Krzysztof Gaidzik

<p>The western flank of the Central Andes shows a high concentration of giant landslides (Strasser and Schlunegger, 2005; Audin & Bechir 2006; Pinto et al., 2008; Matther et al., 2014; Crosta et al., 2014, Margirier et al., 2015; Zerathe et al., 2017; Delgado et al., 2020) related to specific characteristics such as a strong local relief (canyons, structural-flexures, etc.), strong and recurrent seismo-tectonic activities, and atypical climate combining long-term hyper-aridity and punctual extreme precipitation events. In this context, ongoing studies inventorying more than one-thousand giant paleo-landslides in this region underline their spatial clustering that is controlled by coupled conditioning factors including high topographical gradients and specific lithology (Delgado et al., 2020).</p><p>The purpose of this study is to constrain now the kinematics of landsliding and ultimately to get time-frequency law of the gravitational slope destabilizations of this Andean region. For this, we focus on the Locumba valley (south Peru) where more than 30 giant landslides are clustered and distributed in two main typologies (rockslide and rock-avalanche). We applied cosmogenic nuclide dating to 8 paleo-landslides, sampling 52 boulders. We used alternatively <sup>10</sup>Be/quartz or <sup>10</sup>Be/feldspar depending on the available lithology.</p><p>Our dataset opens an unprecedented opportunity for paleolandslides studies and reconstructions. Indeed, the exposure-ages obtained range from the Holocene to the Pleistocene, the oldest ages reaching one-million years. This new temporal-scale allows to address and discuss triggering processes in the context of seismo-tectonic activities and Quaternary climate changes. Exposure-ages distribution shows several time-frequency peaks suggesting that gravitational destabilizations are episodic phenomena with time recurrence on the range of ~100 ka. Additionally, our time-constraints indicate that most of the current landscapes along this Western Andean flank are older than one-million years. Especially, fluvial incision and valley deepening processes are currently very low as testified by relicts of landslide dams and associated lacustrine sediments of hundred’s thousand years old that are preserved along the main canyons and still not fully re-incised.</p>

The Ngorongoro Crater is the largest unflooded and not destroyed collapse volcanic caldera of the shield volcano on Earth. It attracts many visitors each year not only because of the undoubted -wealth of the -wildlife and breathtaking views, but also due to the geotouristic attractiveness of this definite location. The Crater is in fact a specific example of geological processes, relevant to the development of planet Earth. In a relatively small area one can observe rocks of different types and ages: Precambrian igneous and metamorphic rocks, -volcanic rocks formed in the Pliocene, Pleistocene, and even nowadays, as -well as sedimentary rocks, up to those currently forming -within the caldera floor. The origin and development of the Ngorongoro -volcano, and lately caldera, is closely related to the activity of rifting processes occurring along the Gregory Rift, belonging to the East African Rift System. It represents one of the three arms of the Afar triple junction associated -with...

Abstract The Peruvian subduction zone is prone to destructive megathrust earthquakes that rupture plate interface, often associated with devastating tsunamis, and usually smaller crustal earthquakes in the overriding plate that, due to the shallow focal depth and proximity to the human settlements, can be equally hazardous. However, these latter ones are generally less studied and often not included in the seismic hazard assessments. Thus, in this study, we used the Seismo-Lineament Analysis Method (SLAM) to explore potentially active structures on the overriding plate above the Nazca subduction zone in the Southern Peruvian Andes, which according to the current crustal seismicity, might have hosted ruptures in the past. Moreover, we computed their possible seismogenic potential, assuming the worst-case scenario, and discussed the tectonic implications and likely sources of stress that might trigger earthquakes along these faults. For that, we combined the focal mechanism data and obtained seismo-lineaments with the results of the morpho-tectonic analysis of the digital elevation models and satellite images. The principally W- to NW-striking seismo-lineaments identified in the study area that could represent the surface expressions of potentially seismogenic faults, in general, agree with the previously reported shallow crustal active fault systems in the Southern Peruvian Andes. The applied scaling relationships suggest a seismic potential for earthquakes of maximum moment magnitudes up to 7.3–7.4 for the recorded structures. Collected data indicates an extensional regime in the upper crust of the South American plate above the Nazca subduction, with the horizontal extension perpendicular to the trench axis. The reactivation of identified structures can be related to the following sources of stress: 1) strain partitioning in the oblique subduction zone, 2) crustal seismicity induced by megathrust earthquakes, 3) extension in the most upper part of the uplifting area above the subducting slab, and 4) volcanic activity. Our findings highlight the usefulness of the SLAM technique as a tool to recognize prone areas for potential seismogenic faults that should be studied in greater detail using paleoseismological, geomorphological, geodetic, and geophysical methods. These also show the importance of crustal faults in the overall seismic hazard assessments.

Uplift is the predominant factor controlling fluvial systems in tectonically deforming regions. Mountains along subduction zones force incision, aggradation, or sinuosity modifications, showing differential uplift and variations in erosion rates, in river incision, and in channel gradient produced by ongoing tectonic deformation. Thus, landscape can provide information on the tectonic activity of a defined region. Here, field studies, analysis of geomorphic indices using a digital elevation model, and dating of river terraces were undertaken to extract the following: (1) determine rates of ongoing tectonic deformation, (2) identify evidence of active faulting, and (3) explain the possible relation of ongoing differential uplift in the topography of the overriding plate with the geometry and roughness effects of subducting slab along the Mexican subduction within the Guerrero sector. Landscape analysis using geomorphic indices suggests segmentation along stream of the studied Tecpan ...

A spectacular epigenetic silicification was encountered in the Oxfordian bedded limestones exposed in the Sokole Hills situated in the Krakow-Częstochowa Upland. The main epigenetic mineral is microcrystalline quartz accompanied by minor goethite, hematite, barite, galena and sphalerite. Locally, the mineralized limestones reveal Pb and Cu contents exceeding over 150 times the background values of these metals in unmineralized limestones.The epigenetic mineralization of the bedded limestones was probably a two-stage process. During the first, Early Cretaceous stage, silicified limestones formed at the erosional surface of a denuded carbonate complex. Such silicification greatly limited the progress of the first karstification phase of the Upper Jurassic carbonates initiated in the Hauterivian. The sources of silica accumulated in the limestones were descending solutions enriched in silica derived from the weathering zone. This silicification affected the topmost part of the Upper Ju...

Jerzy ̄ABA, Zbigniew MA£OLEPSZY, Krzysztof GAIDZIK, Justyna CIESIELCZUK & Andrzej PAULO 1 De part ment of Fun da men tal Ge ol ogy, Fac ulty of Earth Sci ences, Uni ver sity of Silesia, Bêdziñska 60, 41-200 Sosnowiec, Poland, jerzy.zaba@gmail.com; malol@us.edu.pl; k.gaidzik@gmail.com; justyna.ciesielczuk@us.edu.pl 2 Fac ulty of Ge ol ogy, Geo phys ics and En vi ron ment Pro tec tion, AGH Uni ver sity of Sci ence and Tech nol ogy, Mickiewicza 30, 30-059 Kraków, Poland, paulo@geol.agh.edu.pl

Comparison of fold deformation sequences in the northern and southern metamorphic cover of the Karkonosze granitoids. A b s t r a c t. We applied the detailed structural analysis to 394 outcrops in the southern and northern metamorphic cover of the Karkonosze Intrusion. We recognised five generations of fold structures: F 1 – poorly preserved tight intrafoliation folds; F 2 – the most common generation, with the whole variety of fold geometries, W–E and WSW–ENE-oriented fold axes in the northern contact zone, and W–E and WNW–ESE-oriented fold axes in the southern contact zone; F 3 – chevron folds; F 4 – kink folds observed only in the Stara Kamienica schist belt; and F5–wide open folds, locally transformed into monoclinal kink folds, probably formed during the Variscan intrusion of the Karkonosze pluton. Similarity observed in the structural style in the northern and southern contact zones prove that these lithostratigraphic units had formed a single unit – the Izera-Kowary Unit – a...

Trabajo presentado en el 8th International Symposium on Andean Geodynamics (ISAG)", realizado en Quito-Ecuador, del 24-26 setiembre, 2019. Evento organizado por el Instituto Geofisico, Escuela Politecnica Nacional (IG-EPN) del Ecuador, y el French Institut de Recherche pour le Developpement (IRD).

The Danube Bend is the site of the proposed Nagymaros dam, part of the Gabčikovo–Nagymaros hydropower complex in Slovakia and Hungary. The dam was designed in the 1970s to resist intensity VI seismic events. We present historical and archaeological evidence for an intensity IX earthquake on 21 August 1541, which destroyed buildings of the royal town of Visegrád. Evidence includes vertical fissures cutting through the 30-m-high, thirteenth-century donjon Salamon Tower, built on hard rock. Some parts of the adjacent fifteenth-century Franciscan friary, built on the alluvial plain, collapsed because of liquefaction of the subsoil. The date of a potentially responsible earthquake on 21 August 1541 was recorded in a sermon of the eyewitness Lutheran minister Péter Bornemisza, living at Pest-Buda, 35 km away. Taken by the Ottoman army in 1544, the royal town and the fortress lost strategic importance, never to be rebuilt. Photographs and drawings of the donjon made three centuries later f...

New estimates of long-term velocities of permanent GPS stations in Southern Mexico reveal that the geologically discernible ∼650-km long shear zone, which strikes parallel to the Middle America trench, is active. This left-lateral strike-slip, La Venta–Chacalapa (LVC) fault system, is apparently associated with a motion of the Xolapa terrain and at the present time is the northern boundary of a ∼110–160-km wide forearc sliver with a sinistral motion of 3–6 mm/year with respect to the North America plate. This sliver is the major tectonic feature in the Guerrero and Oaxaca regions, which accommodates most of the oblique component of the convergence between the Cocos and North America plates. Previous studies based purely on the moment tensor coseismic slips exceedingly overestimated the sliver inland extent and allocated its northern margin on or to the north of the Trans-Mexican Volcanic Belt. While the LVC fault system probably slips slowly over geologic scale time and there is not any historic evidence of large earthquakes on the fault so far, its seismic potential could be very high, assuming a feasible order of ∼103 years recurrence cycle. A detailed analysis of long-term position time series of permanent GPS stations in the Guerrero and Oaxaca states, Southern Mexico discards previous models and provides clear evidence of an active LVC fault zone bounding the Xolapa forearc sliver. The southeastward motion of this sliver may have persisted for the last ∼8–10 Million year and played an important role in the tectonic evolution of the region.

Tec tonic re search and mor pho log i cal ob ser va tions were car ried out in six caves (Kalacka, Goryczkowa, Kasprowa Ni¿na, Kasprowa OErednia, Kasprowa Wy¿nia and Magurska) in the Bystra Val ley, in the Tatra Moun - tains. There are three cave lev els, with the youn gest ac tive and the other two in ac tive, re flect ing de vel op ment partly un der epiphreatic and partly un der phreatic con di tions. These stud ies dem on strate strong con trol of the cave pat tern by tec tonic fea tures, in clud ing faults and re lated frac tures that orig i nated or were re ju ve nated dur ing up lift, last ing from the Late Mio cene. In a few lo cal cases, the cave pas sages are guided by the com bined in flu ence of bed ding, joints and frac tures in the hinge zone of a chev ron anticline. That these cave pas sages are guided by tec tonic struc tures, ir re spec tive of lithological dif fer ences, in di cates that these proto-con duits were formed by “tec tonic in cep tion”. Dif fer ences in...

Landslide detection and susceptibility mapping are crucial in risk management and urban planning. Constant advance in digital elevation models accuracy and availability, the prospect of automatic landslide detection, together with variable processing techniques, stress the need to assess the effect of differences in input data on the landslide susceptibility maps accuracy. The main goal of this study is to evaluate the influence of variations in input data on landslide susceptibility mapping using a logistic regression approach. We produced 32 models that differ in (1) type of landslide inventory (manual or automatic), (2) spatial resolution of the topographic input data, (3) number of landslide-causing factors, and (4) sampling technique. We showed that models based on automatic landslide inventory present comparable overall prediction accuracy as those produced using manually detected features. We also demonstrated that finer resolution of topographic data leads to more accurate a...

Inherited tectonic structures, ongoing tectonic deformation, and variations in relative rock uplift rates play an important role in conditioning the processes of relief development. Their influence among other factors, such as climate and lithology, can be quantified using landscape analysis, and geomorphometric indices, in particular. The usage of landscape analysis in recent years is increasing systematically due to the constant improvement of the digital elevation models and GIS software that significantly facilitate this approach. In this study, we aim to recognize the influence of tectonic structures and processes on relief development in the low mountains with moderate relief of the Soła River catchment in the Western Outer Carpathians. To this end, we calculated geomorphometric indices (river longitudinal profile, stream-length gradient index, minimum bulk erosion, relief ratio, circulatory ratio, elongation ratio, and hypsometric integral) for the Sola River and its 47 sub-c...

<p>The Nile is the longest river on earth, accordingly with huge drainage and major floods, regulated by the African monsoon. Significant amount of sediment is carried by the river; its deposition forms alluvial plains along most of its course. However, in Upper Egypt and northern Sudan there are six major and several minor cataracts totalling 327 km in length. There the river flows directly on bedrock, and a multitude of islands and rocks in the riverbed makes navigation hard or impossible throughout much of the year. Obviously, the Nile is unable to remove these obstacles from its flow (despite its ability to carve a deep canyon in the African continent during Messinian lowstand of the Mediterranean Sea). It has been suggested that the Cataract Nile is in a youthful stage, flows along structurally controlled turns and that earthquakes in southern Egypt prove that portions of the Nubian Swell are still tectonically active (Thurmond et al., 2004). However, the Sudan part of the river does not show any seismic activity. An archaeoseismological study is in progress to locate evidence of past earthquakes preserved in monumental architecture erected during the past 3500 years. Pyramids in Meroe display masonry shifted in plane of the wall: this was caused by one or more earthquakes of intensity I<sub>0</sub> = 9 on the Archaeological Intensity Scale. We suggest that an ongoing systematic study of monumental stone and adobe buildings along the Nile in the region of the Nubian Swell will find further evidence of major earthquakes in the region, contributing to a better understanding of seismic hazard in Sudan.</p><p>Reference</p><p>Thurmond, A.K., Stern, R.J., Abselsalam, M.G., Nielsen, K.C., Abdeen, M.M., Hinz, E. (2004): The Nubian Swell. - Journal of African Earth Sciences 39, 401-407.</p>

Extreme storms commonly trigger landslides in regions of humid, warm tropical climate causing loss of life and economic devastation. The tropical mountainous areas of Guerrero in southwest Mexico are frequently hit by extreme hurricanes and cyclones and thus prone to landslides. On 16 September 2013, a huge landslide resulted in 71 fatalities and destroyed a large part of La Pintada Village. We applied remote sensing techniques using the LIDAR DEM and high-resolution images of the La Pintada area, a post-landslide field survey, geotechnical laboratory tests of colluvium material from the landslide, and a slope stability analysis. We also interviewed eyewitnesses accounts of the event. Our results suggest that the 2013 La Pintada landslide was a complex and two-stage event. An intense four-day-long rainfall event related to the landfall of Hurricane Manuel resulted in the oversatu-ration of soil, which was the main factor that caused the landslide. The effect of rainfall was amplified by the lack of high and dense vegetation on the 250-m-high slope. The lack of vegetation and slope-undercutting likely contributed to the decreased slope stability. We suggest that increased intensity of extreme storms has contributed to increased landslides in this area. Furthermore, in tropical climate areas, where significant population lives in mostly developing countries, the combination of these phenomena makes them highly vulnerable to extreme storms and landslide hazards.