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A strong earthquake of magnitude 6.2 with the epicentre near the town of Petrinja occurred on December 29th, 2020 in the fault zone of the right strike-slip Pokupsko Fault in Croatia. The aim of this study was to determine if there are geomorphological indicators of active tectonics in this area. General morphometric methods based on a digital elevation model with a resolution of 10 m were used. Geomorphological indicators of active tectonics were also determined based on topographic maps and hillshade relief. All the collected data were used to reconstruct the traces of the main morpholineaments on the surface and to determine the main morphostructures. It was found that the central part of the studied area, Hrastovička Gora, has morphological features possibly corresponding to a pop-up structure (positive flower) and that it consists of two separate morphostructures. They are separated from each other by an east-west oriented morpholineament, which is a possible segment of the Pokupsko Fault. Comparison of the collected results with the data on the location of the epicentres of the Petrinja series earthquakes of magnitude 4.0 and higher, which occurred in the period from December 28th, 2020 to March 3rd, 2021, indicates the possibility that these earthquakes were related to this restraining bending zone of the right horizontal Pokupsko Fault, which should be studied in more detail in the future. [ABSTRACT FROM AUTHOR]

We analyze relationships between fault and joint tectonics and landforms in the south-western part of the Broumovská vrchovina (Bohemian Massif ), where the surface topography is strongly influenced by the tectonics and lithology of the Upper Cretaceous and Permo- Carboniferous sedimentary series. We examine joint orientation using field measurements and 3D seismic tomography. The orientation of linear topographic features (morpholineaments) shows a clear dependency on two perpendicular joint systems, which exhibit either a NE -SW or a N W-SE orientation. Morpholineaments oriented in a N W-SE direction are more apparent in the surface topography and their frequency is higher. This can be attributed to the mechanical properties of NW-SE striking joints, which tend to be more open and penetrate to greater depths, making them more favourable for erosion processes. Využití geomorfologického a geofyzikálního výzkumu při studiu vztahů mezi tvary reliéfu a puklinovou tektonikou v Broumovské vrchovině (Česko) V článku byl analyzován vztah mezi zlomovou tektonikou, systémy puklin a povrchovými tvary reliéfu, a to v jz. části Broumovské vrchoviny, kde se v reliéfu výrazně projevuje tektonická a litologická predispozice sedimentárních souvrství pocházejících z období permo-karbonského a ze svrchní křídy. Systémy puklin byly zjištěny při terénních měřeních a z 3D seismické tomografie. Směry lineárních topografických prvků (morfolineamentů) vykazují závislost na systému vzájemně kolmých směrů puklin (JZ-SV a SZ-JV). Morfolineamenty směru SZ-JV se v reliéfu projevují výrazněji a frekvence jejich výskytu je také četnější. Toto může být přisouzeno jejich mechanickým vlastnostem, jelikož jsou více rozevřené a pronikají do větší hloubky. Této skutečnosti využívají jak zvětrávací, tak i erozní procesy a vede to k častějšímu zastoupení erozních forem reliéfu.

Abstract A large body of literature exists on the morphology of the Tyrrhenian Sea, the youngest back-arc basin of the Eastern Mediterranean; however, most of these studies are focused on local areas, without considering the broad regional setting. In this paper we consider the morphology of the entire Tyrrhenian Sea at a regional scale, based on a DEM analysis of middle-resolution bathymetry downloaded from the EMODnet website. Based on these data, a first morpholineaments map has been created identifying >500 features >10 km in length, without considering their tectonic settings and age. Furthermore, a Tyrrhenian regional tectonic map has been digitized from literature and the faults divided in Pre-Pliocene, Pliocene and Plio-Quaternary. Morpholineaments and tectonic lineaments have been grouped in six Tyrrhenian Sea areas plotted in rose diagrams in order to obtain the main trends in each region and to detect relationships between morphology and tectonics. Rose diagrams show that most of the identified morpholineaments have a tectonic origin, although they are not coeval, as they developed during different phases of the opening of the Tyrrhenian back-arc basin. Moreover, morpholineaments data suggest that some regions of the Tyrrhenian Sea may be dominated by a single main trend, whereas in other regions the occurrence of more trends testifies a major tectonic complexity. Highlights • A bathymetric map of the entire Tyrrhenian Sea has been created using EMODnet data. • A DEM analysis at regional scale created a morphological lineaments map. • Most of the morpholineaments have a tectonic origin, although they are not coeval. • Results provide good morphostructural patterns of large areas. [ABSTRACT FROM AUTHOR]