NW Peloponnese Research Articles

Designers of Nature's Subterranean Abodes: Insights into the Architecture and Utilization of Burrow Systems of Thomas' Pine Vole, Microtus thomasi (Rodentia: Arvicolinae).

Microtus thomasi (Rodentia: Arvicolinae), a fossorial vole endemic to the SW Balkans, uses a variety of substrates but its underground behavior remains poorly understood. This study examines the architecture and utilization of M. thomasi burrow systems in NW Peloponnese, Greece. In particular, eight burrow systems were meticulously excavated and studied, with comprehensive measurements taken of key characteristics, including length, depth, soil mounds, and surface openings. Key coordinates were recorded using a differential GPS device for detailed mapping and fractal dimension analysis using the box-counting method was employed to assess burrow system complexity. Soil samples were analyzed for particle size and chemical composition, and vegetation types at each site were identified. We did not find statistically significant correlations between size and complexity of the burrow systems and soil composition, altitude, or specific soil components. On the other hand, we did observe statistically significant differences in tunnel diameter between two burrow systems and in tunnel depth between more. Moreover, our study showed that more than one same-sex individual can occupy a single burrow system and not just an adult male-female pair, that was previously recorded, indicating the need for further study of the social behavior of this vole species. This study provides valuable insights into the underground behavior of M. thomasi by providing information on the features of its burrow systems, thus contributing to our understanding of its biology.

Tectonic Loading and Overthrust Gliding of the Pindos Nappe (NW Peloponnese): Insights from Thermochronology

Tectonic Loading and Overthrust Gliding of the Pindos Nappe (NW Peloponnese): Insights from Thermochronology

A Reappraisal of the Destructive Earthquake (Mw5.9) of 15 July 1909 in Western Greece

Studies on earthquakes that occurred in the early instrumental period of seismology are of importance for the seismic hazard assessment and are still under investigation since new data are being increasingly revealed. We study the case of a moderate-to-strong earthquake that occurred on 15 July 1909 in NW Peloponnese, Greece. Although the earthquake event was quite destructive, it remains little-known so far in the seismological tradition. We compiled a variety of documentary sources and showed that the earthquake caused extensive building destruction in Chavari and in many other villages with an estimated maximum intensity IX (in EMS-98 scale) and a death toll as high as 55. We also assigned macroseismic intensities in several observation points and drew isoseismal lines by applying the nearest-neighbor technique. From empirical relationships between magnitude and intensities, we estimated the macroseismic magnitude of proxy Ms5.9. Our examination also revealed a variety of earthquake associated phenomena including several types of precursors and abundant co-seismic hydrological changes and ground failures, such as soil liquefaction, surface ruptures, and rock falls. Since no surface fault-trace was reported, the determination of the causative blind fault remains an open issue for future investigation.

Contributions to the bulb flora of Ilias (NW Peloponnese, Greece): Iridaceae

Contributions to the bulb flora of Ilias (NW Peloponnese, Greece): Iridaceae

Contributions to the bulb flora of Ilias (NW Peloponnese, Greece): Liliaceae

Contributions to the bulb flora of Ilias (NW Peloponnese, Greece): Liliaceae

Estimating total sediment transport in a small, mountainous Mediterranean river: The case of Vouraikos River, NW Peloponnese, Greece

Estimating total sediment transport in a small, mountainous Mediterranean river: The case of Vouraikos River, NW Peloponnese, Greece

Thermotectonic constraints on the geodynamic evolution of the Pindos fold‐and‐thrust‐belt by low‐temperature (U–Th)/He thermochronometry

This study presents new thermochronometric data to constrain the cooling history of the Pindos fold‐and‐thrust‐belt (PFTB) on the NW Peloponnese, and the timing of nappe stacking in the external Hellenides in western Greece. Low‐temperature thermochronology was performed on apatite and zircon minerals extracted from basal exposures of the PFBT in Mt. Erymanthos (NW Peloponnese) using the (U‐Th)/He system. Three bedrock samples collected from a profile across the strike of the PFBT returned thermochronometric ages for the apatite (AHe) between 15 and 9 Ma, while for the zircon (ZHe) the ages are interpreted as unreset (or partially reset). The AHe ages are interpreted as cooling ages related to the Cenozoic geodynamic evolution of the PFTB. Thermal models generated in this research demonstrate two phases of geodynamic evolution of the PFBT during the Cenozoic: an early one associated with the heating of the fold‐and‐thrust belt during 40–20 Ma and a later one associated with fast cooling from 20 Ma onwards. Heating is attributed to the structural thickening of the PFTB while cooling is associated with enhanced uplift and exhumation, which became widespread in Erymanthos by 9 Ma. The initiation of cooling on Mt. Erymanthos echoes the substantial geometric remodelling that underwent the Hellenic arc during the Middle Miocene, associated with slab rollback and arc extension, and is connected to the underplating of the internal segments of the external platform (Gavrovo‐Tripolis unit) by the external metamorphic segments (Mani and Arna units). The current inverse thermal modelling offers the first continuous description of the geodynamic evolution of the most prominent fold‐and‐thrust belt of the Hellenides, from the oceanic stage through basin inversion to uplift and orogen decay.

The 25 October 2018 Zakynthos (Greece) earthquake: seismic activity at the transition between a transform fault and a subduction zone

SUMMARYThe properties of the Mw = 6.7 earthquake that took place on 25 October 2018, 22:54:51 UTC, ∼50 km SW of the Zakynthos Island, Greece, are thoroughly examined. The main rupture occurred on a dextral strike-slip, low-angle, east-dipping fault at a depth of 12 km, as determined by teleseismic waveform modelling. Over 4000 aftershocks were manually analysed for a period of 158 d. The events were initially located with an optimal 1D velocity model and then relocated with the double-difference method to reveal details of their spatial distribution. The latter spreads in an area spanning 80 km NNW–SSE and ∼55 km WSW–ENE. Certain parts of the aftershock zone present strong spatial clustering, mainly to the north, close to Zakynthos Island, and at the southernmost edge of the sequence. Focal mechanisms were determined for 61 significant aftershocks using regional waveform modelling. The results revealed characteristics similar to the main shock, with few aftershocks exhibiting strike-slip faulting at steeper dip angles, possibly related to splay faults on the accretionary prism. The slip vectors that correspond to the east-dipping planes are compatible with the long-term plate convergence and with the direction of coseismic displacement on the Zakynthos Island. Fault-plane solutions in the broader study area were inverted for the determination of the regional stress-field. The results revealed a nearly horizontal, SW–NE to E–W-trending S1 and a more variable S3 axis, favouring transpressional tectonics. Spatial clusters at the northern and southern ends of the aftershock zone coincide with the SW extension of subvertical along-dip faults of the segmented subducting slab. The main shock occurred in an area where strike-slip tectonics, related to the Cephalonia Transform Fault and the NW Peloponnese region, gradually converts into reverse faulting at the western edge of the Hellenic subduction. Plausible scenarios for the 2018 Zakynthos earthquake sequence include a rupture on the subduction interface, provided the slab is tilted eastwards in that area, or the reactivation of an older east-dipping thrust as a low-angle strike-slip fault that contributes to strain partitioning.

Deep structure of the Hellenic lithosphere from teleseismic Rayleigh-wave tomography

SUMMARYThis research provides new constraints on the intermediate depth upper-mantle structure of the Hellenic lithosphere using a three-step Rayleigh-wave tomography. Broadband waveforms of about 1000 teleseismic events, recorded by ∼200 permanent broad-band stations between 2010 and 2018 were acquired and processed. Through a multichannel cross-correlation technique, the fundamental mode Rayleigh-wave phase-velocity dispersion curves in the period range 30–90 s were derived. The phase-velocities were inverted and a 3-D shear velocity model was obtained down to the depth of 140 km. The applied method has provided 3-D constraints on large-scale characteristics of the lithosphere and the upper mantle of the Hellenic region. Highlighted resolved features include the continental and oceanic subducting slabs in the region, the result of convergence between Adria and Africa plates with the Aegean. The boundary between the oceanic and continental subduction is suggested to exist along a trench-perpendicular line that connects NW Peloponnese with N. Euboea, bridging the Hellenic Trench with the North Aegean Trough. No clear evidence for trench-perpendicular vertical slab tearing was resolved along the western part of Hellenic Subduction Zone; however, subcrustal seismicity observed along the inferred continental–oceanic subduction boundary indicates that such an implication should not be excluded. The 3-D shear velocity model supports an N–S vertical slab tear beneath SW Anatolia that justifies deepening, increase of dip and change of dip direction of the Wadati-Benioff Zone. Low velocities found at depths <50 km beneath the island and the backarc, interrelated with recent/remnant volcanism in the Aegean and W. Anatolia, are explained by convection from a shallow asthenosphere.

Detection of active fault scarps in western Peloponnese, Greece

This study aims at reconstructing Pleistocene slope erosion processes and transformation of relief in well-developed Pleistocene (Tyrrhenian) marine terraces along the western Peloponnese. The investigations are based on existing geological data, field observations, a selected seismic reflection profile, sedimentological analysis and radiometric dating.Aftershock rupture segment extends for 6 km in a WNW direction. Each fault movement in an earthquake results in a sudden increase in the size of the scarp, by an amount ranging from a few centimeters to several meters.Thrust faulting occurs on shallow dipping faults and does not commonly produce a true fault scarp, because the tip of the upper part, over the thrust block, tends to collapse, leaving a sinuous scarp that does not coincide with the fault plane. Strike-slip faulting may result in a scarp if there is a significant extensional or thrust component of motion, or if rock-types with different weathering characteristics and thickness are compared by faulting. Failing this, both active and inactive faults are often marked by a fault-line, a line of preferential erosion along the fault. The combined effects of fault motion, erosion, and sediment deposition affect the form of the scarp and the latter two will eventually eliminate it after movement on the fault ceases. If the rock erosion rates on both fault sides are known or can be assumed to be negligible, and the sediments deposited contain material that can be dated, then the magnitude of the scarp can be used to determine the age at which the scarp began to form and the long-term rate of movement on the fault. More information regarding the relative significance and rate of movement of these faults can be obtained by observing their effects on the drainage pattern in the area.In particular, morphotectonic data indicate that the observed rupture segment may reflect a fault-line scarp corresponding to an old fault scarp, which belongs to the isotopic stage 7 or prior, i.e. isotopic stage 11, during the evolution of NW Peloponnese basin.Moreover, morphotectonic data clearly shows that NW Peloponnese is characterized by a complex structural pattern and erosion process phenomena aided by human activity. This data is well-supported by seismic reflection profiles information.

Ground deformation and associated hazards in NW peloponnese (Greece)

ABSTRACTIn the last decades, ground deformations were investigated, analysed and monitored using several methods. As a consequence of a spreading urbanization, several phenomena, e.g. landslide and subsidence, were emphasized or triggered causing not only socio-economic damages, but, in some cases, also casualties. The investigation and mapping of these phenomena are important for both local authorities and civil protection in order to promote a higher conscientious urban planning and to highlight the more hazardous areas. Furthermore, the information are a key point for social development connected to the awareness of the environment and the related risk. The Achaia prefecture, in the north-eastern Peloponnese (Greece), close to the Gulf of Patras, is an area strongly affected by subsidence and landslides. Furthermore, this is an earthquake-prone area, a factor that can trigger some mass movements. For this region, a landslide inventory was realized with the help of the interpretation of Persistent Scatterers data, for the period 1992–2008, and high-resolution optical satellite images, available until 2016, in addition to the investigation of the landslide State of Activity. Moreover, for the coastal area, a section was investigated to evidence subsidence.

Preliminary Data of Fluvial Geomorphological Evolution and Its Link with Hazards and Human Impact: The Case of Peiros River, North Western Peloponnese, Greece

River channel dynamics are the result of the complex interaction between natural and human factors, at both local and regional scale. The study of river channel dynamics may be an important way to better understand the mechanisms that rule the functioning of fluvial systems, allowing predictions of its future evolution to be made and appropriate adaptation measures to be taken, remediating the risks related to the fluvial dynamics. The purpose of this study is to present specific aspects concerning the river channel dynamics of Peiros River, NW Peloponnese, Greece and to reveal the role of various control factors. Peiros, the longest river in Achaea, has sources at the NE part of the Erymanthos mountains flowing into Patras gulf. This study traces the various stages of geomorphological evolution of the low part of Peiros's river channel and enables us to study the links between human activity, local tectonics, morphology and fluvial dynamics. The study area belongs to the geotectonic zone of Gavrovo-Tripoli flysch, consisting mainly of medium-bedded fine-grained sandstones and mudstones and influenced by ENE and WNW trending faults aligned with the river flow. The spatial and temporal variability of sediment transport is controlled by various variables, including the natural features of the catchments and human activity. The latter is an important control factor for both the processes of sediment generation, transfer and accumulation and for channel dynamics. At the same time, these processes are responsible on short and long run for the alteration of the river channels, which entail negative environmental consequences. The study revealed restriction of sediment supply, coastal retreat, lateral erosion and migration of the rivers channel that complies with the local tectonics of the area, although major stream offsets are not created. The morphological changes although, are mainly attributed to human intervention factors, such as the construction of a dam and transversal bars that restricted the water flow and consequently the sediment supply. That factor combined with the climate change, had as result to drastically alter the morphology of the area. These morphological changes, except of loss of property and boundary problems, also made the area vulnerable to flush flood events. Structures close to the coast are exposed to more risk because of the measured coast retreat. No remediation measures have been taken, except the installation of rip-rap of limited length and one groin, in an attempt to slow down the coastal retreat and diminish wave action.

Thrust tectonics in the central part of the External Hellenides, the case of the Gavrovo thrust

Thrust faulting plays an important role in the structural deformation of Gavrovo and Ionian zones in the central part of the ‘External Hellenides’ fold-and-thrust belt. The Skolis mountain in NW Peloponnese as well as the Varassova and Klokova mountains in Etoloakarnania are representative cases of ramp anticlines associated with the Gavrovo thrust. Surface geology, stratigraphic data and interpretation of seismic profiles indicate that it is a crustal-scale thrust acted throughout the Oligocene time. It is characterized by a ramp-flat geometry and significant displacement (greater than 10 km). Out of sequence thrust segmentation is inferred in south Etoloakarnania area. Down flexure and extensional faulting in the Ionian zone facilitated the thrust propagation to the west. The thrust emplacement triggered halokenetic movement of the Triassic evaporites in the Ionian zone as well as diapirisms that were developed in a later stage in the vicinity of the Skolis mountain.

Hazard due to earthquake-induced rock falls: The use of remote sensing data and field mapping in the case of Skolis Mountain, NW Peloponnese

Inventory of pre-earthquake and earthquake triggered landslides is used to provide insight of the tectonic forcing in the development of the rock slopes of the Skolis Mountain, in the North Peloponnese. For the purposes of inventory of landslides we analyzed © Google Earth photographs based on drawing polygons and paths in order to create ‘Keyhole Markup Language’ or KML files. © Google Earth photographs analysis and surface mapping indicate that the Skolis Mountain is affected by long- term climatically and tectonically controlled rock falls and minor rock slides. The rock falls show a progressive inflation in surface area from 2007 to 2009. The post-earthquake surface area of the rock falls increased three times. In addition, there was a series of rock falls descending Skoli’s slopes by free fall, bouncing, or rolling causing damages in the Santomerion village and blocking significant part of the dirt roads around it. These boulders are clustered in three areas across the western bluff of the mountain.

Earthquake clusters in NW Peloponnese.

Clusters commonly occur as main shock – aftershock (MS-AS) sequences but also as earthquake swarms, which are empirically defined as an increase in seismicity rate above the background rate without a clear main shock. A delcustering algorithm is employed to identify clusters from a complete catalog of earthquakes that occurred in the area of NW Peloponnese (Greece) during 1980-2007. In order to distinguish these clusters we calculate the skewness and kurtosis of seismic moment release for each cluster, since swarm-like sequences generally have lower skew value of moment release history than MS-AS. The spatial distribution of b-value was calculated for the entire catalog as for the declustered one, in order to correlate them with seismicity behavior of the region. Finally, the pre-stress field of Achaia 2008 earthquake was calculated aiming to associate the stress accumulation with the occurrence of the identified clusters

Study of the tornado event in Greece on March 25, 2009: Synoptic analysis and numerical modeling using modified topography

Recent research revealed that western Greece and NW Peloponnese are regions that favor prefrontal tornadic incidence. On March 25, 2009 a tornado developed approximately at 10:30 UTC near Varda village (NW Peloponnese). Tornado intensity was T4–T5 (TORRO scale) and consequently caused an economic impact of 350,000 € over the local society. The goals of this study are: (i) to analyze synoptic and remote sensing features regarding the tornado event over NW Peloponnese and (ii) to investigate the role of topography in tornadogenesis triggered under strong synoptic scale forcing over that area.Synoptic analysis was based on the European Centre for Medium-Range Weather Forecasts (ECMWF) data sets. The analysis of daily anomaly of synoptic conditions with respect to 30 years' climatology (1981–2010), was based on the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis data sets. In addition, numerous remote sensing data sets were derived by the Hellenic National Meteorological Service (HNMS) weather station network in order to better interpret the examined tornado event.Finally, numerical modeling was performed using the non-hydrostatic Weather Research and Forecasting model (WRF), initialized by ECMWF gridded analyses, with telescoping nested grids that allow the representation of atmospheric circulations ranging from the synoptic scale down to the meso-scale. The two numerical experiments were performed on the basis of: (a) the presence and (b) the absence of topography (landscape), so as to determine whether the occurrence of a tornado – identified by diagnostic instability indices – could be indicated by modifying topography.The energy helicity index (EHI), the bulk Richardson number (BRN) shear, the storm-relative environmental helicity (SRH), and the maximum convective available potential energy (MCAPE, for parcels with maximum θe) were considered as principal diagnostic instability variables and employed in both numerical experiments. Furthermore, model verification was conducted, accompanied by analysis of the absolute vorticity budget.Synoptic analysis revealed that the synoptic weather conditions on March 25, 2009 are in agreement with the composite synoptic climatology for tornado days over western Greece. In addition, maximum daily anomalies at the barometric levels of 500, 700, 850 and 925hPa were found, compared to the climatology of composite mean anomalies for tornado days over western Greece. Numerical simulations revealed that the topography of NW Peloponnese did not constitute an important factor during the tornado event on March 25, 2009, based on EHI, SRH, BRN, and MCAPE analyses.

Earthquake triggered rock falls and their role in the development of a rock slope: The case of Skolis Mountain, Greece

Inventory of pre-earthquake and earthquake triggered landslides is used to provide insight into the interplay between climatic and tectonic forcing in the development of the rock slopes of the Skolis Mountain, in the NW Peloponnese. Aerial photograph analysis and surface mapping indicate that the Skolis Mountain is characterized by long-term climatically and tectonically controlled rock falls forming taluses. Temporally these taluses show a slow progressive inflation in surface area from 1945 to 2007. However, the post-earthquake surface area of the rock falls increased three times. Similarly 75 rock fall sites before the earthquake, increased into 89 after the Movri Mountain earthquake (Mw 6.4). In addition, during the earthquake a series of isolated rock falls descended Skolis slopes causing threat of the Santomerion village and blocking significant part of the dirt roads around it. These boulders are clustered in three areas beyond the base of taluses. The rock slope failures are controlled by a complex array of discontinuities that are conveniently related to rock mass classification following the geological strength index. These discontinuities are associated with joints and faults caused during the formation of the Hellenides fold- and thrust-belt, and/or related tectonic damage. We infer that a dense pattern of fractures in limestone plays a crucial role in the reactivation of movement within the rock falls during the 2008 Movri Mountain earthquake. All these data are used to define two borders, the taluses base and the rock fall hazard border beyond the base of taluses. For defining these borders we use the angle β drawn from the boulders' release zone down its maximal runout points. Our results indicate that the border defined by the β=33° corresponds to the climatically driven rock falls while the β=24° border is defined as the boulders' maximum runout during earthquakes.

Synergy of tectonic geomorphology, applied geophysics and remote sensing techniques reveals new data for active extensional tectonism in NW Peloponnese (Greece)

In tectonically active areas, such as in the northwest Peloponnese of western Greece, geomorphic processes are strongly influenced by active faulting; in many cases such faults cannot be easily identified. In this paper we apply multidisciplinary analysis (morphotectonic indices, neotectonic mapping, geophysical surveys and remote sensing techniques) to map the recently-recognized east–west trending Pineios River normal fault zone with a high degree of accuracy, and to better understand its contribution to the evolution of the ancient region of Elis during Holocene time. Fault activity seems to be related to frequent changes in river flow patterns and to displacements of the nearby shoreline. We argue that fault activity is the main reason for migration of Pineios river mouth as documented for several time periods during historical time. Quantitative constraints on deformation caused by the faulting were applied through the application of the morphotectonic indices proposed in this paper, including drainage network asymmetry and sinuosity, and mountain front sinuosity, all of which indicate that this is a highly active structure. Slip rates calculated to be as high as 0.48mm/yr for the last 209ka (based on previously published dating) were verified by applied geophysical methods. The fault surface discontinuity was identified at depth using vertical electrical resistivity measurements and depositional layers of different resistivity were found to be clearly offset. Displacement increases toward the west, reaching an observed maximum of 110m. The most spectacular landform alteration due to surface deformation is the north–south migration of the river estuary into completely different open sea areas during the late Quaternary, mainly during the Holocene. The sediment transport path has been altered several times due to these changes in river geometry with and the most recent seeming to have occurred almost 2000years ago. The river estuary migrated to its contemporary position along the southern coast, settled on the hanging wall, inducing retrograding of the northern coast, and settled on the foot wall, with rates reaching the order of 0.52m/yr, as concluded from historical and recently-acquired remote sensing data.

Seismic intensity assignments for the 2008 Andravida (NW Peloponnese, Greece) strike-slip event (June 8, Mw=6.4) based on the application of the Environmental Seismic Intensity scale (ESI 2007) and the European Macroseismic scale (EMS-98)

On June 8, 2008, a strike-slip earthquake (Mw=6.4) was generated NE of the Andravida town (NW Peloponnese, western Greece) due to the activation of the previously unknown western Achaia strike-slip fault zone (WAFZ). Extensive structural damage and earthquake environmental effects (EEE) were induced in the NW Peloponnese, offering the opportunity to test and compare the ESI 2007 and the EMS-98 intensity scales in a moderate strike-slip event. No primary EEE were induced, while secondary EEE including seismic fractures, liquefaction phenomena, slope movements and hydrological anomalies were widely observed covering an area of about 800 km<sup>2</sup>. The lack of primary effects and the relatively small surface deformation with respect to the earthquake magnitude is due to the thick Gavrovo flysch layer in the affected area that isolated and absorbed the subsurface deformation from the surface. According to the application of the EMS-98 scale, damage to masonry buildings ranged from grade 3 to 5, while damage in most of R/C buildings ranged from grade 1 to 3. A maximum ESI 2007 intensity VIII-IX is recorded, while the maximum EMS-98 intensity is IX. For all the sites where intensity VIII has been recorded the ESI 2007 and the EMS-98 agree, but for others the ESI 2007 intensities values are lower by one or two degrees than the corresponding EMS-98 ones, as it is clearly concluded from the comparison of the produced isoseismals. An exception to this rule is the Valmi village, where considerable structural damage occurs (IX<sub>EMS-98</sub>) along with the lack of significant EEE (V<sub>ESI 2007</sub>). This variability between the ESI 2007 and the EMS-98 intensity values is predominantly attributed to the vulnerability of old masonry buildings constructed with no seismic resistance design. Correlation of all existing data shows that the geological structure, the active tectonics, and the geotechnical characteristics of the alpine and post-alpine formations along with the construction type of buildings were of decisive importance in the damage and the EEE distribution.

The Nisi Fault as a key structure for understanding the active deformation of the NW Peloponnese, Greece

The previously unknown Nisi Fault in NW Peloponnese was ruptured during the 2008 Movri Mountain earthquake attaining a maximum offset of 25cm. The fault is interpreted as a branch of a flower structure above a blind strike-slip fault. We investigate the Nisi Fault seismotectonic evolution using morphotectonic analysis in order to determine whether the landscape is affected by tectonic forcing and paleoseismology to determine earthquake recurrence interval and fault slip rates. We applied several geomorphic indices, such as the asymmetry factor (AF), the stream length–gradient index (SL), the valley floor width to valley height ratio (Vf), the mountain-front sinuosity (Smf), the drainage basin shape (Bs) and the hypsometric curve (Hc), in four large drainage basins of the study area. The results show that fault-related vertical motions and the associated tilting influenced the drainage geometry and the landscape development. Values of stream-gradient indices (SL) are relatively high close to the fault trace. Mountain-front sinuosity (Smf) mean values along the fault zones range from 1.12 to 1.23. Valley floor width to valley height ratios (Vf) mean values along the studied fault range between 0.21 and 2.50. Drainage basin shape (BS) mean values along the fault range from 1.04 to 3.72. Lateral fault growth was likely achieved by propagation primarily towards north-northwestward. The paleoseismic history of the fault, investigated by a trench and 14C dating of seven samples, indicates two morphogenic earthquakes in the last 1kyr. Therefore, we suggest that the Nisi Fault displays a slip rate on the order of 1mm/yr and a recurrence interval ranging between 300 and 600years. From a seismotectonic point of view, the fault is classified as high activity rate, with abundant but discontinuous geomorphic evidence of its activity. Other similar faults affecting the western Peloponnese can be envisaged with a similar procedure. Additionally, the seismic history and surface expression of the Nisi Fault, resembles other faults of similar length in Greece and Italy. Particularly, a crucial issue in terms of seismic risk management is that neotectonic analysis has to be envisaged carefully on short in length faults, since these faults can be possibly related to strong earthquakes.