Tectonic and Seismic Geomorphology


Tectonic and Seismic Geomorphology
Conveners: Efthimios Karymbalis, Marta Della Seta, Giandomenico Fubelli, James P. McCalpin, Maria Araújo, António Gomes
| Mon, 12 Sep, 14:30–16:30, 17:00–19:00|Room Sala Aeminium-C1A (b)
| Attendance Mon, 12 Sep, 16:30–16:45 | Display Mon, 12 Sep, 09:00–Tue, 13 Sep, 19:00|Poster area

Orals: Mon, 12 Sep | Room Sala Aeminium-C1A (b)

Chairpersons: Marta Della Seta, Efthimios Karymbalis, Maria Araújo
Giuseppe Corrado, Paola Di Leo, Dario Gioia, and Marcello Schiattarella

New geomorphological analyses of a wide coastal sector (ca. 1500 km2) between northern Calabria and Puglia (Lucanian segment), including a well exposed area of marine terraces along the Ionian coast of southern Italy, have been carried out. This belt represents a key area for investigating the middle-late Quaternary morphological and tectonic evolution of the orogenic system of southern Italy. The main goal of our research was the construction of a new, detailed and complete map of the entire sequence of marine terraces and associated paleoshorelines along the whole coastal sector. This was achieved following a systematic analysis of air‐photos and satellite images, integrated by field work and survey devoted to checking all the morphological features. Data were interpreted by uniform methods of geomorphological analysis in order to obtain an accurate reconstruction of the lateral continuity of the terraces and, therefore, to solve the problems of geometric and numerical fit between the terraces staircases from different sectors of the coastal belt separated by major rivers. A critical review of the literature related to geochronological data from the study area, integrated with a morphogenetic model based on the interaction between tectonic uplift and eustatic sea-level changes, allowed demonstrating that the different terraces are correlated to many highstand peaks, dating the highest/oldest terrace to mid-Pleistocene times. Such an approach allowed us to revise the wide data set related to the estimates of uplift rates based on the merely altitudinal criterion. Another relevant outcome of our study implies that the most external sectors of the orogenic chain (i.e. the southern Apennines), and likely the whole chain‐foredeep-foreland system, probably remained under a prevailingly compressional tectonic regime during the entire Quaternary period, with consequences for the seismic hazard of the region.

How to cite: Corrado, G., Di Leo, P., Gioia, D., and Schiattarella, M.: The marine terrace staircase of the Metaponto coastal belt, southern Italy: from geomorphological mapping to uplift rate estimates revised, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-340, https://doi.org/10.5194/icg2022-340, 2022.

Konstantinos Tsanakas, Julius Jara-Muñoz, Efthimios Karymbalis, Cengiz Yildirim, Kevin Pedoja, Dimitrios-Vasileios Batzakis, and Diamantina Griva

Offshore islands may furnish valuable information regarding deformation rates, their controlling mechanisms, and the dynamics of the upper crust in offshore areas along subduction zones, which otherwise would be difficult to quantify by direct observations. Here we study active deformation and faulting at glacial-cycle time scales in the Kythera Island, located in the southwestern part of the Hellenic subduction zone, between Crete and the Peloponnesus. The Kythera Island exposes an outstanding sequence of more than twelve levels of marine terraces that depict the active uplift of the island. These terraces are offset by several NNW-SSE and NNE-SSW-oriented active faults. We use high-resolution topography combined with morphometric analysis to map the marine terraces and to estimate the heave and throw rates of the main faults on the island. We divide the marine terrace sequence into two groups, the higher marine terraces (260 – 480 masl) comprising composite rasa surfaces, and the lower terraces (20 – 220 masl) characterized by staircase morphologies. We focus on the two main faults of the island, defined as F1 and F2, which display right- and left-lateral and dip-slip displacements, offsetting the marine terrace risers and treads. We link the activity of these faults with the occurrence of intermediate-depth and strong magnitude earthquakes such as the Mw 6.6 and 6.7 that occurred in the area of Kythera in 1903 and 2006, respectively.  Further dating of marine terrace surfaces and structural analysis will be carried out in the next months in order to correlate the marine terraces with Marine Isotope Stages and to estimate heave and throw rates of the faults. Our work emphasizes the importance of carrying observations in islands to elucidate the deformation rates in offshore areas of subduction zones.

How to cite: Tsanakas, K., Jara-Muñoz, J., Karymbalis, E., Yildirim, C., Pedoja, K., Batzakis, D.-V., and Griva, D.: Quantifying active faulting using marine terraces, Kythera Island, Greece, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-369, https://doi.org/10.5194/icg2022-369, 2022.

Ciro Cerrone, Alessandra Ascione, Gaetano Robustelli, Michele Soligo, and Paola Tuccimei

The Neogene to Quaternary southern Apennines mountain belt is flanked to the SW by the Tyrrhenian Sea back-arc basin, which was formed since late Miocene times. Extensional tectonics related to back-arc basin formation affected the Tyrrhenian margin of the southern Apennines since the Quaternary with formation of a series of horst and graben structures. Huge amounts of existing surface, subsurface and offshore data indicate that subsidence on the order of thousands of metres affected the grabens, and remarkable flights of marine terraces are indicative of Quaternary uplift of the horst blocks. The highest and older marine terraces, Early Pleistocene in age, occur up to several hundreds of metres above the sea level.

A huge number of former studies have provided fundamental data on both the outcropping (raised) and buried paleoshorelines and littoral deposits, the chronological framework for the identified relative sea level fluctuations mostly rests on local-scale relative chronology reconstructions constrained by dating that are still quite rare and sparse.

Detail-scale geomorphological-geological mapping, integrated with Quaternary stratigraphy, aimed at the recognition, characterisation and dating of raised marine terraces and paleoshorelines (tidal notches, platform inner edges) has been carried out in several key areas of the southern Apennines Tyrrhenian Sea margin, from Campania, in the North, to northern Calabria, in the South. The field surveys have been carried out both in rocky coasts (where continental deposits cover and sometimes hide the paleoshorelines) and in the two main alluvial-coastal basins, namely the Campania and Sele River plains. The new geochronological data constrain the ages of several late Middle Pleistocene to Late Pleistocene sea level markers, allowing a better definition of the vertical motions in each study area. Overall, the time-space distribution of the vertical motions on the regional scale is better reconstructed, along with the framework of the Quaternary surface uplift of the southwestern slope of the southern Apennines mountain belt.

How to cite: Cerrone, C., Ascione, A., Robustelli, G., Soligo, M., and Tuccimei, P.: Marine terraces in the Tyrrhenian Sea margin of the Southern Apennines (Italy): new constraints on differential vertical motions from dated paleoshorelines, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-540, https://doi.org/10.5194/icg2022-540, 2022.

Sanja Faivre, Tatjana Bakran-Petricioli, Marijan Herak, Jadranka Barešić, Davor Horvatić, and Damir Borković

The relative sea-level (RSL) change is a sum of effects of processes acting on local, regional and global scales. By far the most variable component of RSL change relates to local, non-linear scale processes, that is to active tectonics. The studied islands and islets, Lopud, Koločep and Grebeni are part of Dubrovnik archipelago, situated near the external front of the Dinarides where seismicity attains one of the highest levels in Croatia. The focal mechanisms in the area show that reverse and transpressive faulting prevails.

Studying the RSL markers: algal rims, tidal notches and Lithophaga lithophaga borehole upper limits, we identified one elevated palaeoshoreline at Lopud island (today 25-30 cm above the mean sea-level (MSL)) and two elevated palaeoshorelines at Koločep island and Grebeni islets (60-90 cm and 25-40 cm above MSL). The high-resolution geochronology built on radiocarbon dating of algal rims (77 sea-level index points) enabled the distinction of coseismic uplift events from subsidence periods during the last 3300 years. As a result, we provide new, field-based reconstruction of palaeoearthquakes, describe spatial patterns of differential uplift and distinguish the main drivers of RSL change.

Two major seismically triggered uplift events with displacements between 40 and 80 ± 15 cm per event have been differentiated along investigated sectors of the coast related to the Pelješac-Dubrovnik fault zone pointing to repeated earthquakes of magnitudes exceeding Mw = 6.5. The earlier, older events, caused larger displacements (60-80 cm) related to 4th to 6th century AD and 750-1100 AD earthquakes, while the later, younger events, revealed on average lower displacements (40-55 cm) corresponding to the 1520 AD quake and the 1667 Dubrovnik earthquake. The cumulative offsets increase from around 0.57 ± 0.15 m at Lopud to 1.00-1.25 ± 0.15 m at Koločep and Grebeni.

Interseismic periods allow further insight into regional and global driving mechanisms of RSL change. The distinction of local coseismic displacements of RSL history together with the previously obtained regional glacio- and hydro-isostatic adjustment estimates (between 0.30 and 0.34 mm/yr) allow us to approach the global contribution, which seems to be minimal between ~0 and 1800 cal AD as RSL changed at rates of 0.3 to 0.4 mm/yr. The increased rates of RSL change occurred prior to 0 cal AD, with rates of around 0.7 mm/yr, and go up to 1.4 mm/yr after 1800 cal AD.

Overall, here we demonstrate the importance of Lithophyllum rims in the studies of RSL change as they make creation of high-resolution geochronology possible. Moreover, this new approach refers to algal rims as a possible tool for constraining palaeoseismic events, allowing to supplement the database of instrumental records and historical observations through field-based evidence. This research was supported by Croatian Science Foundation project HRZZ-IP-2019-04-9445 – Relative sea-level change and climate change along the eastern Adriatic coast – SEALeveL.

How to cite: Faivre, S., Bakran-Petricioli, T., Herak, M., Barešić, J., Horvatić, D., and Borković, D.: Lithophyllum rims as markers of palaeoseismic events and relative sea-level change in the Dubrovnik archipelago, Southern Adriatic, Croatia, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-36, https://doi.org/10.5194/icg2022-36, 2022.

Cengiz Yildirim, Daniel Melnick, Okan Tüysüz, Cevza Damla Altınbaş, Julius Jara-Munoz, Konstantinos Tsanakas, Orkan Özcan, and Manfred Strecker

Cyprus is located right on the plate boundary where the African Plate subducts beneath the Anatolian Microplate. Although subduction zones are earthquake-prone areas, the seismicity of the Cyprus and adjacent areas are not very active during the instrumental period. Nevertheless, archaeological and historical data indicate casualties and destructions within the island because of strong tremors and tsunamigenic waves. None of these data gives information about the source faults of these earthquakes. Are they far-field earthquakes (e.g., AD 365 Crete) or near-field earthquakes that occurred nearshore of the island? We focused on the island’s coast and mapped geomorphological, sedimentological, biological, and archaeological strain markers to answer these questions. Our geomorphological observations reveal the presence of at least three major Holocene abrasion platform levels uplifted coseismically. The presence of biological markers such as reef rims provides a dateable material to quantify these events. We also observed archaeological fish tanks as evidence of coseismic uplift of the shoreline during the historical periods. Radiocarbon 14C dating results indicate a temporal clustering of earthquakes within the 1300-1700 yr BP, 2000-2200 yr BP, and 4500 yr BP, which indicate overlapping of 4th and 6th-century historical earthquakes and also older earthquakes beyond the historical records.

How to cite: Yildirim, C., Melnick, D., Tüysüz, O., Altınbaş, C. D., Jara-Munoz, J., Tsanakas, K., Özcan, O., and Strecker, M.: Earthquakes that Uplifted Cyprus in the last 4 ka, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-417, https://doi.org/10.5194/icg2022-417, 2022.

Francisco Gutiérrez, Mehdi Zarei, Hosein Deirnik, Maedeh Rahimi, and Alicia Medialdea

This work documents for the first time the prehistoric, but morphologically pristine, Emad Deh rock avalanche, located in the Fars Arc of the Zagros Mountains. The Zagros orogen is one of the most seismically active regions in the world. However, large earthquakes are very rarely accompanied by surface ruptures, restricting the possibility of integrating paleoseismic data in seismic hazard analyses. This limitation could be partially overcome by identifying and dating secondary paleoseismic evidence such as coseismic landslides. The source of the Emad Deh rock avalanche is located on a dip slope at the northern limb of the Gavbast anticlinal ridge. The slope, with a local relief of around 800 m, is essentially a hogback with a thick caprock of the competent Asmari Limestone, dipping around 35 degrees and underlain by marls with interbedded limestones of the Pabdeh Formation. The collapse of a bedrock slab around 2x2 km and its disintegration, resulted in the highly mobile Emad Deh rock avalanche, which accumulated on the unconfined piedmont an unstratified, unsorted and highly angular bouldery gravel deposit with an estimated minimum volume of around 220 million m3. The rock avalanche has a maximal height drop (H) of 914 m, a runout measured from the headscarp crown of 9280 m, and a H/L mobility index of 0.09. The cohesionless flow of fragmented rock formed a spatulate-shaped lobe around 32 km2 in area with well-defined lateral ridges in the proximal sector, expanding over an arc of 40 degrees and reaching a width of 6.1 km. The distal sector of the lobe displays polygonal hummocks that grade into progressively smaller, and locally radially aligned, conical hummocks. In the terminal sector, the rock avalanche was emplaced on soft floodplain alluvium, which displays folding with vergence consistent with the impacting flow direction. Two OSL ages in correct stratigraphic order obtained from the deformed alluvium indicate an age of ca. 5.5 ka for the Emad Deh rock avalanche, attributable to a major paleoearthquake. Subsequently, four additional planar failures occurred in the rock avalanche scar, mainly affecting marls and limestones of the Paddeh Fmormation, and resulting in more cohesive flows. The deposits of these later landslides, with volumes ranging between 10 and 45 million m3, are confined by the lateral ridges of the rock avalanche and its scar. Cartographic relationships allow inferring their relative chronology.

How to cite: Gutiérrez, F., Zarei, M., Deirnik, H., Rahimi, M., and Medialdea, A.: Geomorphology and geochronology of the coseismic? Emad Deh rock avalanche of the Zagros MountainsGeomorphology and geochronology of the coseismic? Emad Deh rock avalanche of the Zagros Mountains, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-234, https://doi.org/10.5194/icg2022-234, 2022.

Richard William McIntosh and Jamal Aldin Hosseini Seyed

Studying the relationship between geological conditions and the geomorphology of a landscape has always been in the focus of geomorphology research. The relationship between structural and morphological elements can be analysed on the basis of a morphotectonic approach in which the role of rock strength is clear in slope conditions and thus in the morphology of an area. The strength of natural rock masses, however, cannot be modelled simply by the laboratory measurements of rock strength. The complex approach of rock mass strength is reflected in the development of various rock mass rating methods.

The authors evaluate the strength of natural rock masses in the Bükk Mountains in Northern Hungary based on the rock mass rating of more than a hundred outcrops scattered across the mountains. Some widespread rock mass rating methods are compared and the rock mass strength values of similar and also of different rock types are analysed. The results reveal that rock type has smaller influence on the strength of rock masses than parting conditions. Therefore, the role of parting surfaces needs to be analysed in detail, especially in areas with strong deformation features. On the edge of tectonic blocks where the deformation of rock masses is strongest, sinigficant fault planes with slickensides, folded structures and thrusts with shear zones compose the dense parting surfaces with so strong compression that massive limestone rock masses have smaller rock mass strength values than porous but much less deformed rhyolitic tuff rock masses.

Based on the results, the role of rock mass strength is assessed in the development and orientation of landforms in certain study areas in the mountains. Moreover, the relationship between rock mass strength and valley density is also studied. Finally, we take a look at the relationship between rock mass strength and the dominant deformation elements of the rocks of the mountains to see what tectonic geomorphological implications can be found.

Based on the rock mass rating methods, some recommendations can be given in relation to slope stability in terms of construction geological applications.

How to cite: McIntosh, R. W. and Seyed, J. A. H.: The role of rock mass strength in landscape development based on the rating of natural rock masses in the Bükk Mts., Hungary, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-670, https://doi.org/10.5194/icg2022-670, 2022.

Dilce Rossetti, Davi L. Vasconcelos, Francisco H. R. Bezerra, Marcio M. Valeriano, Fabio C. Alves, and Eder C. Molina

In intracratonic South America, the origin of neotectonic activity and its impact on large Amazonian rivers have been of continuous research interest, but the available evidence has been only for extensional structures. This investigation focuses on a megascale (~60,000 km2) domal relief from central Amazonia (the Juruá dome). The main goal was to verify the relationship of this anomalous relief with a growing fold and determine the origin of the stress field within the context of Andean uplift along with the westward movement of the South American plate. The approach applied here is unprecedented for the Amazon lowlands. This is because it combines evidence of tectonic adjustments of river systems using morphostructural and morphometric analyses from remote sensing imagery, integrated with subsurface data consisting of gravity and magnetic maps, seismic reflection, and well logs. The Juruá dome consists of a broad, rounded, and smooth, convex relief, with altitudes generally not exceeding 110 m developed into Pleistocene-Holocene deposits. The drainage over the dome is arranged concentrically into a broad annular pattern with localized anomalous segments in the Solimões River and various Amazonian tributaries. The results revealed that the Juruá dome evidence the growth of a broad anticline. Non-linear slightly convex χ-profiles of many rivers that cross or contour the dome evidence transient rivers, consistent with a development under growth fold. The fold modified the course of several rivers within the domal relief area, including the Juruá River, which is entrenched along NE-striking faults that released the stress along the fold axis. NE- and NW-striking normal and reverse faults with flower structure geometries are abundant in subsurface and suggest deformation from strike-slip tectonics. Gravity and magnetic data revealed that the fold and many of its associated faults are deep-rooted into basement rocks. The geomorphological and structural data are collectively compatible with a long-term NW-trending maximum horizontal compressive stress-field that is driving basin inversion. This neotectonic activity can be linked to far-field stresses from the pushes from the Andean orogeny and the movement of the South American plate against the North Andean and Nazca plates. Thus, this study can expand our knowledge on the impact of far-field stresses in intracratonic settings transmitted from collisional and constructional tectonic plates. Detecting active folded reliefs in central Amazonia is a new approach that can help characterize the extension and source of compressive far-field stresses in intracratonic northern South America.

How to cite: Rossetti, D., Vasconcelos, D. L., Bezerra, F. H. R., Valeriano, M. M., Alves, F. C., and Molina, E. C.: Late Quaternary large-scale folds in intracratonic central Amazonia evidenced from tectonic geomorphology, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-308, https://doi.org/10.5194/icg2022-308, 2022.

Coffee break and poster session
Chairpersons: António Gomes, Maria Araújo
Valentino Demurtas, Paolo Emanuele Orrù, and Giacomo Deiana

The tectonic structure of Sardinia is linked to the geodynamic evolution of the western Mediterranean during the Alpine phase. In particular, the eastern continental margin is the result of the opening of the Tyrrhenian basin which is still evolving. The Pliocenic and Quaternary distensive phase lead an uplift in Sardinia whose effects are manifested in the geomorphological setting. Morphotectonic analysis were used to characterize paleo and active geomorphological processes in Ogliastra area. Palaeo-erosive surfaces, volcanic mesas, Steep slopes, involute hydrographic basins, widespread landslides shaped the inland, while the submerged continental margin in affected by engraved active canyons and landslide.

To analyze the continental area large scale geological, geomorphological, geostructural, morphostratigraphic surveys integrated by PS-INSAR, Uncrewed aerial vehicle, LiDAR Remote sensing data were used.

Seismic sparker, sub-bottom profiler chirp, multibeam, side scan sonar made it possible to analyze the evolution of the submerged area.

In particular, fluvial captures, river terraces, engraved valleys, waterfalls and heterogeneous water drainage characterize the streams setting. Coastal Quaternary volcanism present relief inversion plateaus. The slope area affected by different kind of landslide conferring at the Ogliastra the main geomorphogical hazard of Sardinia. Widespread Deep seated gravitational slope deformation both active and quiescent are preset in different structural and tectonic setting. Paleo erosive surface since the Carboniferous are found located at different elevation.

The eastern continental margin of Sardinia is made up of a north-south oriented host and grabben system linked to the open Tyrrhenian basin. The continental shelf is very narrow and indented by several narrows and straight submarine canyons. Head retreat processes of the canyons are evident, that have notably affected the continental shelf. The continental slope is made up of intraslope basins and seamounts oriented N-S whose slopes are affected by active and paleo landslides, slumps and erosional incisions.

Multi-source and multi-scale data showed the role of the uplift rebound in the landscape evolution.

High resolution morphotectonic map were reconstructed, highlighted and integrated all different morphologies and process.

How to cite: Demurtas, V., Orrù, P. E., and Deiana, G.: Morphotectonic evolution of eastern Sardinia: relations between inland and the continental margin, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-526, https://doi.org/10.5194/icg2022-526, 2022.

Esra Tunçel Gökkaya, İhsan Çiçek, and Francisco Gutiérrez

The Acıgöl Graben is located in an extensional province of western Turkey, related to combining effects of the southwestward retreat of the Hellenic trench and the westward displacement of the Anatolia Plate. This is a 50 km long and 10 km wide neotectonic depression with a NW-SE orientation that veers into an E-W trend in its southern part. The basin has a late Miocene to Quaternary fill, and according to borehole data Quaternary sediments exceed 600 m. The Acıgöl and Maymundağı Quaternary faults, respectively, control the SE and NW margins of this internally drained basin, which hosts a playa-lake. The higher elevation of the SE mountain front and the proximity of the lake to this margin suggests some asymmetry in the graben structure. This study analyses the graben-bounding faults by means of detailed geomorphological mapping, and demonstrates their late Quaternary activity by geomorphic evince and Optically Stimulated Luminiscence (OSL) dating. The Acıgöl Fault on the SW margin juxtaposes Mesozoic carbonate rocks against Quaternary deposits along the linear mountain front-piedmont junction. The uplifted range, with a local relief of around 1 km, shows geomorphic evidence of deep-seated gravitational slope deformation (DSGSD), such as ridge-top depressions, uphill-facing scarps, internally drained troughs and bulged toes. The SW margin on its southern sector displays E-W intra-basin faults that offset and tilt recent basin-fill deposits, producing backtilting on geomorphic surfaces. These deformations control the anomalous orientation of some drainages that flow towards the basin margin. OSL ages provide a maximum age of 24 ka for the youngest displacement event on these faults. On the NW margin of the graben, the Maymundağı Fault, with a NW-SE to E-W orientation, is expressed as a linear mountain front with triangular facets up to 700 m high. This fault juxtaposes Oligocene conglomerates against Quaternary alluvial fan deposits. In the southern section where the basin attains an E-W trend, the fault displays two parallel fault strands. The northern fault strand is the master basin bounding fault located at the toe of the mountain front, whereas the southern one is an intra-basin fault expressed as a scarp that offsest alluvial fan surfaces and deposits. Here we differentiate two generations of alluvial fans: (1) oversteepened and dissected old fan surfaces restricted to the footwall block; and (2) active fans in the downthrown block with their apex at intersections points associated with the fault scarp. Numerical ages indicate fault activity younger than 3 ka.

How to cite: Tunçel Gökkaya, E., Çiçek, İ., and Gutiérrez, F.: Tectonic geomorphology of the Acıgöl Graben, western Turkey, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-263, https://doi.org/10.5194/icg2022-263, 2022.

Edna Facincani, Marcelo Assumpção, Pedro Cunha, and Estevão Tadeu

The largest expression of neotectonics in the State of Mato Grosso do Sul is documented in the Pantanal Sedimentary Basin, considered a N-S tectonic trench, with 400 km in length, 250 km in width and a sedimentary thickness of > 400 m. The Pantanal Basin is located in the west of the Mato Grosso do Sul state, occupying an area of 135,000 km². The Pantanal Plain is surrounded by the Maracaju-Campo Grande and Taquari-Itiquira plateaus to the east, Guimarães and Parecis to the north, Urucum-Amolar to the west and Bodoquena to the south. The region is surrounded by plateaus in rocks that range from the Precambrian to the Cenozoic. Historically, the Pantanal Basin is considered one of the seismic regions of Brazil. Intraplate earthquakes mainly result from ruptures along zones of preexisting weaknesses, located close to structural inhomogeneities, which concentrate efforts that, added to regional efforts, are capable of generating earthquakes. The main structural features identified are expressed by joints, faults and fault zones. Two main sets of fault types were recognized: normal and transient. The normal faults are those related with the NE-SW opening of the basin, while the transcurrent faults are younger and characterized by an E-W direction. The direction of the binary E-W and dextral movement enable the development of NW-SE discontinuities. The drainage network and the structure of the landforms are strongly controlled by these structural discontinuities, associated with the collapse of blocks. This allows the development of areas with greater subsidence and accommodation space for Holocene sediments in the basin, such as the so-called “Brejão do Negro”, which proved to be a frequently flooded area, marked by a hidden fluvial lake due to a floating mat of macrophytes. The Rio Negro lineament is an important seismic-tectonic feature in the southeastern portion of the Pantanal Basin, functioning as an E-W shear zone, with current neotectonic movement, forming a pull-apart rhombohedral structure. The earthquakes in the Pantanal Basin present values between 0.6 to 5.4 mb. In the brittle shear region comprised by the Negro lineament (area comprised by the Brejão do Negro), the magnitudes are higher, usually between 3.0 and 4.0 mb. Recent earthquakes recorded in this basin are the result of uniform E-W compression stresses. These lineaments impose tectonic landforms, being indicated by subsidence, escarpment, fluvial avulsions and captures, elbows, rectilinear lake edges, among others, associated with evidences neotectonic activity in the Pantanal Basin. From surveys focused on the identification of structural discontinuities and seismological activity, two tectonic events were identified for the area: the first being distensive, associated with the opening of the basin, and the second of transcurrent character.

How to cite: Facincani, E., Assumpção, M., Cunha, P., and Tadeu, E.: Neotectonics and Seismicity in the southeast edge of the Pantanal Basin (Mato Grosso do Sul, Brazil), 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-296, https://doi.org/10.5194/icg2022-296, 2022.

Efthimios Karymbalis, Kanella Valkanou, Giandomenico Fubelli, Maria Ferentinou, Konstantinos Tsanakas, and Philip Giles

The geomorphometric analysis of mountain fronts, drainage networks and catchments in tectonically active areas can provide valuable information about the spatial distribution of relative tectonic activity. The aim of this study is to investigate the contribution of neotectonics to the development of the fluvial landscape of the broader Trichonis Lake area (located in western continental Greece) through quantitative geomorphological analysis. The Trichonis Lake graben is a is a late Plio-Quaternary extensional basin, which cuts across the early Tertiary NW-SE fold and thrust structures of the Pindos Mountain belt. It strikes WNW–ESE for a distance of 32 km and has a width of 10 km. The graben at the north and south flanks of the lake is bounded by E-W and NW-SE trending faults. Recent seismic activity (a shallow earthquake sequence in 1975 and a 2007 earthquake swarm) showed the existence of a NNW-SSE normal fault that dips to the NE and bounds the SE shore of the lake. The studied catchments have developed on the hanging walls of these active normal faults. To evaluate the relative tectonic activity in the study area, various morphometric indices including stream length-gradient index, drainage basin asymmetry factor, hypsometric integral, valley floor width-valley height ratio, drainage basin shape, drainage basin slope, relief ratio and Melton's ruggedness number were measured for 35 catchments. In addition, mountain-front sinuosity index has been estimated for 20 mountain fronts around the lake. For the measurement of the geomorphometric variables a digital elevation model (with 5 m cell size), derived from topographic maps at 1:5000 scale (with 4 m contour lines), was used. The catchments of the study area were classified into three classes based on the morphometric variables and a series of maps showing their spatial distribution were produced by applying GIS techniques. The combination of these morphometric variables yielded two new indices of relative tectonic activity (named IRTA: Index of Relative Tectonic Activity and IAT: Index of Active Tectonics). Based on the values of IRTA and IAT, the area was classified into three classes of relative tectonic activity (low, medium, and high). To evaluate the landscape around Lake Trichonis in terms of neotectonic activity, we identified clusters of drainage networks and catchments according to their geomorphic characteristics (expressed by the geomorphometric indices) using self-organizing map, which is a type of unsupervised artificial neural network (ANN). The analysis showed that the development of the landscape of the central part of the northern flanks of the graben has been highly influenced by the tectonic uplift since these catchments are characterized by high IRTA and IAT values which correspond to high relative tectonic activity. The study of these fault-generated mountain fronts showed that although both graben flanks have low sinuosity index values, the central segment of the north flank of the graben has slightly lower values which are indicative of active tectonics.

How to cite: Karymbalis, E., Valkanou, K., Fubelli, G., Ferentinou, M., Tsanakas, K., and Giles, P.: Assessment of relative tectonic activity in the Trichonis Lake graben (Western Greece) a combined approach using geomorphometry and Self Organising Maps, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-368, https://doi.org/10.5194/icg2022-368, 2022.

Ettore Valente, Ciro Cerrone, and Alessandra Ascione

The growth of a mountain chain results from a complex interplay between endogenous and exogenous processes. The former depends on the geodynamic setting and cause the uplift of the orogenic wedge whereas the latter tend to erode the uplifted topography. Surface uplift may act at uneven temporal and spatial scale and reconstructing its distribution through space and time may provide fundamental data to unravel either the future tendency of geomorphic processes (e.g., increased erosion in uplifted areas) or to identify areas affected by active tectonics. In this study, we adopted a morphotectonic approach to unravel the spatial distribution of surface uplift in active orogens, such as the southern Apennines of Italy. Features of the topography (e.g., maximum, mean and minimum elevation maps, relief maps and swath profile) and the river network (e.g., river long profile and chi-long profile, Ksn index, chi index map) have been derived through ArcGis and Matlab softwares. The combined analysis of all indexes allows recognising a locus of enhanced surface uplift that moves from NE (the Bradanic foredeep) to the SW (the outer sector of the orogenic wedge). Surface uplift do not extend towards the inner sector of the orogenic wedge and its spatial distribution roughly follow the main divide. Furthermore, a natural tendency of the main divide to shift towards the NE has been also identified, that is consistent with the uneven spatial distribution of vertical motions. To quantify differences in surface uplift between the foredeep-outer chain and the inner chain, we analysed published data about MIS5 paleoshorelines. These data also confirmed the uneven distribution of surface uplift at the orogen scale, thus confirming that the adopted morphotectonic approach may be considered a powerful tool to constrain the spatial distribution of vertical motions.

How to cite: Valente, E., Cerrone, C., and Ascione, A.: Detecting differential surface uplift at the orogen scale by topography and river network features: the Southern Apennines case study (Italy), 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-416, https://doi.org/10.5194/icg2022-416, 2022.

Francesco Troiani, Michele Delchiaro, Natacha Gribenski, Marta Della Seta, Giulia Iacobucci, Daniela Piacentini, and Marta Zocchi

Along the Adriatic piedmont zone of central-northern Apennines of Italy, the combination of tectonic uplift with Quaternary climate changes caused the alternating phases of fluvial incision and deposition that eventually produced at least four levels of fluvial terraces. Although the fluvial terraces of this sector of the Apennines have been object of many studies since the first half of the twentieth century, their chronology is still object of debate. Consequently, their use as geomorphic markers of landscape evolution can be challenging. The scarcity of geochronological constraints, especially for the older terraced deposits, in addition to the extreme spatial variability of the terrace geomorphological characteristics along adjacent valleys and within different sectors of the same valley, are the main limitations to the utility of fluvial terraces as geomorphic markers of landscape evolution in this sector of the Apennines. This research presents new geomorphological data for the different terrace generations exposed along the southern Marche Apennines between the middle Pleistocene to the late Pleistocene-Holocene, using remote sensing techniques and field investigation, as well as geochronological data from Optically Stimulated Luminescence (OSL) analysis. The fluvial terrace staircase along the Tesino River valley has been selected for the excellent exposure of the different terrace generations along the valley sides, the good accessibility for sampling, and the geomorphological characteristics of the river valley that can be representative of the ones draining the central-northern Adriatic piedmont zone. Findings from this research are useful for enhancing the knowledge on the evolution of the central-northern portion of the Apennines, providing new constraints for unravelling the contributions of tectonics and climate on the late Quaternary evolution of river valleys in the mid-latitudes zone of the Northern hemisphere.

How to cite: Troiani, F., Delchiaro, M., Gribenski, N., Della Seta, M., Iacobucci, G., Piacentini, D., and Zocchi, M.: Geomorphology and geochronology of the Quaternary fluvial terraces of the Tesino River: new constraints to the landscape evolution in the piedmont area of central-northern Apennines of Italy, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-57, https://doi.org/10.5194/icg2022-57, 2022.

Kanella Valkanou, Efthimios Karymbalis, Emmanuel Vassilakis, Mauro Soldati, Dimitris Papanastassiou, and Kalliopi Gaki-Papanastassiou

Τhis study aims to investigate to what extent the drainage systems of the northern part of Evia Island, in Central Greece, reflect the contemporary tectonic regime of the area. The effects of tectonic activity have been detected and described by performing a landscape morphological analysis of the drainage systems, followed by a field survey for validating the results. The Relative Declivity Extension (RDE) index, which is based on the Stream Length (SL) gradient index, was calculated along the channels of 189 drainage basins of the study area, using the Knickpoint Finder tool integrated into ArcGIS desktop. The Hack RDE index is defined by the ratio of the RDEs index (which refers to a stretch) and the RDEt index (which refers to the total length of a river) was applied, and its calculation identifies the knickpoints based on anomaly values detection along the longitudinal profiles of the rivers. Furthermore, knickpoint analysis was carried out along the channels of the drainage networks of the northern part of the Evia Island and the corresponding anomaly maps were designed. A total of 2,486 knickpoints were identified and the greatest anomalies (139 points), named first-order anomalies (RDE>10), seem to correspond to a recently shaped or rejuvenated landscape, indicative of intense neotectonic activity. In some cases, the spatial distribution of knickpoints delineates a NW-SE trending yielding the structural control of the study area. The comparison of the results with the lithological map of the area showed that about 30% of the knickpoints are lithologically controlled. The identification of zones of neotectonic activity and consequently the existence of active faults is highly correlated with the distribution of knickpoints and their core density, the drainage density, the drainage asymmetries, and other morphometric indices such as the hypsometric integral, along with the earthquake epicentres, and the morpho-lineament density. The overall analysis showed a positive correlation of the concentration of the derived knickpoints with both active structures and tectonic activity rates. The results were consistent with field observations, which were mainly focused on waterfall landforms. Our study proves that the landscape evolution of the northern part of the Evia Island is considerably affected by the recent activity of normal fault zones, whereas the drainage systems react to the changes of base-level providing insights on active tectonics.

How to cite: Valkanou, K., Karymbalis, E., Vassilakis, E., Soldati, M., Papanastassiou, D., and Gaki-Papanastassiou, K.: Knickpoint extraction for the evaluation of active tectonics: The case of Evia Ιsland, Greece, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-370, https://doi.org/10.5194/icg2022-370, 2022.

Ettore Valente, Anna Sorrentino, and Nicola Mondillo

A morphometric approach, based on the investigation of the topography and river network features of two hydrographic basins, Utcubamba and Chiriaco, was applied to determine the relationship between the irregular distribution of vertical motions (e.g., surface uplift) and the genesis of supergene Zn deposits located in the Bongará district, in the north-eastern sector of the Peruvian Andes. In the area three mixed supergene-hypogene ore deposits have been recognized: Mina Grande, Cristal and Florida Canyon. The Florida Canyon deposit falls within the Eastern Cordillera, in the Utcubamba Basin, and represents one of the most important Zn-Pb MVT deposits hosted in the carbonate and former evaporite-bearing rocks of the Pucarà Group. The mineralization consists mainly of sulfides and only one-third of the resource is nonsulfides and is hosted in Triassic rocks. The Mina Grande and Cristal deposits fall within the western margin of the Subandean Fold-and-Thrust Belt, in the Chiriaco Basin, and consist mainly of nonsulfide ores with less sulfides hosted in more recent Jurassic rocks. The MVT sulfide mineralizations formed at the same time (70 – 80 Ma) at two different depths of 2,500 - 3,000 m b.s.l. for Florida Canyon and 1,5000 - 2,000 m b.s.l. for Mina Grande - Cristal and currently outcrop approximately at the same altitude of around 2,700 m a.s.l. Since the late Oligocene, when Andean deformation migrated eastward from the Western Cordillera to the present Sub-Andean zone, the rocks of the Pucará Group were repeatedly uplifted and eroded allowing the exhumation of primary sulfide bodies and the formation of the supergene deposits.

The research has been carried out through the evaluation of the parameters such as elevation, local relief, swath profile, river longitudinal profiles, slope/area analysis to derive the normalized channel steepness index (ksn) and transformed river profiles (χ-long profiles). The spatial distribution of such indexes allowed to derive some consideration about the spatial distribution of vertical motions (e.g., surface uplift). Furthermore, the sharp increase in maximum, mean and minimum elevation moving from the Utcubamba Basin to the Chiriaco Basin, coupled with a jump in the mean Ksn values, suggest that the Chiriaco Basin has experienced either more recent surface uplift or surface uplift at rates higher than the Utcubamba Basin. This trend seems to be confirmed by the uneven erosion that the Florida Canyon and the Mina Grande – Cristal deposits have experienced. In fact, the Utcubamba Basin has been subjected to an uplift protracted in the time, resulting in a rugged local relief and lowering the mean and minimum elevations, which would have removed the Jurassic succession and exposed at the weathering the Triassic-hosted Florida Canyon. In the Chiriaco Basin, the higher surface uplift in terms of time and/or rate has exposed at the weathering the Jurassic-hosted Mina Grande – Cristal deposits allowing the almost complete alteration of primary sulphides and the development of non-sulphide mineralization.


How to cite: Valente, E., Sorrentino, A., and Mondillo, N.: Deciphering the spatial distribution of surface uplift in a sector of the Andean chain and its implications for supergene ore deposits formation, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-418, https://doi.org/10.5194/icg2022-418, 2022.

Display time: Mon, 12 Sep 09:00–Tue, 13 Sep 19:00

Poster: Mon, 12 Sep, 16:30–16:45 | Poster area

Chairpersons: António Gomes, Maria Araújo, Marta Della Seta
Paola Molin, Andrea Sembroni, Claudio Faccenna, and Paolo Ballato

Continental collisional zone may include high-standing plateaus, both internally and externally drained. When endorheic basins are integrated into external drainage networks, the rivers could retain first order information on the capture as well as the interplay between climate and tectonic processes. The Eastern Anatolian Plateau (EAP) of the Arabia-Eurasia collision zone is one of the most representative examples of collisional plateau. It has a mean elevation of ~2000 m, presents three main endorheic basins (Van, Sevan and Urmia lakes), and is mostly drained by three river networks: the Kura-Arax drainage system to the NE, the Ҫoruh to the NW, and the Euphrates-Tigris to the SW. Seismic data indicate the presence of a thinned or totally removed lithospheric mantle beneath the plateau explaining the high heat flow and the late Cenozoic volcanic activity in the area. Despite the great number of studies on the EAP, its uplift history is still debated.

In this study we quantitatively investigated the drainage systems (river longitudinal profiles and chi-plots) and the general topographic features (swath profiles, slope, local relief, filtered topography) of the EAP. The results describe a topographic configuration characterized by a high-standing, low-relief plateau centered in the area of Lake Van, but strongly disrupted by tectonic structures with the formation of local topographic highs and lows that include endorheic basins. The fluvial network pattern is strongly disorganized and controlled by active tectonic structures. The irregular longitudinal profiles indicate that rivers are in a transient state of disequilibrium because of regional uplift, capture events or local tectonic activity. The presence of an uppermost fluvial segment characterized by low channel steepness suggests that the plateau interior has not been reached yet by the erosive wave produced by uplift. The chi-plots of the rivers draining the EAP suggest a complex uplift history, evidencing differences between the northern and the southern portions of the plateau in terms of uplift history and drainage system evolution. This uplift pattern is partially confirmed by the stratigraphic record documenting a southward younging transition from a marine to a continental depositional environment. In conclusion, the EAP is a high-standing plateau where the integration of hydrography into it is ruled by regional differential uplift and active tectonic structures.

How to cite: Molin, P., Sembroni, A., Faccenna, C., and Ballato, P.: The uplift of the Eastern Anatolian Plateau unraveled by river network analysis., 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-119, https://doi.org/10.5194/icg2022-119, 2022.

Mohammad Moumeni, Michele Delchiaro, Marta Della Seta, and Reza Nozaem

Drainage divides, the elevated terrain that separates neighboring drainage basins are dynamic features of a landscape that regularly migrate over time due to the development of river networks. Tectonic uplift may considerably influence such a migration by making some basins aggressors with respect to the adjacent ones. In this study, we focus on the effects of tectonic uplift on the Ardebil Basin drainage divide located adjacent to the central Talesh Mountains in the NW sector of Iranian Plateau. Talesh Mountains are prominent tectonic features of the landscape associated with the compressional stresses transferred from the Arabia-Eurasia continental collision. The structural evolution of this range is delineated by several deformation phases in the Late Cenozoic. The regional uplift associated with the right-lateral strike-slip kinematics with a reverse component of the N-NW-trending Talesh Fault, which bounds the Talesh Mountains to the east, has an important role in the tectonic activity of the region. The effects of these tectonic uplift and deformation phases on the landscape and their footprints on the geomorphological architecture of the study area are not fully described to date. Therefore, we used the tools for quantifying drainage divide stability (χ and Gilbert metrics) in order to outline the spatial pattern of uplift in this area. Since, a single divide may be heterogeneous in channel elevation, relief, and gradient values in its different portions, we segmented the Ardebil Basin main divide into 14 sections to calculate the Gilbert metrics and χ. Considering the uniformity of the cross-divide precipitation and rock erodibility, we can infer that divide migration is occurring in the study area in response to the asymmetric uplift and erosion patterns. The results of Gilbert metrics show that the NW and SE sectors of the Ardebil Basin divide are stable, suggesting a quasi-steady state condition. However, based on the χ index, these segments have the potential to move towards the interior of the plateau. Conversely, the NE segments of the main divide are dynamic and currently moving towards the SW, as suggested also by the χ index map. Therefore, we infer that the NE sectors of the Ardebil Basin are in an uplift-driven migration status as a result of an asymmetric uplift controlled by the activity of the Talesh Fault.

How to cite: Moumeni, M., Delchiaro, M., Della Seta, M., and Nozaem, R.: Asymmetric uplift in the NW Iranian Plateau: An insight from the dynamic divide migration of Ardebil Basin, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-120, https://doi.org/10.5194/icg2022-120, 2022.

Victor Buleo Tebar, Mauro Bonasera, Ionut Sandric, Giandomenico Fubelli, and Viorel Ilinca

Mechanisms and processes that have led to the formation of curved orogenic belts are widely studied and still discussed around the world. Europe has witnessed the formation and evolution of a few cases, among which are the Western Alps (and Alps-Apennines inference zone) and the curvature zone of Romanian Carpathians, both formed during Alpine orogeny. Despite the differences regarding the tectonic evolution between these two different ranges, foreland basins are present in both cases as the result of the geodynamic processes related to deformation during the collisional phases. These subsurface features, filled with deposits of material eroded from the surrounding mountain ridges, often turn into flat surfaces resulting from the deposition of sediments. Under such conditions, any signature or features of tectonic activity are not easily recognized in the visible landscape. However, anomalous changes in fluvial geomorphology, characteristics of drainage patterns and topographic setting along drainage network systems are among the elements that can provide relevant information of recent tectonic activity in areas where the main signatures and tectonic features might be buried by thick layers of sediment eroded from the adjacent mountain ranges. This study aims is to analyze topographic features in these mountain ranges through a morphometric approach using GIS techniques. This approach enables evidence of active tectonics to be identified and, consequently, potential seismic hazard for those areas where knowledge of seismogenetic sources is still limited. In addition, certain aspects of the tectonic evolution of these areas might be more clearly understood with the new information obtainable from such study. Morphometric analysis based on 5 m and 10 m resolutions DEM supported by geological and geomorphological field investigations provided evidence of compressive tectonics activity referable to recent times. Stream-Length Gradient (SL) and Normalized Steepness index (Ksn) are some of the indices that have been calculated using open-source QGIS software.

How to cite: Buleo Tebar, V., Bonasera, M., Sandric, I., Fubelli, G., and Ilinca, V.: Geomorphic signature of active tectonics in European foreland basins: morphometric analysis of drainage network systems of Western Alps and Romanian Carpathians, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-271, https://doi.org/10.5194/icg2022-271, 2022.

Vasileios Antoniou, George D. Bathrellos, and Hariklia D. Skilodimou

In many cases tectonism influences the evolution of morphology and hydrographic networks. The study area is Lavreotiki which is located at the southeastern most tip of the Attica peninsula in the Greek regional unit of East Attica.

The aim of this study was the determination of the geotectonic structure and the paleogeographic evolution of the drainage basins of the study area. For this purpose, classic mapping techniques such as detailed field work along with large scale geomorphological and geological mapping were performed. Moreover, remote sensing data were used, a spatial database was created, and ArcGIS 10.8 software was used to process the collected data.

Quantitative geomorphological analysis of the drainage networks was accomplished. Fourth and higher order streams were taken into account. Surface analysis of the study area was performed, while geomorphic indices were calculated. The geomorphic indices of active tectonics used, were slope and aspect of terrain, hypsometric curve and hypsometric integral, drainage basin asymmetry, mountain – front sinuosity and longitudinal river profiles.

How to cite: Antoniou, V., Bathrellos, G. D., and Skilodimou, H. D.: Surface analysis and geotectonic structure of Lavreotiki, Attica peninsula, Greece, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-562, https://doi.org/10.5194/icg2022-562, 2022.

Daniela Schievano de Campos, Marcilene dos Santos, Karina P. P. Marques, Alexandre Christófaro Silva, and Pablo Vidal-Torrado

Post-rifting and dead orogens landscapes have presented topographic rejuvenation long after intense tectonic activity ceased, resulting in relief growth in a topography that was expected decay.In addition, there is compelling evidence of low denudation rates in tropical post-orogenic landscapes, mainly related to low-relief uplands capped with duricrusts.Thus, understanding the evolution of these landscape settings has proven enigmatic. Recent studies have invoked the contrasting rock strength as primary factor for such topographic rejuvenation. In contribution to this issue, we investigated the topographic signals in a post-orogenic and post-rifting Brazilian landscape with low contrasting rock strength, the Southern Espinhaço Range(SER). In order to reveal potential relief growth, we explored interactions between drainage signatures, topographic metrics, bedrock inheritance and duricrusts. We extracted local relief, hillslope angle, and normalised channel steepness, and performed knickpoint and stream profile analysis to explore spatial variations in topography of the study area. Our findings suggest that the post-rifting evolution of the study area is dictated by episodic uplift and base level fall events coupled with favored stress concentrator zones, which accelerate channel incision and trigger ongoing dismantling of duricrusts. Knickpoints at high elevation separate a relict low-relief landscape upstream, capped by either Fe or Al duricrusts, from a transient adjustment zone downstream, indicating that records of different boundary conditions coexist in the landscape. This study shows a contradiction between low denudation rates and topographic rejuvenation even in a low contrasting rock strength domain. We have found that interactions between surface processes and pre-existing weakness zones likely occur in the SER, highlighting how enigmatic and complex long-term landscape evolution can be in ancient post-orogenic and post-rifting settings.

How to cite: Schievano de Campos, D., dos Santos, M., P. P. Marques, K., Silva, A. C., and Vidal-Torrado, P.: Topographic rejuvenation of an elevated post-rifting landscape with low contrasting rock strength(Southeast Brazil), 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-717, https://doi.org/10.5194/icg2022-717, 2022.

Devi Datt Chauniyal


       Formation of river terraces, transverse faults along with the major thrusts, deformation of quaternary sediment, and mass movement results from the combined effect of the tectonic and climatic process, tectonic landforms developed across defining the boundary of North Almora Thrust (NAT) have imprints of late Holocene tectonic activities. The reactivation of thrust and faults has greatly influenced the topography of the Himalayan region. Considering this a series of geomorphic evidence of the Quaternary period has been reported along the strike-slip transverse fault near NAT at Kirtinagar in Lower Alaknanda valley of the Lesser Himalaya. Present tectonic landforms of the transverse fault indicated by various cutting of host rock, V-shaped valley, epigenetic gorge, unpaired river terrace, deflecting river course, offset drainage pattern, triangular facet, incision with higher uplift along with tectonic upheaval, and immature topography. The neo-tectonic sites were identified along with the road cut section and Kirtinagar terrace scarp. The tectonic structures and nature of sediments were analyzed and photographed during the field study. The minor structural features of Quaternary sediments are folding, faulting, thrusting, warping, and tilting. The samples of optical chronology were collected from discrete sand horizons. The OSL date was obtained using the single aliquot regeneration. The Optical Chronology of terraces sediments shows that the T2 and T3 levels of terraces are deposited around 4.6 Ka in the Holocene periods. Based on existing data it is assumed that the Lesser Himalayan thrust and faults were tectonically active during the early Holocene period. After that, the role of tectonic decreases and incision increases due to the climatic variability. The conclusive results of the study indicate that the neo-tectonic movements along NAT were more active in recent past times. It is concluded that the transverse strike-slip fault along NAT in the study section has been reactivated from time to time

Keywords- Neo-tectonics; Deformation; North Almora Thrust; Transverse fault; Quaternary period.

How to cite: Chauniyal, D. D.: Evidences of Late Quaternary Neo-Tectonics at Kirtinagar in Alaknanda Valley of Garhwal Himalaya, India, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-661, https://doi.org/10.5194/icg2022-661, 2022.

Kanella Valkanou, Efthimios Karymbalis, Konstantinos Tsanakas, Mauro Soldati, Dimitris Papanastassiou, and Kalliopi Gaki-Papanastassiou

The drainage networks are very sensitive to changes caused by the interactions between tectonic activity, climate, and earth’s surface processes and thus contain useful information on the landscape development. Drainage networks and catchments located on the footwall of normal faults are excellent archives for understanding and quantifying the active deformation processes. This study aims to identify stream piracies due to tectonic activity, to record the main factors that facilitated river captures, as well as to identify and interpret lateral tilting of river valleys. The study area includes 3 drainage networks and their corresponding catchments (ranging in area between 15.2 km2 and 29 km2), located at the eastern slopes of the Dirfis Mountain range, in Evia Island, Central Greece. The rough landscape of the area and the evolution of the drainage networks seem to be strongly controlled by the neotectonic activity of the offshore Dirfis normal fault zone. Selected morphotectonic parameters including Asymmetry factor (Af), Transverse topographic symmetry factor (T), Mountain front sinuosity (Smf), and Valley height-width ratio (Vf) were estimated for the drainage networks and their catchments, whereas the longitudinal profiles of the main streams’ channels were constructed and analyzed. All three streams are characterized by active headward erosion and intense incision. Along the main streams’ channels a large number of knickpoints, mainly of tectonic origin, were detected. The results suggest that the evolution, the shaping up and the patterns of the drainage networks along with the morphological characteristics of the valleys and the stream longitudinal profiles anomalies are controlled by neotectonics. The stream piracies in the study area (network adjustments, abrupt changes in flow direction, elbow of capture), result mainly from changes in response to the activity of the local fault zones of the eastern slopes of Dirfis Mountain range and reveal the effect of both tectonic uplift and tilting.

How to cite: Valkanou, K., Karymbalis, E., Tsanakas, K., Soldati, M., Papanastassiou, D., and Gaki-Papanastassiou, K.: Stream piracy and tectonic control on the evolution of drainage networks: A case study from the Island of Evia, Greece., 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-366, https://doi.org/10.5194/icg2022-366, 2022.

Jongmin Byun

High-elevation steep escarpments in the passive continental margins are known to have resulted from long-lasting erosion following rifting-related marginal uplift. However, recent studies have revealed that rifting-related processes alone do not explain the high-elevation marginal escarpment. Particularly, post-rift rejuvenation could contribute to the growth of the relief of the long-lived escarpment. A steep escarpment rising above 1,700 m occurred along the eastern margin of the Korean Peninsula. It is known to be a compartment of the passive continental margin, which has been tectonically stable since the extension of a back-arc sea (i.e., the East Sea). Nevertheless, coastal terraces indicative of enhanced tectonic uplift are observed along the eastern coastline. Thus, the steep escarpment has been tectonically reactivated since the Late Quaternary. Knickzone is a geomorphic marker that can decipher the role of tectonics in landscape evolution. This study examined and classified the knickzones of the catchments draining the marginal escarpment, and simulated the response of river profiles to an enhanced tectonic forcing to geomorphologically assess the post-rift tectonic perturbation and understand its effects on the evolution of the marginal escarpment. Firstly, the knickzone analysis identified 52 knickzones, of which 15 were slope-break knickzones, usually interpreted as being transient. However, all slope-break knickzones were not transient but were stationary since they were associated with spatial heterogeneity in erosional resistance. Secondly, river profile evolution modeling illustrated that an abrupt slope break of a transient knickzone developed by an enhanced uplift rate is diffused rapidly during its migration under the condition of a steep marginal escarpment with high channel concavity. Additionally, the tilted uplift pattern induced a newly adjusted river profile of a lower channel concavity, consequently decreasing the steepness of the marginal escarpment. In conclusion, the marginal escarpment in the study area would have been being adjusted since the post-rift tectonic enhancement without the development of typical slope-break transient knickzones, reducing its steepness. These finding suggest that the slope-break knickzone should be used carefully in assessing landscape transience of the marginal escarpment.

How to cite: Byun, J.: Missing evidence of landscape transience: Examination of the knickzones in a steep marginal escarpment in the Korean Peninsula, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-517, https://doi.org/10.5194/icg2022-517, 2022.

Genaro Martinez-Gutierrez, Yahil Emmanuel Hernández-Salgado, José Luis Antinao, and Tina Niemi
The Santa Rosalia Basin (SRB), in the Baja California peninsula, Mexico, is related to the transtensional rifting of the Gulf of California and shows evidence for being tectonically active at least during the Pleistocene. The basin has characteristic sequences of non-symmetrical Pleistocene fluvial and marine terraces with remarkable stream incision and widening of the watersheds. Morphotectonic analysis of four major watersheds in the SRB is conducted to relate their spatial variation of marine-fluvial terraces with the regional tectonic deformation. Six to seven different terrace levels were identified within the Infierno, Boleo, Purgatorio, and Santa Agueda watersheds. Field mapping supported by measurements using RTK-GPS, which were linked to soil chronosequences profiles and luminescence dating provided morphochronology of the different terraces. The elevation of the terrace levels correlated between watersheds display a southward variation from ~6 to ~9 meters in the Boleo-Purgatorio profiles analysis and a difference in height from ~28 to ~50 meters in the Purgatorio-Santa Agueda profile. Geomorphic indices such as asymmetry factor (AF) and transverse topographic symmetry factor (TS), and hypsometric integral curves (HI) were to obtained using GIS. Watershed hypsometric curves show a southward increase of watershed maturity in the arroyos of the SRB. The AF displays variation of 33.5% for Arroyo Boleo, 36.23% for Arroyo Purgatorio, and 55.09% for Arroyo Santa Agueda, suggesting a southward decreasing in the watershed tilting across SRB. The average of TS for each watershed is consistent with the southward variation of the AF index, values of TS varies from 0.42, 0.33 to 0.23 (Arroyo Boleo, Arroyo Purgatorio, and Arroyo Santa Agueda, respectively). Correlation of geomorphic indices and fluvial geomorphology elements of the SRB indicates a possible influence of a differential tectonic uplift towards La Reforma Caldera, displaying a southward tilting of the watersheds. In addition, the delineation of main watersheds of the SRB and mapping of its marine-fluvial terraces can be helpful for future studies on fluvial geomorphology and tectonics influence in the region.

How to cite: Martinez-Gutierrez, G., Hernández-Salgado, Y. E., Antinao, J. L., and Niemi, T.: Morphotectonic Analysis of Uplifted Watersheds in the Santa Rosalía Basin, Baja California Sur, México., 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-498, https://doi.org/10.5194/icg2022-498, 2022.

Girolamo Dixit Dominus, Deborah Maceroni, Emanuela Falcucci, Fabrizio Galadini, Stefano Gori, Paola Molin, Marco Moro, and Michele Saroli

Up to now, the complexity and the uncertainty in defining the extent down-dip and along-strike of active faults led to the elaboration of several methods to establish structure 3D geometry. Therefore, different approaches produce different scenarios of seismogenic rupture for the same active tectonic structure. Here we investigate two active fault systems of the central Apennines of Italy: the Roveto Valley Fault and the Laga Mts. Fault. We specifically aim to the understanding of along-strike segmentation of these tectonic structures to contribute to improve the knowledge of the seismotectonic setting of the central Apennines. Overall, our goal is to make a step forward toward the comprehension of the wide theme of seismogenic fault segmentation.

The main uncertainties regarding the two fault systems are different. In the case of the Roveto Valley Fault, the uncertainty is twofold: 1) the current activity of the fault is debated; according to some authors, fault activity ended during the Middle Pleistocene, whereas others suggest the fault is still active and seismogenic; 2) the extent of the proposed active section of this tectonic structure is not clearly defined, and this is relevant in a seismotectonic perspective. The Laga Mts. fault system is a complex tectonic structure whose activity is well geologically documented for the southern section of the system; moreover, the fault system played a key role in the seismogenic process of the 2016-2017 central Italy earthquake sequence. Some authors interpret the fault as the surface expression of a single large seismogenic source, capable of generating seismic events of Mw ≈ 6.7. Other authors, instead, propose that this system consists in two structurally aligned but kinematically independent faults, the Amatrice and Campotosto faults. Following the 2016-2017 seismic sequence, an important debate is taking place within the scientific community about the definition of 1) the individual seismogenic sources that make up the Laga Mts. fault system and 2) the geometric and kinematic relationship between the fault(s) at surface and its (their) possible prolongation at depth as crustal major seismogenic sources.

Through morphological, morphotectonic and structural analyses we propose segmentation criteria and possible segmentation scenarios for these two structures. These allow us to estimate the maximum coseismic rupture and the maximum magnitude expected from a single seismic event for the investigated fault, improving the seismotectonic knowledge of the central Apennines.

How to cite: Dixit Dominus, G., Maceroni, D., Falcucci, E., Galadini, F., Gori, S., Molin, P., Moro, M., and Saroli, M.: Geological and morpho-tectonic analysis for defining active fault segmentation: case studies from the central Apennines, Italy, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-150, https://doi.org/10.5194/icg2022-150, 2022.

Rafael Palaiopanis and Nikolaos Zouros

The island of Lesvos is located in the North Aegean, a region with high seismicity, directly affected by the southern branch of the North Anatolia Fault (NAF) which is an active right-lateral strike-slip fault.

The purpose of this study is the localization, recording and cartographic mapping of neotectonic structures and macro-seismic effects on the volcanic rocks of Western Lesvos, after the occurrence of an earthquake in ​​Skalochori. The earthquake was shallow - focal depth 6km -, with its epicenter in the inland, 44km NNW of Mytilene and the geological background of the area consists of volcanic rocks and quaternary deposits.

In this paper we collect seismological data from research institutes in the area, we collect and analyse data from the field and we review of published research and data on the active trend field in the North Aegean region.

The fieldwork identified a variety of evidence in a major NNW-SSA address band,10km long and 7km wide. They mainly concern surface ruptures, movements/falls of rocks and small landslides. Their main characteristics are the small size (cracks of millimeters to a few centimeters, volume drops of a few m3), which show a specific and systematic appearance and distribution in space. A left-lateral strike-slip fault was also detected.

The correlation of the main direction of the ruptures, the arrangement of the epicenters, the seismic moment tensor solution and the fault, in combination with the existing research leads to the conclusion that the evidence collected is related to the recent seismic activity and is identical with the existing active field.

How to cite: Palaiopanis, R. and Zouros, N.: Surveying of neotectonic structures and macro-seismic effects on the volcanic rocks of Western Lesvos. A case study: The earthquake in Skalochori, Lesvos (4.0 Mw) of 15 April 2021, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-219, https://doi.org/10.5194/icg2022-219, 2022.

Fernando Carlos Lopes, João Pratas, and Victor Vicente

Timor island is located north of Australian Continent and is one of the southeasternmost Sunda islands. In a tectonic context, is located at the collisional margin between the oceanic Banda volcanic arc and the Australian continental margin. The island does not have a volcanic nature and is made up of three main tectonostratigraphic sequences : i) Australia Affinity Sequence, that comprises units whose ages range from the Upper Carboniferous to the Late Miocene, deposited on Australian continental or transitional continental crust prior to collision with the Banda Terrane; ii) Banda Arc Terrane Sequence, that comprises the allochthonous forearc units of the Banda volcanic arc and are of Asia affinity. They span from Jurassic to Pliocene in age; iii) Banda Orogen Sequence, consisting of units that have formed or been deposited since the start of collision of the continental margin with the Banda forearc, ages spanning from upper Miocene to present.

The Manamas Mountain is an elevated region located in the northeast sector of the Timor-Leste Oecusse enclave, largely built up of volcanic rocks of Late Miocene age (Manamas Formation; Banda Arc Terrane Sequence). It may represent a fragment of the Banda Arc overthrusting on the northernmost edge of the Australian continental margin.

Recognition of the main structural lineament systems of the Manamas Mountain and definition of its main morphostructural characteristics to complement structural and geological mapping are the main goals of the present study, which aims to determine such aspects through interpretation of spatial remote detection digital data acquired by the Landsat satellite's sensor (ETMþ) and the Earth satellite's sensor (Aster) and aerial orthophoto maps.

How to cite: Lopes, F. C., Pratas, J., and Vicente, V.: Morphostructural mapping of the Manamas Mountain, a Banda Arc fragment overthrusting on the Australian Continental Margin (Oecusse, Timor-Leste), 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-477, https://doi.org/10.5194/icg2022-477, 2022.

Aggelos-Leandros Vgenopoulos, Ioannis Koukouvelas, George D. Bathrellos, Konstantinos Nikolakopoulos, and Hariklia D. Skilodimou

Landslide occurrences are physical phenomena that occur worldwide and contribute to the evolution of Earth’s landscape. Their associated consequences can lead to the damage of both the natural and man-made environment. Glafkos Stream originates from the Panachaikon mountains and draining into the Gulf of Patras. It flows from Southeast to Northwest in the Northwest Peloponnesus. This area is considered among the most active tectonic region of the world characterized by significant uplift over the recent period. Moreover, landslide events have occurred many times in this area and have repeatedly caused serious damage at sections of the settlements and at the road network.

The scope of the present study is to examine the landslides across the Glafkos Stream. A number of 34 landslides were studied. The causative and triggering parameters of landslides, the landslides repeatability and reactivation were examined. Additionally, the relation between landslides and faults were studied.

How to cite: Vgenopoulos, A.-L., Koukouvelas, I., Bathrellos, G. D., Nikolakopoulos, K., and Skilodimou, H. D.: Mass wasting processes within the Glafkos gorge, Achaia, Western Greece, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-546, https://doi.org/10.5194/icg2022-546, 2022.

Hariklia D. Skilodimou, George Bathrellos, Vasileios Antoniou, Ioannis Koukouvelas, and Konstantinos Nikolakopoulos

Geologic, tectonic, geomorphic conditions of a mountainous environment along with precipitation and human activities influence landslide occurrences. In many cases, their relation to landslide events is not well defined. The scope of the present study is to identify the influence of physical and anthropogenic factors in landslide activity. The study area is a mountainous part of northern Peloponnesus in southern Greece. It is located on the eastern part of the Gulf of Corinth and is considered as one of the most active tectonic rifts of the world.

The existing landslides, lithology, tectonic elements, slope angle, rainfall, road network along with land use of the study area was taken into consideration. Each physical and anthropogenic factor was further divided into sub-categories. Statistical approaches based on the observed relationship between each factor and the spatial distribution of landslides is very useful to reveal the correlation between landslide locations and factor.

Statistical analysis of landslide frequency and density was applied while frequency and density ratios were calculated. This analysis was further combined with Geographical Information Systems to evaluate the collected data and determine the association relation of physical and anthropogenic factors with landslide activity.

How to cite: Skilodimou, H. D., Bathrellos, G., Antoniou, V., Koukouvelas, I., and Nikolakopoulos, K.: A GIS-based study of factors related to landslides events in a tectonic active area, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-555, https://doi.org/10.5194/icg2022-555, 2022.

Georgios Pappas, Ioannis Koukouvelas, Konstantinos Nikolakopoulos, Efthymios Sokos, George D. Bathrellos, and Aggeliki Kyriou

On 17th November 2015, a strong earthquake affected the southern part of the Lefkada Island, Greece. After the earthquake extensive translational debris slides triggered cross most of west coast of the island in a distance of about 15 km. The majority of these slides concentrated at Egremni beach which is a famous touristic destination. The cliff is crossed by the Cephalonia Fault Zone and this is considered as a major factor provoking the steep slope, large-scale co-seismic and post-seismic mass wasting and disturbance of the forest of the cliff. Seven years after the 2015 event, the cliff remains at retreat due to limited forestation, seismicity and storms in the area. Monitoring of the cliff was performed between 2015 and 2021 including extensive field measurements, unmanned aerial vehicle (UAV) flight campaigns and a sediment trap. The high-resolution images acquired by the UAV were used for the creation of orthophoto maps and digital surface models (DSMs) of the cliff. The data indicates that Egremni cliff is slowly entering a stage of equilibrium due to climatic forcing, alongside minor seismicity and absence of forestation. Mass-wasting processes remained significant across the Lefkada west coast seven years after the 2015 earthquake sequence.

How to cite: Pappas, G., Koukouvelas, I., Nikolakopoulos, K., Sokos, E., Bathrellos, G. D., and Kyriou, A.: Tectonic evolution and mass wasting within the Lefkada west coast, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-570, https://doi.org/10.5194/icg2022-570, 2022.

Helen Machado, Fernando Villela, Marcos Pinheiro, and Paola Cianfarra

Many researchers have inferred that the genesis and formation of fluvial features at the mouth of the Amazon River (North Brazil) are related only to the sea level changes occurred in the Quaternary. In addition, there are still few works that take into account the possible influence of Neotectonics on the formation of these features, such as in the Breves-Boiuçu delta, located close to the Marajó Island, at the mouth of the Amazon River. This delta formed during the marine regression occurred around 5000 years BP, which caused silting of important rivers within the current delta feature. However, possible relations between the delta genesis and tectonic structures that have been reactivated since Miocene, as the Gurupá Arch, are still under debate. In this sense, the objective of this work is to evaluate the possible neotectonic influences on the formation of the Breves-Boiuçu delta. In order to achieve this objective, semi-automatic detection of structural lineaments was performed. Following the classical paradigm of Donald Wise, we have considered that the trend of the principal lineament domain corresponds to the main horizontal crustal stress (Shmax). Such lineaments were identified on pre-processed Shuttle Radar Topography Mission (SRTM) data, by means of the software SID3. These information were cumulated in databases and statistically analyzed by Daisy 3 software (https://host.uniroma3.it/progetti/fralab/Downloads/Daisy_Program/). In addition, drainage anomalies were mapped, considering that they are indicative of tectonic control on the river network. Finally, the possible size variation of the delta in the last 30 years was analyzed, evaluating its progradation rate through satellite images (Landsat 7 and Sentinel2). The results of the analysis of the lineament domains for the regional and local scale point to two possible tectonic models, in which it is possible to recognize the subsidiary fractures and shear fractures associated to a main regional strike-slip (R-Riedel shears, T-tension fractures, Y and X –shear fractures). According to the first model, dextral shear corridor E-W trending characterizes the investigated area with Shmax NW-SE oriented. Normal faults, joints, and T fractures follow this last orientation, whereas the structures E-W and N-S mapped correspond to, respectively, Y (dextral) and X (sinistral) faults. In the second model, a dextral shear zone NE-SW orientated exists, and E-W structures correspond to T fractures, whereas the N-S structures are dextral P faults. Regarding the drainage network analysis, several tectonic indicators were identified, such as: rectilinear drainages, elbows, and paleo-channels. Further studies are necessary to understand which tectonic model better characterizes the region, as well as the influence of neotectonic activity on the evolution of the deltaic landscape.

How to cite: Machado, H., Villela, F., Pinheiro, M., and Cianfarra, P.: Neotectonic influence on a delta landscape genesis downstream the Amazon River – North Brazil, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-376, https://doi.org/10.5194/icg2022-376, 2022.

Dimitrios Panagiotopoulos, Ioannis Koukouvelas, Konstantinos Nikolakopoulos, Dimitrios Papoulis, Paraskevi Lampropoulou, and George D. Bathrellos

Beachrocks are generally mapped on the coastline surface up to low depth in thesubtidal zone of sandy costs. These are commonly related with notches in nearby rocky beaches since both beachrocks and notches are correlated with active deformation and sea level fluctuation. As a study area we selected the Epirus coast, in Greece, where beachrocks outcrops and notches have not previously been studied. In this work, we used Unmanned Aerial Vehicles (UAVs), GNSS, Geographical Information System (GIS) and field work, to map beachrocks and notches in the broader area. All along this area it is observed active deformation and uplift. The uplift is correlated with the northeastern most tip of the Kephalonia Transform Fault and the existence of evaporitic domes along the coast. UAV mapping of these beachrock areas indicated that their width is 60 m to 80 m across the coast while at the same time we mapped many notches in nearby rocky coasts. The current study tries to investigate the correlation between the geotectonic setting of the broader area and the beachrock formations.

How to cite: Panagiotopoulos, D., Koukouvelas, I., Nikolakopoulos, K., Papoulis, D., Lampropoulou, P., and Bathrellos, G. D.: Beachrock and wave cut notches formation across the Epirus coast, NW Greece, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-573, https://doi.org/10.5194/icg2022-573, 2022.