KINEMATIČKI MODEL SPOROGA KLIZIŠTA KOSTANJEK (GRAD ZAGREB, HRVATSKA)

The interpretation of landslide kinematics provides important information for those responsible for the management of landslide risk. This paper presents an interpretation of the kinematics of the slow-moving Kostanjek landslide, located in the urbanized area of the city of Zagreb, Croatia. The sliding material (very weak to weak marls, often covered with clayey topsoil) exhibits plastic, rather than rigid behavior. Due to this reason, and low landslide velocities, landslide features, such as main scarps or lateral flanks, are barely noticeable or do not exist in most of the landslide area. The data used for the kinematic interpretation were obtained from 15 GNSS sensors, for the period of 2013-2019. The monitoring data revealed a different spatial and temporal distribution of landslide velocities, resulting as a consequence of geomorphological conditions and forces that govern the landslide movements. Temporally, eight periods of faster movements and seven periods of slower movements were determined. Spatially, velocities measured in the central part of the landslide were higher than on its boundaries. The interpretation of the surface (horizontal and vertical) displacements and the direction of movement reveal a new insight into the engineering geological model and provide important information for the management of the Kostanjek landslide risk.Interpretacija kinematičkoga modela klizišta važan je podatak pri procjeni ugroženosti za stanovnike, građevine i infrastrukturu na području klizišta. Ovaj članak opisuje interpretaciju kinematičkoga modela sporoga klizišta Kostanjek, koje se nalazi u gradu Zagrebu. Materijali u klizanju (vrlo slabi do slabi lapori, često prekriveni glinovitim pokrivačem) uglavnom pokazuju plastično ponašanje. Zbog toga, a i zbog male brzine klizišta, dijelovi klizišta kao što su glavna pukotina ili bokovi klizišta izostaju ili nisu jasno izraženi na površini terena. Podatci korišteni za interpretaciju kinematičkoga modela prikupljeni su s 15 GNSS uređaja, u razdoblju između 2013. i 2019. godine. Podatci praćenja upućuju na različitu prostornu i vremensku raspodjelu brzina, koja je posljedica geomorfoloških uvjeta te sila koje uzrokuju gibanje klizišta. Vremenski je moguće raspoznati osam razdoblja bržega gibanja i sedam razdoblja sporijega gibanja, dok su prostorno veće brzine izmjerene u središnjemu dijelu klizišta nego na njegovim rubovima. Rezultati interpretacije horizontalnih i vertikalnih pomaka te smjerova gibanja upućuju na novi inženjerskogeološki model klizišta te pružaju važne podatke za prostorno planiranje i civilnu zaštitu

Quantitative rockfall susceptibility assessment by integrating kinematic and statistical analyses : doctoral dissertation

U doktorskom radu prikazani su rezultati istraživanja čija je svrha bila razvoj nove metode za kvantitativnu procjenu podložnosti stijenskih kosina odronima u detaljnom mjerilu primjenom daljinskih istraživanja. Metoda je razvijana na četiri pilot područja izgrađenim od karbonatnih i klastičnih naslaga: stijenske kosine iznad grada Omiša, stijenske kosine Brljan u Nacionalnom parku Krka te stijenski zasjeci Špičunak i Lokve u Groskom kotaru. 3D digitalni modeli stijenskih kosina pilot područja, visoke preciznosti i razlučivosti, izrađeni su na osnovi terestričkog laserskog skeniranja i snimanjem iz zraka pomoću bespilotne letjelice. Analizom digitalnih modela pilot područja identificirane su i određene značajke stijenske mase (stupanj trošnosti i vrsta stijene) i geometrijske značajke diskontinuiteta (orijentacija i setovi diskontinuiteta, razmak i postojanost diskontinuiteta) ručnim, polu-automatiziranim i automatiziranim metodama i tehnikama. Na osnovi rezultata analiziranih podataka izdvojene su kvazi-homogene inženjerskogeološke zone koje su zajedno s pripadajućim podacima o značajkama stijenske mase i geometrijskim značajkama diskontinuiteta predstavljale ulazne podatke za procjenu podložnosti stijenskih kosina odronima. Podložnost stijenskih kosina odronima kvantificirana je s obzirom na indeksne pokazatelje podložnosti planarnom, klinastom i slomu prevrtanjem te indeksom podložnosti stijenskih kosina odronima. Navedeni indeksni pokazatelji računati su za svaku ćeliju digitalnih modela istraživanih stijenskih kosina na temelju analiza vjerojatnosti pojave diskontinuiteta ili presječnica diskontinuiteta na određenom dijelu stijenske kosine, prostornih kinematičkih analiza i vrijednosti modificiranog kinematičkog indeksa hazarda. Cijeli proračun u potpunosti je automatiziran pomoću razvijenog algoritma ROCKS. Modeli podložnosti stijenskih kosina odronima za pilot područja izrađeni su interpolacijom vrijednosti indeksnih pokazatelja na digitalnim modelima površina stijenskih kosina. Verifikacijom modela podložnosti utvrđeno je da visoke vrijednosti podložnosti ukazuju na potencijalno nestabilne stijenske blokove, nepovoljno orijentirane diskontinuitete, a zone veće gustoće visokih vrijednosti indeksnih pokazatelja ukazuju na prioritetna područja prilikom ublažavanja hazarda i rizika od odrona. Metoda za kvantitativnu procjenu stijenskih kosina odronima može se primjenjivati u inženjerskogeološkim i geotehničkim istraživanjima stijenskih kosina, u inženjerskim projektima sanacije i zaštite stijenskih kosina te za mjere ublažavanja hazarda i rizika od odrona.The aim of this doctoral dissertation was to develop a method for quantitative rockfall susceptibility assessment at slope scale using techniques of remote sensing. For the development of this method 4 pilot areas were chosen, each with different structural-geological setting. These pilot areas are rock slopes above the town of Omiš, rock slopes and rock cuts Brljan in the Krka National Park, rock cuts Špičunak and Lokve in the Gorski kotar area. High-resolution and precision digital models of the investigated rock slopes were created based on terrestrial laser scanning and UAV based photogrammetry. Identification and mapping of the rock mass properties (degree of weathering and rock type) and the geometrical properties of the discontinuities (orientation and sets, spacing and trace length) was carried out by remote sensing on the digital models using manual, semi-automated and automated techniques and methods. Also, for the Lokve rock cut pilot area two different rock types were determined by semi-automated analysis of intensity data, derived from terrestrial laser scanner. Based on analysed rock mass and discontinuity data, pilot areas were divided into 65 quasi-homogenic engineering geological zones and each zone was associated with certain rock mass and discontinuity data that can be found in that zone. Engineering geological zones, along with rock mass and discontinuity properties, were used as input dana for quantitative rockfall susceptibility assessment. In order to quantify susceptibility, 4 susceptibility indices were developed: Plane Failure, Wedge Failure and Toppling Susceptibility Indices, from which Rockfall Susceptibility Index is derived based on the probability of union. Susceptibility indices were calculated for each 3D rock slope model cell based on the probability analysis, spatial kinematic analysis and modified Kinematic Hazard Index. This calculation processes were entirely automated by developed algorithm ROCKS in MATLAB programming platform. Rockfall susceptibility models were created by interpolation of the susceptibility indices on the digital rock slope models for each pilot area. In total 16 rockfall susceptibility models were created. Verification of the resulting rockfall susceptibility models has indicated that high values of Rockfall Susceptibility Index highlight potentially unstable rock blocks and unfavourably orientated discontinuities. Also, zones with higher density of high Rockfall Susceptibility Index values point out to certain quasi-homogenic engineering geological zones which should be priority in rockfall hazard and risk reduction by efficient design of rock slope protection measures. Developed method for quantitative rockfall susceptibility assessment has shown that it can be used in detailed engineering geological and geotechnical investigation of rock slopes, and rock slope remediation and protection assessments. Also, it represents a precise and valuable input data for rockfall hazard and risk assessment at the slope scale

Quantitative rockfall susceptibility assessment by integrating kinematic and statistical analyses : doctoral dissertation

U doktorskom radu prikazani su rezultati istraživanja čija je svrha bila razvoj nove metode za kvantitativnu procjenu podložnosti stijenskih kosina odronima u detaljnom mjerilu primjenom daljinskih istraživanja. Metoda je razvijana na četiri pilot područja izgrađenim od karbonatnih i klastičnih naslaga: stijenske kosine iznad grada Omiša, stijenske kosine Brljan u Nacionalnom parku Krka te stijenski zasjeci Špičunak i Lokve u Groskom kotaru. 3D digitalni modeli stijenskih kosina pilot područja, visoke preciznosti i razlučivosti, izrađeni su na osnovi terestričkog laserskog skeniranja i snimanjem iz zraka pomoću bespilotne letjelice. Analizom digitalnih modela pilot područja identificirane su i određene značajke stijenske mase (stupanj trošnosti i vrsta stijene) i geometrijske značajke diskontinuiteta (orijentacija i setovi diskontinuiteta, razmak i postojanost diskontinuiteta) ručnim, polu-automatiziranim i automatiziranim metodama i tehnikama. Na osnovi rezultata analiziranih podataka izdvojene su kvazi-homogene inženjerskogeološke zone koje su zajedno s pripadajućim podacima o značajkama stijenske mase i geometrijskim značajkama diskontinuiteta predstavljale ulazne podatke za procjenu podložnosti stijenskih kosina odronima. Podložnost stijenskih kosina odronima kvantificirana je s obzirom na indeksne pokazatelje podložnosti planarnom, klinastom i slomu prevrtanjem te indeksom podložnosti stijenskih kosina odronima. Navedeni indeksni pokazatelji računati su za svaku ćeliju digitalnih modela istraživanih stijenskih kosina na temelju analiza vjerojatnosti pojave diskontinuiteta ili presječnica diskontinuiteta na određenom dijelu stijenske kosine, prostornih kinematičkih analiza i vrijednosti modificiranog kinematičkog indeksa hazarda. Cijeli proračun u potpunosti je automatiziran pomoću razvijenog algoritma ROCKS. Modeli podložnosti stijenskih kosina odronima za pilot područja izrađeni su interpolacijom vrijednosti indeksnih pokazatelja na digitalnim modelima površina stijenskih kosina. Verifikacijom modela podložnosti utvrđeno je da visoke vrijednosti podložnosti ukazuju na potencijalno nestabilne stijenske blokove, nepovoljno orijentirane diskontinuitete, a zone veće gustoće visokih vrijednosti indeksnih pokazatelja ukazuju na prioritetna područja prilikom ublažavanja hazarda i rizika od odrona. Metoda za kvantitativnu procjenu stijenskih kosina odronima može se primjenjivati u inženjerskogeološkim i geotehničkim istraživanjima stijenskih kosina, u inženjerskim projektima sanacije i zaštite stijenskih kosina te za mjere ublažavanja hazarda i rizika od odrona.The aim of this doctoral dissertation was to develop a method for quantitative rockfall susceptibility assessment at slope scale using techniques of remote sensing. For the development of this method 4 pilot areas were chosen, each with different structural-geological setting. These pilot areas are rock slopes above the town of Omiš, rock slopes and rock cuts Brljan in the Krka National Park, rock cuts Špičunak and Lokve in the Gorski kotar area. High-resolution and precision digital models of the investigated rock slopes were created based on terrestrial laser scanning and UAV based photogrammetry. Identification and mapping of the rock mass properties (degree of weathering and rock type) and the geometrical properties of the discontinuities (orientation and sets, spacing and trace length) was carried out by remote sensing on the digital models using manual, semi-automated and automated techniques and methods. Also, for the Lokve rock cut pilot area two different rock types were determined by semi-automated analysis of intensity data, derived from terrestrial laser scanner. Based on analysed rock mass and discontinuity data, pilot areas were divided into 65 quasi-homogenic engineering geological zones and each zone was associated with certain rock mass and discontinuity data that can be found in that zone. Engineering geological zones, along with rock mass and discontinuity properties, were used as input dana for quantitative rockfall susceptibility assessment. In order to quantify susceptibility, 4 susceptibility indices were developed: Plane Failure, Wedge Failure and Toppling Susceptibility Indices, from which Rockfall Susceptibility Index is derived based on the probability of union. Susceptibility indices were calculated for each 3D rock slope model cell based on the probability analysis, spatial kinematic analysis and modified Kinematic Hazard Index. This calculation processes were entirely automated by developed algorithm ROCKS in MATLAB programming platform. Rockfall susceptibility models were created by interpolation of the susceptibility indices on the digital rock slope models for each pilot area. In total 16 rockfall susceptibility models were created. Verification of the resulting rockfall susceptibility models has indicated that high values of Rockfall Susceptibility Index highlight potentially unstable rock blocks and unfavourably orientated discontinuities. Also, zones with higher density of high Rockfall Susceptibility Index values point out to certain quasi-homogenic engineering geological zones which should be priority in rockfall hazard and risk reduction by efficient design of rock slope protection measures. Developed method for quantitative rockfall susceptibility assessment has shown that it can be used in detailed engineering geological and geotechnical investigation of rock slopes, and rock slope remediation and protection assessments. Also, it represents a precise and valuable input data for rockfall hazard and risk assessment at the slope scale

Geological mapping and reconstruction of geological setting of Skrad area in Gorski kotar : master’s thesis

Cilj ovog rada bio je istražiti geološku građu okolice Skrada na temelju površinskih geoloških podataka u mjerilu 1:20.000. Područje istraživanja izgrađuju naslage permske, trijaske i jurske starosti. Današnji strukturni odnosi između litostratigrafskih jedinica izuzetno su kompleksni, a uvjetovani su trima glavnim tektonskim fazama. Najstariju fazu obilježava navlačna tektonika kojom su alohtone naslage permske i trijaske starosti dovedene u strukturni položaj iznad autohtonih naslaga glavnog dolomita noričko–retske starosti te izmjene dolomita i vapnenaca donjo- i srednjejurske starosti. Nakon navlačne faze nastupila je faza ekstenzijske tektonike koja je razlomila navlaku, a ujedno i otkrila podinu navlake u tektonskom oknu u kanjonu potoka Jasle i Curak. Najmlađa tektonska faza obilježena je kompresijskom tektonikom koja je autohtoni noričko–retski dolomit dovela u strukturni položaj iznad donjojurskih karbonata. Uz geološku kartu u mjerilu 1:20.000 s pripadajućim profilima, načinjen je geološki 3D model i interaktivni GIS projekt koji pruža mogućnost dopune i korekcije podataka, kao i pregled svih podataka obuhvaćenih terenskim istraživanjima.Abstract: The goal of this thesis was to thoroughly investigate Skrad area based on surface data that were collected in the course of geological mapping in 1:20.000 scale. The research area is built out of clastic and carbonate deposits of Permian, Triassic and Jurassic age. The present-day structural relations between the litostratigraphic units are complex due to three tectonic phases. The oldest phase is characterised by thrust faulting that resulted in allochthonous (nappe) position of Permian and Triassic above autochthonous Triassic and Jurassic deposits. The second phase is characterised by extension accommodated by normal faulting, which resulted in breaking apart of the nappe contact and opening of tectonic window located in the canyon of Curak and Jasle streams. The last tectonic phase is characterised by reverse faulting which enabled uplift of the autochthonous Norian and Rethian Hauptdolomite in structural position above lower Jurassic carbonates. In this thesis, beside the geological map in 1:20.000 scale accompanied by geological cross-sections, the geological 3D model and interactive GIS project have been made, too. The latter provides a possibility to manipulate with collected data and also to incorporate new data from future studies

Geological mapping and reconstruction of geological setting of Skrad area in Gorski kotar : master’s thesis

Cilj ovog rada bio je istražiti geološku građu okolice Skrada na temelju površinskih geoloških podataka u mjerilu 1:20.000. Područje istraživanja izgrađuju naslage permske, trijaske i jurske starosti. Današnji strukturni odnosi između litostratigrafskih jedinica izuzetno su kompleksni, a uvjetovani su trima glavnim tektonskim fazama. Najstariju fazu obilježava navlačna tektonika kojom su alohtone naslage permske i trijaske starosti dovedene u strukturni položaj iznad autohtonih naslaga glavnog dolomita noričko–retske starosti te izmjene dolomita i vapnenaca donjo- i srednjejurske starosti. Nakon navlačne faze nastupila je faza ekstenzijske tektonike koja je razlomila navlaku, a ujedno i otkrila podinu navlake u tektonskom oknu u kanjonu potoka Jasle i Curak. Najmlađa tektonska faza obilježena je kompresijskom tektonikom koja je autohtoni noričko–retski dolomit dovela u strukturni položaj iznad donjojurskih karbonata. Uz geološku kartu u mjerilu 1:20.000 s pripadajućim profilima, načinjen je geološki 3D model i interaktivni GIS projekt koji pruža mogućnost dopune i korekcije podataka, kao i pregled svih podataka obuhvaćenih terenskim istraživanjima.Abstract: The goal of this thesis was to thoroughly investigate Skrad area based on surface data that were collected in the course of geological mapping in 1:20.000 scale. The research area is built out of clastic and carbonate deposits of Permian, Triassic and Jurassic age. The present-day structural relations between the litostratigraphic units are complex due to three tectonic phases. The oldest phase is characterised by thrust faulting that resulted in allochthonous (nappe) position of Permian and Triassic above autochthonous Triassic and Jurassic deposits. The second phase is characterised by extension accommodated by normal faulting, which resulted in breaking apart of the nappe contact and opening of tectonic window located in the canyon of Curak and Jasle streams. The last tectonic phase is characterised by reverse faulting which enabled uplift of the autochthonous Norian and Rethian Hauptdolomite in structural position above lower Jurassic carbonates. In this thesis, beside the geological map in 1:20.000 scale accompanied by geological cross-sections, the geological 3D model and interactive GIS project have been made, too. The latter provides a possibility to manipulate with collected data and also to incorporate new data from future studies

Geological mapping and reconstruction of geological setting of Skrad area in Gorski kotar : master’s thesis

Cilj ovog rada bio je istražiti geološku građu okolice Skrada na temelju površinskih geoloških podataka u mjerilu 1:20.000. Područje istraživanja izgrađuju naslage permske, trijaske i jurske starosti. Današnji strukturni odnosi između litostratigrafskih jedinica izuzetno su kompleksni, a uvjetovani su trima glavnim tektonskim fazama. Najstariju fazu obilježava navlačna tektonika kojom su alohtone naslage permske i trijaske starosti dovedene u strukturni položaj iznad autohtonih naslaga glavnog dolomita noričko–retske starosti te izmjene dolomita i vapnenaca donjo- i srednjejurske starosti. Nakon navlačne faze nastupila je faza ekstenzijske tektonike koja je razlomila navlaku, a ujedno i otkrila podinu navlake u tektonskom oknu u kanjonu potoka Jasle i Curak. Najmlađa tektonska faza obilježena je kompresijskom tektonikom koja je autohtoni noričko–retski dolomit dovela u strukturni položaj iznad donjojurskih karbonata. Uz geološku kartu u mjerilu 1:20.000 s pripadajućim profilima, načinjen je geološki 3D model i interaktivni GIS projekt koji pruža mogućnost dopune i korekcije podataka, kao i pregled svih podataka obuhvaćenih terenskim istraživanjima.Abstract: The goal of this thesis was to thoroughly investigate Skrad area based on surface data that were collected in the course of geological mapping in 1:20.000 scale. The research area is built out of clastic and carbonate deposits of Permian, Triassic and Jurassic age. The present-day structural relations between the litostratigraphic units are complex due to three tectonic phases. The oldest phase is characterised by thrust faulting that resulted in allochthonous (nappe) position of Permian and Triassic above autochthonous Triassic and Jurassic deposits. The second phase is characterised by extension accommodated by normal faulting, which resulted in breaking apart of the nappe contact and opening of tectonic window located in the canyon of Curak and Jasle streams. The last tectonic phase is characterised by reverse faulting which enabled uplift of the autochthonous Norian and Rethian Hauptdolomite in structural position above lower Jurassic carbonates. In this thesis, beside the geological map in 1:20.000 scale accompanied by geological cross-sections, the geological 3D model and interactive GIS project have been made, too. The latter provides a possibility to manipulate with collected data and also to incorporate new data from future studies

Driving processes of relative sea-level change in the Adriatic during the past two millennia: From local tectonic movements in the Dubrovnik archipelago (Jakljan and Šipan islands) to global mean sea level contributions (Central Mediterranean)

New high-resolution relative sea-level (RSL) proxy data obtained from Lithophyllum rims in the Adriatic allow usto distinguish major local, regional and global RSL driving processes during the past two millennia. RSL changeon the Elafiti islands in the Dubrovnik archipelago (Southern Adriatic) has been significantly affected by local tectonic contributions, which vary spatially and increase southeastwards from Jakljan to Grebeni. Consequently, the RSL change on northwestward islands, Jakljan and ˇSipan, is still dominantly driven by linear regional glacioisostatic adjustment (GIA) processes estimated at ~0.34 mm/yr. However, GIA effects are occasionally cancelled out by local, non-linear coseismic uplifts of small magnitude and by variations in the global mean sea level (GMSL). Thus the rapid fall in GMSL of 0.26 mm/yr offset the GIA effects between approximately ~1000–1250 cal CE, resulting in temporal hiatuses in algal rim formation. After ~1800 cal CE, GIA rates were significantly amplified by GMSL rise, which exceed 0.9 mm/yr at Jakljan and ˇSipan and goes up to 1.4 mm/yr at Koloˇcep and Grebeni, confirming the acceleration of RSL rise over the past two hundred years.The new GMSL records from the northern and southern Adriatic, allow us to reconstruct the first highresolutionGMSL curve for the Adriatic. We show that GMSL variability is in-phase with solar activity during the last two millennia, acting on cycles of ~350, 220 and 100-yrs. We also show that increased GMSL fall, which stopped the formation of algal rims around ~1000 and ~1600 cal CE, coincides with the global reduction in radiative forcing associated with the Oort and Maunder minima, with a drop in sea surface temperature (SST) and with increased salinity. Thus, our analyses revealed a consistent periodicity between the Adriatic GMSL signal, solar forcing, SST and salinity, with the most important cycle being the 350-year Great Solar Cycle

The preliminary inventory of coseismic ground failures related to December 2020 – January 2021 Petrinja earthquake series

The most recent major earthquake series struck near Petrinja (December 29th 2020 M 6.2), and triggered extensive ground failures in the wider area of Petrinja, Sisak and Glina. Coseismic ground failures including subsidence dolines, liquefaction and landslides have been documented over a large area by various experts and teams. These data are stored in the newly created inventory, which is openly presented in this paper. This inventory is administered and updated by the Croatian Geological Survey, and will be available online via a Web Map Service (WMS) (www.hgi-cgs.hr). The aim of the inventory is to not only provide data for the development of susceptibility maps and more detailed exploration for possible remediation measures, but also to define the priorities for immediate action. The earthquake triggered the rapid development of dropout dolines which endanger the local populations of the villages of Mečenčani and Borojevići. This is still an ongoing process in the vicinity of the houses and therefore in-situ exploration started immediately. Liquefaction related to alluvial sediments of the Sava, Kupa and Glina rivers occurred almost exclusively in loose and pure sands, and was accompanied by sand boils, subsidence and lateral spreading. Liquefaction also presents a greater hazard because settlement of houses and river embankments occurred. Lateral spreading caused failures of river flood embankments and natural river banks. According to the data known to date, the majority of the coseismic landslides were reactivated with minor displacements. Despite that, it has been recognised that houses at the edge, or in landslide colluvium suffered greater damage than other houses located outside the landslide impact zone