alistrati, is located in the Prefecture of Serres, Northern Greece near the foothills ofMount Menoikio, in the area of Petroto. This area is structured by crystalline limestones, where thedevelopment of a complex and multilevel karst system is favored. An extensive geomorphologicalsurvey was carried out for the accurate mapping of the karst surface above the cave, using UAS. Forthe investigation of a possible lateral extension of the existing karstic conduit, a detailed surfacegeophysical investigation was carried out. More specifically, three geophysical techniques wereimplemented: a) the Electrical Resistivity Tomography (ERT), b) the Ground Penetrating Radar(GPR) technique and c) the Very-Low Frequency (VLF) method. These 13 lines of the threegeophysical techniques are fully matched at 4 locations and were join-interpreted, yielding remarkablefindings. The comparative results of the above geophysical techniques, as well as their 3Dpresentation, highlight similar geophysical anomalies, evaluated as different types of karst systemstructures. Therefore, the combined geophysical survey has indicated the existence andinterconnection of the first two karst levels of the area, up to a depth of 50m, as well as the possibleextension of the Alistrati karstic conduit to the northeast.

The coastal environment of central Kyparissiakos Gulf, located at the west coast of Peloponnesus, Greece, comprises of a sandy beach associated with an extended dune field at its backshore area. This area is characterized as an essentially tideless coastal environment exposed to high wave activity. Regarding the identification, the thickness and characteristics of the uppermost substratum of the selected coastal site a detailed geophysical research was carried out. The geophysical survey aims to determine the thickness and the characteristics of the upper substratum of the selected coastal area, leading to the quantification of the sediment budget; the latter is considered essential to address potential coastal erosion. For this reason, the geophysical techniques of Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) were implemented to profiles normal and parallel to the shoreline. The geophysical results reveal the presence of the interface between the dry and wet sand deposits, along with the structure and the downward extension of the sandy material.

Greece is a country structured by land, several islands and sea. A regional gravity model of such a country demands the involvement of several types of gravity data in order to cover all its territory. In this paper, we present the development of a regional combined gravity model of Greece and its surroundingarea, by integrating terrestrial, marine (shipborne and altimetry-derived gravity data) and satellite data (GOCE and GRACE data). These kinds of data, especially the terrestrial and marine ones, have passed quality and validation control since they were collected from different organizations, which means that they probably have been acquired and processed with different parametersand formulas. Following that, their integration was accomplished with the application of the least-squares collocation (LSC). Therefore, a newly combined regional gravity model of Greece and its surrounding areas has been developed. This gravity model can be valuable for regional geological and geophysical studies of Greece, since it provides homogeneously the distribution of Complete Bouguer anomaly (CBA) all over Greece, with updated gravity data and in good agreement with the initial gravity datasets that have been used.