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This paper describes a pair of intensively studied deep seated gravitational slope deformations from the Czech Republic. Structural geological mapping and the interrogation of high resolution LiDAR DEMs have been used to reassess the extent of each slope deformation and to obtain new information about their surface morphologies. Electrical resistivity tomography has been used to image the subsurface structures while rod dilatometers and permanently installed mechanical extensometers have been used to define their kinematic behaviour. Dilatometric measurements from across a fissure the edge of the Mužský Hill DSGSD show that the progressive trend has been interspersed by five periods of movement acceleration since monitoring began in 1990 while extensometric measurements from across a second fissure about 50 m from the edge of the plateau show that this discontinuity was affected by an significant period of extension from 2004 to 2006 and a significant period of compression from 2006 to 2008. These data demonstrate that the Mužský Hill DSGSD is characterised by the lateral spreading of rigid sandstone blocks across a plastic marl formation at the edge of Příhrazy Plateau. Extensometric measurements from the Kněhyně Mountain DSGSD show that a fault located at a depth of about 25 m below the surface is characterised by progressive dilation whereas a fault located at a depth of about 57.5 m below the surface is characterised by episodic vertical dip-slip displacements. Both faults are affected by horizontal dextral strike slip displacements. These data demonstrate that the Kněhyně Mountain DSGSD is characterised by translational rocksliding associated with the neotectonic uplift of the Outer Western Carpathians. The presented kinematic data have been compared to records of precipitation, groundwater level, earthquakes, and strain changes measured by the fault displacement monitoring network EU-TecNet. Strain changes induced by the widespread redistribution of stress through the crustal appear to represent an important and hitherto underappreciated geomorphological process affecting the development of the slope deformations at Mužský Hill and Kněhyně Mountain. Future research will focus discovering whether this finding holds true for other deep seated gravitational slope deformations in different geomorphological and geological settings. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the results of a long-term monitoring study undertaken during the period 2002–2007. The study recorded the displacement of various widely-distributed tectonic structures along the generally aseismic Bohemian Massif (Czech Republic) and specifically along the Sudeten Marginal Fault Zone. The derived results were compared with data recorded over the same time period in the Upper Rhine Graben (Germany), Central Apennines (Italy), and the Gulf of Corinth (Greece). It is clear that a tectonic pressure pulse initiated a period of increased geodynamic activity across central and southern Europe during the course of our monitoring. Within the Bohemian Massif, the pressure pulse was first recorded in mid 2003 and the ensuing period of increased geodynamic activity lasted for nearly three years. This period is associated with compression along the Sudeten Marginal Fault Zone. The southern flank was repeatedly downthrust beneath the northern flank, which caused the latter to continually uplift and subside. The period of increased geodynamic activity was terminated by two strong local earthquakes. Consequently, it is considered that this period induced earthquake activity within the Bohemian Massif. When taken together, the presented data provides robust evidence for the reconfiguration of stress and strain relationships within central and southern Europe. Whilst it is possible that tectonic activity in the Alps produced a north-verging pressure pulse that affected central Europe (e.g. in the Bohemian Massif and Upper Rhine Graben), it cannot account for the pressure pulse recognised to the south (e.g. in the Central Apennines and the Gulf of Corinth). Due to the predominance of vertical movements, it is suggested that this reconfiguration results from deep seated processes within the lithosphere–asthenosphere. However, the influence of horizontal movements transmitted from the compressional zone between Africa and Europe cannot be discounted. [Copyright &y& Elsevier]

Abstract: This paper presents results of morphotectonic research carried out in order to determine the neotectonic development of the drainage network in the NE spur of the Bohemian Massif (central Europe). The area studied comprises the north-eastern sector of the Rychlebské Mts, belonging to the Sudeten Mountains and the adjacent part of the Žulovská Hilly Land in the Sudetic Foreland (Czech Republic). Analysis of drainage network characteristics such as cross-sections, erosion rate, longitudinal river profiles, stream length-gradient index (SL) and investigation of alluvial fans/terraces was performed using detailed geomorphological mapping and field examination, and DEM data. Moreover, a reconstructed neotectonic evolution was compared with present-day fault movements obtained by fault monitoring using the TM71 deformeter. The deformeter was installed directly across faults in two karst caves in the study area within the NW–SE striking Sudetic Marginal Fault (SMF) zone. This zone is one of the morphologically most prominent neotectonic structures in central Europe, separating the Sudeten Mountains from the Sudetic Foreland. Morphotectonic research reveals that segments of enhanced erosion correspond well with increased SL indices, changes in valley cross-sections and anomalies in the longitudinal profiles. The beginnings of the stretches of increased headward erosion/rejuvenated erosional phase are concentrated at the foot of marginal slopes of the mountainous sector of the study area, which supports the hypothesis that uplift of the mountainous sector is still expressed in its relief. Alluvial fans/terraces of three levels recognized in the adjacent Žulovská Hilly Land are of Middle to Late Pleistocene age: Saalian 1 (240–280 ka), Saalian 2 (130–180 ka) and Weichselian (10–80 ka), respectively. They postdate the retreat of the last continental ice-sheet, which reached the study area in Elsterian 2 (400–460 ka). Their relative heights above the river channel are greater than terrace levels of the same age along the main Nysa Kłodzka River. The height differences attain 20 m at the highest level 1, at least 8 m at level 2, and up to 2–3 m at level 3. These discrepancies imply post-Saalian 1 uplift of the Žulovská Hilly Land relative to the topographically lower Nysa Kłodzka valley. Monitoring of present-day tectonic movements in the studied area revealed slow micro-displacements (hundredths to tenths of millimetres per year). The displacements have an aseismic character and the vertical component always prevails over the horizontal one. The inferred compressive stress comes generally from the southern sector, which would imply dextral transpression in the studied portion of the SMF, where the northern part is thrusting over the southern one. The trend of these present-day movements corresponds well with uplift of the studied area north of the SMF, which is also indicated by analysis of the drainage network. It is concluded that in areas of low tectonic activity the detailed study of individual characteristics of the drainage network, particularly their spatial relationships, as well as monitoring of fault micro-displacements can reveal rates and kinematics of ongoing tectonism. [Copyright &y& Elsevier]

Abstract: This paper provides evidence for recent geodynamic activity within the Sudeten and Krušné Hory Mts. Fault Zones of the Bohemian Massif, Central Europe. Data were recorded using crack gauges and tiltmeters located on specific geological structures within caves and galleries. These data are supported by rangefinder, seismic, and groundwater observations. It is shown that a significant pressure phenomenon, here termed a pressure pulse, occurred during 2003. The pressure pulse initiated a series of tectonic deformations. In the Krušné Hory Mts., the pulse was preceded by chaotic tilt movements followed by significant tilt reorientation. Several stages of the deformation process were determined, analysed, and described. These stages represent stability, relaxation, compression, compaction, and later relaxation. The pressure pulse itself was associated with the compressional stage. Moderate, but regionally significant, earthquakes occurred during the later stages of the deformation process. This precludes the idea that they might be responsible for the initiating the recognised movements. At the same time, an unusual sequence of earthquake micro-swarms occurred in West Bohemia. These events should all be seen as the result of tectonic deformation initiated by the pressure pulse. Supplementary data indicate an affinity between the deformation process and large global disturbance within the Earth''s crust (). [Copyright &y& Elsevier]

Abstract: The NW–SE striking Sudetic Marginal Fault (SMF) is one of the most conspicuous tectonic structures in central Europe. It controls the pronounced morphotectonic escarpment of the Sudetic Mountains for a length of 130km. This paper presents the results of trenching on the SMF, undertaken in order to assess activity of the fault. The trenching technique has not hitherto been applied on either this particular fault system or elsewhere in the Bohemian Massif. However, it is the most effective tool for near-surface fault investigation in areas that are well vegetated and therefore devoid of fault outcrops. Moreover, the study area is situated in an intraplate region with a low displacement rate, which is exceeded by an erosion rate and does not favor the preservation of fault scarps. The trench sites were selected from prior DEM analyses, geomorphological fieldwork, and geophysical sounding. The trenches exposed a range of lithologies of Variscan crystalline rocks and Caenozoic sediments. At least four phases of faulting have been distinguished based on structural data, succession and age of the deformed sediments. Reverse faulting (N160°E), which displaced the Miocene sediments over the crystalline rocks, post-dates their deposition (15Ma) and pre-dates Late Glacial gelifluction. Horizontal movements that have affected the Miocene deposits along a structure striking N35°E have the same wide time constraint. Younger reverse faulting, which caused a co-seismic relief step, post-dates the Late Glacial gelifluction but preceded the early Holocene colluvium deposition (10,940±140calyrsBP). Normal faults striking N145°E, which cut the Miocene unit, might have been reactivated after the early Holocene colluvial sedimentation but before the buried soil (430±120calyrsBP). Moreover, based on the identified prehistoric earthquake, respective minimum moment magnitude M 6.3 and slip rate 0.03mm/year were estimated. [Copyright &y& Elsevier]