Search Results (26)

Chelmos Vouraikos UNESCO Global Geopark is located in North Peloponnesus, Greece. As a member of the Global Geoparks Network, it is valued for its rich geoheritage in combination with its natural and cultural wealth. Several different landforms of international value are located in the area. The scope of this work is to present an overview of its geomorphological features, link them with biodiversity and highlight their value for geotourism. Its geology is complicated due to intense tectonism. Three geotectonic units of the Alpine Orogeny can be found along with post-Alpine sediments related to the Corinth Gulf rifting. The area is highly covered by limestone creating important karst landforms. High peaks surround river valleys and deep gorges create breathtaking landscapes. Some of them cut through high and steep conglomerate slopes. Remnants of past glaciation have been preserved on Mt Chelmos. The exceptional geodiversity of the area is linked with rich vegetation and high endemism. The many identified geomorphological sites highlight the Geopark’s strong commitment to geomorphology and its importance as a key geomorphological destination. Highly visible geomorphological sites with ecological value can also promote environmental awareness and contribute to the protection of biodiversity. Full article

In our study we investigated the hydrodynamic circulation of the Gulfs of Patras and Corinth through modelling. To this end, ROMS was used to numerically calculate the parameters of the waters for these peculiar semi-enclosed basins. Several oceanographic forcings were used with an emphasis on the tides and the winds. With several simulations, each focusing on a specific element, we were able to describe more accurately the dynamics under the surface to complete what was previously done. The high velocity currents (0.6 m/s at the Patraic end of the strait) were validated through ADCP and satellite data, proving that modelling can be trusted to fill the gap in the in situ data over these two gulfs. Our simulations, mainly based on the month of May 2023, allowed us to understand the importance of the tides, especially in the Rio–Antirio Strait. There, the bottom currents are the strongest while the center of the Corinthian Gulf remains quiet. The surface dynamics were observed to be sensitive to the tides, the winds and the season, but general patterns were still highlighted for the oceanographic circulation of the gulfs. Full article

Geoarchaeological work and excavations of the Helike Project over the last 30 years in the Helike coastal plain, Gulf of Corinth, have yielded abundant evidence on ancient settlements, as well as the surrounding landscape and environmental changes that resulted from geological phenomena and catastrophic events. The research methods applied by the Helike Project followed a multidisciplinary approach, including combined archaeological excavations and palaeoseismological trenching, geophysical prospection, archaeometric, environmental, and soil micromorphology analyses, and computer-based landscape modelling. A wealth of settlement remains that were unearthed across the plain, ranging in date from the Early Helladic period (3rd millennium BC) to the Late Antiquity (5th century AD), indicates that the ancient inhabitants of the area chose to always resettle in the area by adjusting their ways of living to the geomorphology and natural hazards, prevailing each time. Our results show that disasters in the area increased between the Geometric and Roman times due to severe earthquakes that occurred approximately every 300 years. In particular, archaeological and geological finds recovered from the Late Classical–Hellenistic Helike settlement, which was revived in the western part of the plain shortly after the disastrous 373 BC earthquake, have enriched our knowledge regarding the historical seismicity of the region and past human–environment relationships. Full article

In the absence of in situ data, remote sensing becomes one of the most effective methods for analyzing the hydrodynamics of a basin. In the Gulf of Corinth, the lack of in situ information was addressed using 14 years of satellite data from the Copernicus database to investigate the water circulation dynamics of the Gulfs of Patras and Corinth. The combination of satellite observations and Data Interpolating Empirical Orthogonal Function (DINEOF) methods produced comprehensive maps detailing the hydrodynamic patterns in both gulfs. Despite the paucity of some parts of the datasets, the remaining data revealed key hydrodynamic features through their observations. From the western Patras Gulf to the eastern Corinth Gulf, gyres were the dominant features. The Patras Gulf is primarily characterized by a cyclonic gyre, while the Rio–Antirio Strait, which connects the two gulfs, exhibits unique dynamics due to internal wave activity and upwelling events. Currents generated near the strait flow toward the Corinth Gulf, where they are mostly trapped in an anticyclonic gyre near Itea Bay and a cyclonic gyre near Antikyra Bay. Our analysis highlights the unique dynamics of enclosed gulfs connected to the open sea via a strait. In this case, the Corinth Gulf acts as a smaller-scale analog to the Mediterranean Sea, offering insights into similar hydrodynamic behaviors. The updated hydrodynamic data also improve our understanding of sediment transport pathways and the chlorophyll distribution under present and past conditions. Full article

In this paper, the barotropic circulation in the gulfs of the Patras and Corinth system in Greece is numerically studied. This semi-enclosed hydrodynamic system is simulated as a unified basin, based on 3D simulations using the MIKE 3 Flow Model FM (HD). The wind and tide-induced flow, as well as their combined action, were examined in the whole basin of the system. Based on the numerically predicted results, salient features of the flow were highlighted, while different energetic zones concerning the hydrodynamic response of the system were specified. The tide propagation was studied in detail showing an increase in tidal amplitude up to 85% at the western entrance of the Gulf of Corinth. In addition, geophysical flow characteristics, surface eddies, and the current field as well as the vertical and horizontal structure of the flow in the gulfs’ system were calculated. Moreover, the effect of wind and tide on the exchange flowrate between the two gulfs and the response of the basin after a wind break were studied for typical wind speeds and directions. Full article

Human habitat is much controlled by the landscape and its ongoing processes overtime. Some of these processes occur instantaneously and are often triggered by seismic events with a major destructive impact on the human-built environment. Helike, on the southwest shore of the Gulf of Corinth, is a characteristic case of an ancient habitation site bearing witness to repetitious natural disasters from the Early Bronze Age to the Late Antiquity. The Late Classical-Hellenistic site, revived in the Helike plain after the 373 BC earthquake, has been systematically investigated thanks to the multidisciplinary research and excavations of the Helike Project in the last 35 years. This work has significantly enriched the historical seismicity of the region and shed light on past human-environment relationships. The study of the architectural remains excavated by the Helike Project, coupled with geological and soil micromorphological analysis on archaeological soils and sediments of the settlement, demonstrates a constant effort of the Helike people to reconcile with the elements of nature. Our results underline the destruction of a flourishing textile dyeworks operated at the settlement, due to a strong earthquake which triggered extensive morphological changes in a broader area. These changes include co-seismic liquefaction and lateral spreading, and post-seismic changes in the gradient of river channels. The former changes attest to an uplift in the headwater area and subsidence in the lowland plain of the ravine flowing near the ancient site. Full article

This study examines the body-wave velocity structure of Attica, Greece. The region is located between two major rifts, the Gulf of Corinth and the Euboekos Gulf, and has experienced significant earthquakes throughout history. The distribution of seismic activity in the area necessitates a thorough investigation of geophysical properties, such as seismic velocities, to reveal the extent of significant fault zones or the presence of potential hidden faults. This case study utilized over 3000 revised events to conduct a local earthquake tomography (LET). P- and S-wave travel-time data were analyzed to explore small- to medium-scale (~10 km) anomalies that could be linked to local neotectonic structures. The study presents a detailed 3-D seismic velocity structure for Attica and its adjacent regions. The results of the study revealed strong lateral body-wave velocity anomalies in the upper crust were related to activated faults and that a significant portion of the observed seismicity is concentrated near the sites of the 1999 and 2019 events. Full article

In the present work, the effects of wind- and tide-induced internal waves in the Rio-Antirio Strait in western Greece were studied by using three-dimensional numerical simulations. For the wind-induced flow in the strait, it emerged that the internal waves’ initiation is associated with the direction of the wind. Tidal action, with or without the combined action of wind, also generates internal waves in the strait, with amplitudes higher than 20 m. The action of the internal waves causes a subsurface inflow of colder waters from the Gulf of Corinth to the Gulf of Patras, as has been also simulated for the case of the wind-induced flow, generating strong hypolimnetic currents. The exchange flowrate between the Gulf of Patras and the Gulf of Corinth appeared to undergo significant modification for the wind-induced flow and had little effect for the pure tidal flow (in windless conditions) due to the development and action of the internal waves at the strait. The combined action of the tide and the wind was found to marginally affect the exchange flowrate between the two gulfs compared to the pure tidal flow. The interaction between the Coriolis effect and internal waves, at least away from the strait, forms a characteristic horizontal structure of flow. The structure of turbulence in the near strait area under the action of internal waves generated by the wind and/or tide was also discussed and compared with the corresponding barotropic flow. Full article

Remains of past sea levels such as tidal notches may provide valuable information for the investigation of relative sea-level changes (RSL) of eustatic/tectonic origin. In this review, we focus on case studies of coastal changes from the Corinth Gulf, where impacts of past earthquakes can be traced through various indicators. The southern coast has undergone a tectonic uplift during the Holocene, whereas the northern coast has undergone subsidence. The magnitude of RSL fall in the south Corinth Gulf is larger than RSL rise in the north. Exploiting previous measurements and datings, we created a geodatabase regarding the relative sea-level changes of the whole gulf, including geodetic data based on permanent GNSS observations. The combination of geomorphological (long-term) and geodetic (short-term) data is a key advance for this area, which is characterized by fast rates of N-S crustal extension and strong earthquakes. The joint dataset fits the tectonic model of an active half-graben where the hanging wall (northern coast) subsides and the footwall (southern coast) is uplifted. The highest uplift rates (3.5 mm/year) are near Aigion, which indicates an asymmetric localization of deformation inside this active rift. Full article

Ecosystem-based Blue Growth reflects the need to develop human activities taking place in the marine environment, under the scope of protecting marine ecosystems. To this end, the Marine Strategy Framework Directive identifies the specific ecological characteristics of a marine area, the human activities taking place in it and the main pressures induced thereof. The present work focuses on the semi-enclosed embayment of the Inner Ionian and adjacent gulfs (the Gulf of Corinth and the Gulf of Patras) in Western Greece, in order to present the type of environmental data and information required to be considered in the framework of ecosystem-based Blue Growth. Such data may include oceanographic and physical environmental features, biological and ecological distributions, areas of importance for species, communities, and habitats, along with spatial and temporal information regarding human activities and pressures caused. Data interpretation shows that future economic development in the study area should follow an ecosystem-based approach to maintain/achieve the Good Environmental Status and regulate existing and immerging anthropogenic activities within the framework of marine spatial planning. Full article

Probabilistic Seismic Hazard Assessment (PSHA) was carried out for the administrative region of Attica (Greece). Peak Ground Acceleration (PGA) and Peak Ground Velocity (PGV) values were calculated for return periods of 475 and 950 years for five sub-areas covering the entire region. PGA hazard curves and Uniform Hazard Spectra (UHS) in terms of spectral acceleration (S_a) values were generated for Athens, Methana, and the capitals of each island of Attica (Salamina, Aegina, Poros, Hydra, Spetses, Kythira, and Antikythira). Area sources were adopted from the Euro-Mediterranean Seismic Hazard Model 2013 (ESHM13) and its update, ESHM20, taking into account both crustal and slab tectonic environments. Ground Motion Prediction Equations (GMPEs) proposed for the Greek territory were ranked for PGA and PGV. Each GMPE was reconstructed as a weighted model, accounting for normal and non-normal focal mechanisms for each area source. PGA, PGV, and S_a values were computed using a logic tree, integrating the seismotectonic models as major branches and sub-logic trees, comprised of multiple ranked GMPEs for each area source, as minor branches. The results showed higher seismic hazard values in sub-areas near the Gulf of Corinth and the slab interface, which could indicate a need to revise the active building code in Attica. Full article

The Gulf of Corinth is a semi-isolated basin in central Greece interrupting the Pindus Mountain Range, which nowadays is a biodiversity hotspot. Considering its key location, deep drilling was carried out within the International Ocean Discovery Program (IODP; Expedition 381: Corinth Active Rift Development) aiming to improve our understanding of climatic and environmental evolution in the region. Here, we present a new long pollen record from a Mediterranean setting in the southernmost tip of the Balkan Peninsula recording the vegetation succession within the Quaternary. The Corinth pollen record shows no major shifts in arboreal pollen between glacial and interglacial intervals, while Mediterranean and mesophilous taxa remain abundant throughout the study interval. During interglacials, the most frequent reconstructed biomes are cool mixed evergreen needleleaf (CMIX) and deciduous broadleaf forests (DBWB), while graminoid with forb (GRAM) and xerophytic shrubs (XSHB) dominate within glacials. Our findings support the hypothesis that the study area was a significant refugium, providing suitable habitats for Mediterranean, mesophilous and montane trees during successive Quaternary climate cycles. Full article

The Corinth Rift, in Central Greece, is one of the most seismically active areas in Europe. In the eastern part of the Gulf of Corinth, which has been the site of numerous large and destructive earthquakes in both historic and modern times, a pronounced earthquake swarm occurred in 2020–2021 at the Perachora peninsula. Herein, we present an in-depth analysis of this sequence, employing a high-resolution relocated earthquake catalog, further enhanced by the application of a multi-channel template matching technique, producing additional detections of over 7600 events between January 2020 and June 2021. Single-station template matching enriches the original catalog thirty-fold, providing origin times and magnitudes for over 24,000 events. We explore the variable levels of spatial and temporal resolution in the catalogs of different completeness magnitudes and also of variable location uncertainties. We characterize the frequency–magnitude distributions using the Gutenberg–Richter scaling relation and discuss possible b-value temporal variations that appear during the swarm and their implications for the stress levels in the area. The evolution of the swarm is further analyzed through spatiotemporal clustering methods, while the temporal properties of multiplet families indicate that short-lived seismic bursts, associated with the swarm, dominate the catalogs. Multiplet families present clustering effects at all time scales, suggesting triggering by aseismic factors, such as fluid diffusion, rather than constant stress loading, in accordance with the spatiotemporal migration patterns of seismicity. Full article

Geomorphological and sedimentological indicators are often used to reconstruct not only coastal evolution, but also relative sea level changes. In this work, we studied the coastal sediments of Psatha bay (Alkyonides Gulf, Greece) and beachrock outcrops in order to reconstruct the coastal evolution of the area. The drillings analysis included stratigraphy, sediment texture and radiocarbon dating. Detailed mapping of the beachrocks was accomplished using DGPS-GNSS, as well as mineralogical analysis and OSL dating of beachrock samples. The new beachrock index points indicate a sea level that fell by 0.64 ± 0.13 m since 2200 ± 210 years BP and by 0.95 ± 0.13 m since 4160 ± 320 years BP, as a direct result of its location near the uplifting footwall of Psatha fault, suggesting further a rate of tectonic uplift of ~0.26 mm/yr for the late Holocene. Full article

The Gulf of Corinth (Central Greece) is one of the most rapidly extending rifts worldwide, with its western part being the most seismically active, hosting numerous strong (M ≥ 6.0) earthquakes that have caused significant damage. The main objective of this study was the evaluation of seismic hazard through a probabilistic and stochastic methodology. The implementation of three seismotectonic models in the form of area source zones via a logic tree framework revealed the expected level of peak ground acceleration and velocity for return periods of 475 and 950 years. Moreover, PGA values were obtained through the stochastic simulation of strong ground motion by adopting worst-case seismic scenarios of potential earthquake occurrences for known active faults in the area. Site-specific analysis of the most populated urban areas (Patras, Aigion, Nafpaktos) was performed by constructing uniform hazard spectra in terms of spectral acceleration. The relative contribution of each selected fault segment to the seismic hazard characterizing each site was evaluated through response spectra obtained for the adopted scenarios. Almost all parts of the study area were found to exceed the reference value proposed by the current Greek National Building Code; however, the three urban areas are covered by the Eurocode 8 regulations. Full article