Pustertal-Mölltal-Gailtal-Drautal – Periadriatic Fault activity revealed by ruined buildings

The Periadriatic Fault system was active during the Oligocene and Miocene, producing various, large-scale strike-slip displacements. The Eastern Alpine sector is clearly visible on any relief map of the Alps, raising the interest of geologists whether it is still active today. A recent study by Prince et al. (2023, https://doi.org/10.21203/rs.3.rs-3221175/v1) measured the time of displacements by ultra-low temperature thermometers. Evidence of Late Pleistocene (>200 ky) seismotectonic activity was found. Later, historical records of seismicity along the Periadriatic Fault are exceedingly rare. Instrumental data indicate that seismotectonic deformation is mainly concentrated in the adjacent Southern Alps and Dinarides. We conducted a systematic archaeoseismological study on buildings constructed in the last two millennia along the Pustertal, Mölltal, Gailtal, Drautal, Karavanka, Savinja, and Croatian Periadriatic faults. Roman settlements (Teurnia, Magdalensberg, Celeia, Siscia) and late Medieval churches (Romanesque in Tyrol, Innichen/San Candido, Millstatt am See, and Gothic in Lienz, Villach) carry evidence for destructive earthquakes. Besides confirming the 9 AD event at Magdalensberg, the 1348 and 1690 earthquakes, and those in the late 19th and 20th centuries near Zagreb, we discovered several, previously unknown events. Those relevant to regional seismicity are listed below. Our own studies are marked bold. 1. An early 13th century earthquake severely damaged the castle of Tyrol. 2. The monastery church in Innichen/San Candido carries evidence of destruction between 1200 and 1284. 3. Churches and houses of Lienz display tilted walls supported by heavy buttresses, probably due to seismic event between 1531 and 1667. 4. Church of Sachsenburg was damaged before 1510. 5. Roman Teurnia was catastrophically destroyed in the early 3rd century, never to be rebuilt. 6. The Dominican monastery in Millstatt am See carries evidence for repeated destruction and restoration in 1201, before 1290, in 1348, and in 1690. Turbidite in the Millstätter See was formed due to the 1201 earthquake. 7. Hillside of Dobratsch suffered a catastrophic, earthquake-generated landslide in 1348. 8. Arnoldstein’s hilltop monastery was severely damaged in 1348, illustrated in a contemporary wall painting. 9. Church and town of Villach carry abundant evidence of seismic destruction in 1201, 1348, and 1690. 10. Turbidite in Wörther See was formed due to the 1348 earthquake. 11. Magdalensberg town and temple suffered damage right before 9 AD. After restoration, one more event hit the town, contributing to abandonment. 12. Homogenites in Lake Bled are witnesses to the 1348, 1511, and 1690 events. 13. Houses of downtown Ljubljana (Slovenia) carry buttresses built after the 1895 earthquake. 14. Roman settlement of Celeia (Celje, Slovenia) suffered major liquefaction event. 15. Zagreb has been repeatedly exposed to seismicity: 1880, 1906, and 2020. 16. City walls of Roman Siscia (modern Sisak, Croatia) were thrown into the moat sometime between 200 and 350 AD. 17. Petrinja earthquake in 2020, causing >100 sinkholes to open up. Altogether >400 km long faults, >15 seismic sites along 9 segments, >8 destructive earthquakes indicate that the Periadriatic fault has been seismically active during the past two millennia. Intensities up to IX were observed, and magnitudes up to M 7 were estimated, calling for further detailed studies in archaeoseismology

Tectonic Setting of the Poszukiwaczy Skarbów Cave and the Groby Cave (Kraków Gorge, Western Tatra Mts., Poland)

The study area is located in the Tatra Mts., the part of Western Carpathians. In the Poszukiwaczy Skarbów Cave and the Groby Cave a tectonics structures has been documented. The structural analysis were made. In both caves the following joints set have been identified from 4 maximum of statistic analysis: 157/85 (max.I), 143/63 (max.II), 58/63 (max.III), 304/70 (max.IV). Nevertheless joint set participation of individual caves development have been diverse. In the development of the Poszukiwaczy Skarbów Cave, the most important joint set were latitudinal which is conjugate with fractures of III. maximum. This crossing of joints sets contribute to development of the main chamber. Maximum III has been very important in the evolution of passages of the Groby Cave. Conjugated with joint of max. IV determined the conduit direction. Entrance chamber formed in this place because the overthrust disintegrated a rocks there

Extreme values of fold-related shortening in the hinterland structure of the Shilbilisaj section in the Talas Ridge (Tien Shan)

"alas Ridge forms the western part of the Tien Shan Caledonian structure. The sedimentary cover shows a thickness of about 10 km and consists of carbonate flysch and para-platform deposits metamorphosed under greenschist and lesser grade. This structure relates to the "hinterland" tectonic type, characterized by the abundance of many small and moderate-sized folds of the "similar" morphological type. Conventional cross-section balancing techniques developed for "foreland" structures, with large "parallel" folds cannot be applied correctly to such complicated structures. Thus, a special method based on the "geometry of folded domains" was developed for balancing of "hinterland" structures. To test the proposed method, we choose the westernmost Shilbilisaj profile of the Talas Ridge that consists of a large number of folds." (fragm.

Is there active tectonics at the Nile cataracts in Sudan? An archaeoseismological study

"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." (fragm.

Assessment of tectonic control on the development of low mountains moderate relief in the Outer Carpathians (Southern Poland)

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 Soła River and its 47 sub-catchments using a 25-m spatial resolution Digital Terrain Elevation Data Level 2. Additionally, we identified lineaments and knickpoints and correlated the computed results with local and regional fault networks, variations in lithology, and climate fluctuations. Obtained results indicate a significant impact of inherited tectonic structures on the relief development of the Soła River catchment, i.e., directions of principal ridges and valleys follow the orientation of main folds and faults recorded in this area. Anomalously high values of minimum bulk erosion, river gradient, and streamlength gradient index allowed us to define two areas with higher relative uplift rates: 1) the Soła Gorge and 2) the Beskid Żywiecki Mts. Polish Outer Carpathians are generally considered as an area of low strain rate and low seismic activity. However, the possibility of neotectonic processes should be considered in geohazard estimations. Observed bends in the direction of river valleys that do not correspond with changes in lithology could be related to active strikeslip faults. These are probably the reactivated basement structures, copied in the thin-skinned nappe cover, as a result of the accommodation of the Mur-Žilina Fault Zone resulting from the tectonic push of the Alcapa (Alpine-Carpathian-Pannonian) microplate against the European plate. Thus, the role of recent tectonic activity in relief development of the Soła River catchment even though appears to be subsidiary at the most, should not be excluded

Krater Ngorongoro największą atrakcją geoturystyczną ryftu Gregory’ego (północna Tanzania, Afryka) - uwarunkowania geograficzne

The caldera of an extinct Ngorongoro volcano is the largest unflooded and not destroyed type of this form on Earth. The depression itself occupies an area of nearly 300 km2, while the Crater -walls tower afew hundred metres (400--610 m) above the floor of the caldera. Almost all typicalforEast Africaplants and animals, as -well as rare, endemic and often endangered species can observed in the crater. The -unique richness and diversity of natural -world of the Xgorongoro Crater is caused exceptionally by favourable weather and hydrological conditions. These factors depend on local conditions, associated -with significant relief of this area. Probably, the most important is the richness of the Cgorongoro Crater in -water. There occur springs, perennial and seasonal rivers, marshes, swamps, as -well as reservoirs of fresh and sally -water. Essential is also the presence of the local autochthonous population of theMaasai people, -which raises the attractiveness of that localization adding so important cultural values. Due to its -unique natural and touristic -values, the Cgorongoro Conservation Area (NCA) has been established in 1959. The area was also included into the UNESCO World Cultural and Natural Heritage List. This paper presents only the geographical setting of the Ngorongoro Crater, which should be understood as its morphology, hydrological and climatic conditions, -wildlife and indigenous localpeople

Deep seismic reflection profiles in SE Poland reveal a Variscan thin-skinned fold-and-thrust belt encroaching the East European Craton

20th EGU General Assembly, EGU2018, Proceedings from the conference held 4-13 April, 2018 in Vienna, AustriaRecent years have brought a significant progress in understanding of the external Variscides in Poland. Combined POLCRUST-01 and PolandSPAN deep seismic surveys imaged for the first time a Variscan thin-skinned fold-and-thrust belt that encroaches onto a little deformed basement slope of the East European Craton (EEC) much farther eastward than the previously postulated position of the Variscan deformation front. This deformed belt consists of several tectonic units, to a various degree overprinted by Variscan shortening and inversion (Fragment tekstu)

Krater Ngorongoro największą atrakcją geoturystyczną ryftu Gregory’ego (północna Tanzania, Afryka) - dziedzictwo geologiczne

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 the located here hotspot. Due to the geotouristic attractiveness, as -well as a richness of living nature and archaeological sites -with discoveries of our ancestors, -which illustrate an important stage in the history of mankind, the area of the Ngorongoro Crater was designated a UNESCO World Cultural and Natural Heritage Site