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Dendrogeomorphological analysis of landslide activity along the planned S-69 road in the Węgierska Górka municipality (Beskid Śląski Mountains, S Poland)

Wiktorowski D., Krąpiec M., Lutka M.

Geology, Geophysics and Environment

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2017

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Vol. 43, no. 2

139--149

EN

Our dendrogeomorphological analysis was completed for 4 landslides, situated in the municipality of Węgierska Górka in the Beskid Śląski Mountains in Southern Poland. The local landslides pose a direct threat to the newly designed S-69 expressway running through the north-western part of the municipality. The research material consisted of 127 samples, collected with the use of a Pressler increment borer, from three species of coniferous trees (Norway spruce, Scots pine, and Silver fir). The landslide activity periods were identified on the basis of the splitting of the dendrochronological curves representing the upslope and downslope parts of the tree trunks. The largest number of the studied trees indicated reactions to substrate mass movements in 1964, 1971, 1972, 1984, 1994, 1997, 1998, and 2010. The detailed locations of the sampled trees allowed us to reconstruct the activities of particular landslide sections in time. We identified the fact that parts of the landslides located downslope of the planned road S-69 are more active than parts of the same landslides located above it on the slope. Geological conditions in the studied area favour landslide activity while precipitation is the main triggering factor of landslides.

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Dendrochronological study of the Sawicki landslide activity in the Beskid Niski Mts (Polish Flysch Carpathians)

Kiszka K.

Landform Analysis

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2016

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Vol. 32

9--26

EN

The article presents the results of the dendrogeomorphological study of the activity of the Sawicki landslide, located in the Beskid Niski Mts (Polish Flysch Carpathians). The study was conducted within two study sites in the lower part of the landslide. The landslide movements were dated using the dendrogeomorphological method, basing on the eccentricity indicators calculated for the two coniferous species, i.e. Scots pine (Pinus sylvestris) and silver fir (Abies alba). It was found landslide activity in years: 1899, 1901, 1905, 1910, 1913–1914, 1920–1921, 1929–1931, 1935, 1937, 1945, 1977, 1979, 1981, 1984–1985, 1990, 1992–1993, 1997, 2003–2004, 2006, 2010–2012. The greatest activity was characterized for the northern part of the study site B and the south-western slopes of the Szklarki stream valley (study site A). Studies have shown only a partial dependence between precipitation and landslide episodes. The data were confronted with the results of dendrogeomorphological studies, conducted in the northern and central parts of the landslide. The results demonstrate the significant complexity of mass movements within large-area landslide.

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Tree-ring based record of intra-eruptive lahar activity: Axaltzintle valley, Malinche volcano, Mexico

Franco-Ramos O., Stoffel M., Vázquez-Selem L.

Geochronometria

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2016

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Vol. 43, no. 1

74--83

EN

Lahars are a widespread phenomenon in volcanic environments and good knowledge generally exists on contemporary, syn-eruptive lahar activity. Much less data is, by contrast, available on post-eruptive lahars and/or hydrogeomorphic processes out of extinct volcanic complexes. In this study we present a reconstruction of intra-eruptive lahar activity in Axaltzintle valley (Malinche volcano) using growth-ring records of 86 Abies religiosa trees. Based on the identification of 217 growth disturbances, field evidence and hydrological records we reconstruct a total of 19 lahars for the period 1945–2011. The reconstructed lahars were mostly triggered by moderate intensity, but persistent rainfalls with sums of at least ~100 mm. By contrast, the 1998 and 2005 lahars were presumably triggered by hurricane-induced torrential rainfalls with >100 mm in three days.

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Debris-flow activity in five adjacent gullies in a limestone mountain range

Schraml K., Oismüller M., Stoffel M., Hübl J., Kaitna R.

Geochronometria

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2015

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Vol. 42, no.1

60--66

EN

Debris-flows are infrequent geomorphic phenomena that shape steep valleys and can represent a severe hazard for human settlements and infrastructure. In this study, a debris-flow event chronology has been derived at the regional scale within the Gesäuse National Park (Styria, Austria) using dendrogeomorphic techniques. Sediment sources and deposition areas were mapped by combined field investigation and aerial photography using an Unmanned Aerial Vehicle (UAV). Through the analysis of 384 trees, a total of 47 debris-flows occurring in 19 years between AD 1903 and 2008 were identified in five adjacent gullies. Our results highlight the local variability of debris-flow activity as a result of local thunderstorms and the variable availability of sediment sources.

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Floods at the northern foothills of the Tatra Mountains — A Polish-Swiss research project

Kundzewicz Z.W, Pińskwar I., Choryński A., Stoffel M, Ruiz-Villanueva V, Ballesteros-Canovas J.A, Kaczka R.J, Niedźwiedź T, Łupikasza E, Czajka B., Małarzewski Ł., Janecka K, Wyżga B, Mikuś P.

Acta Geophysica

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2014

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Vol. 62, no. 3

620--641

EN

The present paper introduces the topical area of the Polish–Swiss research project FLORIST (Flood risk on the northern foothills of the Tatra Mountains), informs on its objectives, and reports on initial results. The Tatra Mountains are the area of the highest precipitation in Poland and largely contribute to flood generation. The project is focused around four competence clusters: observation-based climatology, model-based climate change projections and impact assessment, dendrogeomorphology, and impact of large wood debris on fluvial processes. The knowledge generated in the FLORIST project is likely to have impact on understanding and interpretation of flood risk on the northern foothills of the Tatra Mountains, in the past, present, and future. It can help solving important practical problems related to flood risk reduction strategies and flood preparedness.

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Meta-analysis of dendrochronological dating of mass movements

Tumajer J., Treml V.

Geochronometria

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2013

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Vol. 40, no. 1

59-76

EN

Absolute dating of mass movements is crucial for disentangling possible release factors and determining the frequency of events. Here, we present an overview of a recent approach to den-drochronological dating of rockfalls, flows, landslides and avalanches. The results, based on 69 case-studies, show that methodological approaches to sampling and material processing differ considerably for different types of mass movements. Landslides are usually detected through abrupt growth chang-es and changes in stem eccentricity, whereas high-energy events as avalanches and flows are mostly identified by the formation of traumatic resin ducts, reaction wood, growth injuries and eccentricity changes. Cross-dating of dead wood is applicable as well. The dating of most mass movements except landslides is common, even with sub-annual resolution. In comparison to other methods of absolute dating, the main benefit of dendrochronology still lies in the high temporal resolution of the results. If living material is accessible, on-going research progress makes absolute dating of most mass-wasting events possible with sub-annual precision.

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Frequency of fast geomorphological processes in high-gradient streams: case study from the Moravskoslezské Beskydy Mts (Czech Republic) using dendrogeomorphic methods

Šilhán K.

Geochronometria

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2012

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Vol. 39, no. 2

122-132

EN

High-gradient streams are localities with the most dynamic activity of geomorphological processes in medium-high mountains. This study of the frequency of floods and debris flows in a se-lected high-gradient stream in the Moravskoslezské Beskydy Mts was based on a dendrogeomorphic approach. It makes use of the most accurate methods applied in the dating of historic geomorphologi-cal processes. Individual events were reconstructed on the basis of the dating of various growth dis-turbances displayed in 99 samples taken from 56 predominantly broad-leaved trees. As for the studied area, 26 years out of the last 113 years have been identified as years of rapid geo-morphological processes. The frequency of the processes has been high above average since the 1970s. A majority of the events can be considered as flash floods. Debris flows, which can only be observed sporadically, originate due to the reactivation of old accumulation material that subsequent-ly ends up re-accumulated on the alluvial fan at the mouth of a stream. A large number of events oc-cur in connection with extreme short-term precipitation in summer months. In addition, they are af-fected by fast snow melting in spring, which has also been proved by intra-seasonal dating of selected events.