<div> <div> <div> <p>Up to now, the compl... more <div> <div> <div> <p>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.</p> <p>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.</p> <p>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.</p> </div> </div> </div>
<p>Continental collisional zone may include high-standing plateaus, both internally... more <p>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.</p><p>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.</p>
In active tectonic regions, the topography is a primary reflection of the interaction of tectoni... more In active tectonic regions, the topography is a primary reflection of the interaction of tectonics and surf ace processes. We characterize tectonic processes through geomorphic investigations in the northem portion of Sila Massif (Calabria, Italy), that has been affected by both crustal extension since the early Pliocene and regional, rapid surface and rock uplift in the Pleistocene. Our study focuses on river long profiles and related relief metrics. Tue results are consistent with a landscape adjusting to both the influence of local fault offset as well as regional base level fall. In particular, along the northem flank of Sila, our analysis identifies an anomalously high-relief region (the OD-ridge) bound by extensional faults. This ridge has induced changes in the drainages, locally retarding headward extension of channels into this part of the plateau, which helps preserve the Sila upland as a relict landscape reflecting the prevailing tectonic and climatic setting prior to...
Geo-trekking in Ethiopia’s Tropical Mountains, 2019
The Dogu’a Tembien Massif is located on the western margin of the Mekelle Outlier, a nearly circu... more The Dogu’a Tembien Massif is located on the western margin of the Mekelle Outlier, a nearly circular mountainous area (8000 km2) with elevations ranging between 1200 and 2850 m (Fig. 2.1a).
Continental rift systems form by propagation of isolated rift segments that interact, and eventua... more Continental rift systems form by propagation of isolated rift segments that interact, and eventually evolve into continuous zones of deformation. This process impacts many aspects of rifting including rift morphology at breakup, and eventual ocean-ridge segmentation. Yet, rift segment growth and interaction remain enigmatic. Here we present geological data from the poorly documented Ririba rift (South Ethiopia) that reveals how two major sectors of the East African rift, the Kenyan and Ethiopian rifts, interact. We show that the Ririba rift formed from the southward propagation of the Ethiopian rift during the Pliocene but this propagation was short-lived and aborted close to the Pliocene-Pleistocene boundary. Seismicity data support the abandonment of laterally offset, overlapping tips of the Ethiopian and Kenyan rifts. Integration with new numerical models indicates that rift abandonment resulted from progressive focusing of the tectonic and magmatic activity into an oblique, thro...
The morphology of river channels results from the genetic and dynamic characteristics imposed by ... more The morphology of river channels results from the genetic and dynamic characteristics imposed by internal and external morphogenetic forcings. We studied reaches of river courses cutting across the contact area between the Romanian Plain (Carpathians foredeep) and the Curvature Subcarpathians, where active faults are located. In this area a wide monocline of tilted foredeep deposits generated a glacis-like macro-landform at the mountain front that connects the Subcarpathians with the Romanian Plain. The headwaters of studied rivers are located in the Subcarpathians (Cricovul Dulce River) and in the Carpathians (Prahova, Buzău and Milcov rivers). More in detail, we investigated river channels in plan view by morphometric and multi-temporal air-photo analysis to define the general trends of channel evolution. The results of this study indicate a spatial and temporal variability in the intensity of fluvial dynamic processes. The braided courses crossing the Subcarpathians and the piedm...
<div> <div> <div> <p>Up to now, the compl... more <div> <div> <div> <p>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.</p> <p>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.</p> <p>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.</p> </div> </div> </div>
<p>Continental collisional zone may include high-standing plateaus, both internally... more <p>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.</p><p>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.</p>
In active tectonic regions, the topography is a primary reflection of the interaction of tectoni... more In active tectonic regions, the topography is a primary reflection of the interaction of tectonics and surf ace processes. We characterize tectonic processes through geomorphic investigations in the northem portion of Sila Massif (Calabria, Italy), that has been affected by both crustal extension since the early Pliocene and regional, rapid surface and rock uplift in the Pleistocene. Our study focuses on river long profiles and related relief metrics. Tue results are consistent with a landscape adjusting to both the influence of local fault offset as well as regional base level fall. In particular, along the northem flank of Sila, our analysis identifies an anomalously high-relief region (the OD-ridge) bound by extensional faults. This ridge has induced changes in the drainages, locally retarding headward extension of channels into this part of the plateau, which helps preserve the Sila upland as a relict landscape reflecting the prevailing tectonic and climatic setting prior to...
Geo-trekking in Ethiopia’s Tropical Mountains, 2019
The Dogu’a Tembien Massif is located on the western margin of the Mekelle Outlier, a nearly circu... more The Dogu’a Tembien Massif is located on the western margin of the Mekelle Outlier, a nearly circular mountainous area (8000 km2) with elevations ranging between 1200 and 2850 m (Fig. 2.1a).
Continental rift systems form by propagation of isolated rift segments that interact, and eventua... more Continental rift systems form by propagation of isolated rift segments that interact, and eventually evolve into continuous zones of deformation. This process impacts many aspects of rifting including rift morphology at breakup, and eventual ocean-ridge segmentation. Yet, rift segment growth and interaction remain enigmatic. Here we present geological data from the poorly documented Ririba rift (South Ethiopia) that reveals how two major sectors of the East African rift, the Kenyan and Ethiopian rifts, interact. We show that the Ririba rift formed from the southward propagation of the Ethiopian rift during the Pliocene but this propagation was short-lived and aborted close to the Pliocene-Pleistocene boundary. Seismicity data support the abandonment of laterally offset, overlapping tips of the Ethiopian and Kenyan rifts. Integration with new numerical models indicates that rift abandonment resulted from progressive focusing of the tectonic and magmatic activity into an oblique, thro...
The morphology of river channels results from the genetic and dynamic characteristics imposed by ... more The morphology of river channels results from the genetic and dynamic characteristics imposed by internal and external morphogenetic forcings. We studied reaches of river courses cutting across the contact area between the Romanian Plain (Carpathians foredeep) and the Curvature Subcarpathians, where active faults are located. In this area a wide monocline of tilted foredeep deposits generated a glacis-like macro-landform at the mountain front that connects the Subcarpathians with the Romanian Plain. The headwaters of studied rivers are located in the Subcarpathians (Cricovul Dulce River) and in the Carpathians (Prahova, Buzău and Milcov rivers). More in detail, we investigated river channels in plan view by morphometric and multi-temporal air-photo analysis to define the general trends of channel evolution. The results of this study indicate a spatial and temporal variability in the intensity of fluvial dynamic processes. The braided courses crossing the Subcarpathians and the piedm...
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