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Recurrence interval of strong earthquakes in the se Altai, Russia revealed by tree-ring analysis and radiocarbon dating

Nepop R. K., Agatova A. R.

Geochronometria

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2018

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Vol. 45, no. 1

20--33

EN

This paper presents the results of paleoseismogeological investigations including tree-ring analysis and radiocarbon dating in pleistoseist zone of the 2003 Chuya earthquake, SE Altai, Russia. Twenty-five radiocarbon dates of previously unknown evidences of prehistoric earthquakes along the fault bounders of the Chagan-Uzun massif, North Chuya and South Chuya ranges are reported. Perspectives of applying dendroseismological approach within the high mountainous seismically active southeastern part of Russian Altai are demonstrated. In addition to estimating the germination ages of trees growing on the bare surfaces of seismically triggered landslides, analysis of wood penetrating injuries in the individual tree ring series was applied for dating paleorock-falls. Analysis of distribution patterns of tree-ring anomalies and injured trees suggests a criterion of recognizing seismic origin of past rock-falls. Dendrochronologically obtained dates of abrupt intensifications of rock-falls can be considered as supposed dates of past earthquakes, which should be verified by alternative proxy data. Obtained results argue for the high regional seismicity in the second half of the Holocene. Strong earthquakes occurred here AD 1532, and 600–700, 1300–1500, 2400–2700, 3400–3700, 3800–4200 cal BP. This data clarifies the chronology of seismic events within the SE Altai. The specified recurrence interval of strong earthquakes is about 400 years during the last 4000 years.

2

Different Responses of the Radial Growth of Conifer Species to Increasing Temperature along Altitude Gradient : Pinus tabulaeformis in the Helan Mountains (Northwestern China)

Zhang L., Jiang Y., Zhao S., Dong M., Chen H. Y. H., Kang X.

Polish Journal of Ecology

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2016

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Vol. 64, nr 4

509--525

EN

Linking the response of tree growth to global warming is a key to fully appreciating the impact of climate change on forests. To examine the impacts of temperature and precipitation on tree growth, we studied the radial growth of Pinus tabulaeformis along an altitude gradient from 2032 m a.s.l. to 2361 m a.s.l. on the Helan Mountains, which is almost the northwestern limit of P. tabulaeformis distribution in China. The results showed that, radial growth of P. tabulaeformis decreased significantly (P <0.05) at the low altitude (2032 m a.s.l.) and remained almost steady at the middle and high altitude (2200 m a.s.l. and 2361 m a.s.l.) during the past decades, which was attributed to different climate-radial growth relationships at different altitudes. Total precipitation from the previous July to the current June was an important and effective climatic factor for radial growth at all altitudes. Radial growth was negatively correlated with the mean temperature of the current March at the low altitude and was positively and negatively correlated with the mean temperature of the previous October and the current July at the high altitude, respectively. Increasing temperature of the March under the context of global warming was the main reason for growth reduction at the low altitude. Radial growth at the middle and high altitudes didn't suffer from global warming. It was inferred that conifers at low altitudes of the species' dry distribution limit were more vulnerable to global warming. To cope with possible intensified drought in the growing season and growth reduction in the future, thinning and afforestation should be carried out in the forests, especially at low altitudes.

3

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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Application of Dendrochronological Analysis in Dating of Timbers from the Wieliczka Salt Mine

Szychowska-Krąpiec E.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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2003

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Vol. 51, nr 2

99-118

EN

Dendrochronological analysis was applied for dating of wood samples from timbering and wooden machines from the first level of the Wieliczka salt mine. Sampling was carried out in eight mining complexes; the Bąkle complex, the Goryszowski shaft, the Lipowiec Zamtus complex, the Taras Wodnych Gór Wschodnich complex, the Boner-Boruta complex, the area of the Powroźnik gallery, the area of the Regis shaft, and the Jan Zawachlary complex. Among over 130 samples of various tree species, timbers of Scots pine, fir and spruce were predominating. The oldest timbers, dated to the fourteenth and fifteenth centuries came from the Bąkle complex (timbering of the Dusząca chamber) and from timbering of the Goryszowski shaft. In the Dusząca chamber the oldest timbers came from fir trees growing in the second half of the fourteenth and the first half of the fifteenth century and from spruce trees felled in the second half of the fifteenth century. Fir wood from timbering of the Goryszowski shaft also came from the second half of the fifteenth century. Other samples represented somewhat younger timbers, from the last 500 years (the sixteenth to twentieth centuries). So large a spectrum of the results obtained indicates that the old mines present an excellent, though only rarely put to use, store of timbers spanning large time intervals and originating from vast areas. This opens large opportunities for constructing long absolute chronologies and for studies on identification of the origin of wood.

5

Spruce Chronology from Mt Pilsko Area. (Żywiec Beskid Range) 1641-1995 AD.

Szychowska-Krąpiec E.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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1998

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Vol. 46, nr 2

75-86

EN

Timber of spruce, a species widely spread in Europe and Asia, has been a basis of several regional dendrochronological standards. However, in Poland there is no long spruce standard of regional extent. The research underaken at Dendrochronological Laboratory, University of Mining and Metallurgy in Cracow, is the first step towards the elaboration of such a scale for the area of southern Poland. The 5BESIA chronology presented here, has been constructed for the Mt Pilsko area in Żywiec Beskid Range (S Poland) on the basis of 50 best correlated samples of contemporary, long-living spruces. Teleconnection of dendrochronological signal from Pilsko has been checked with available spruce chronologies from southern Poland, Germany, Austria, Sweden, Italy, Switzerland, France and Lithuania. The highest correlation may be observed between the 5BESIA and the German (t=5.68), Swiss (t=4.47) and Austrian (t=4.15) standards. There is no corelation with other European standards, what demonstrates unequal distribution pattern of dendrochronological signal for the spruce. The strongest signal has been noted for areas to the West and Southwest. The observed relationships can be helpful in construction and checking of the correctness of older spruce sequences and elongation of the 5BESIA chronology.