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Seismic microzonation study for two mining cities in the SW of Kyrgyzstan

Philippe Rosset, Wyss Max

Acta Geophysica

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2023

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Vol. 71, no. 1

293--307

EN

Kyrgyzstan is an earthquake-prone country at the border of the Pamir Thrust, north of the active shortening structure of the Pamir Mountains and the intra-continental mountain belt of the Tian Shan further north. The region has had several M7+damaging earthquakes, which have killed thousands of people. In the West, the country is cut through by the 700-km long NW–SE Talas-Fergana active strike-slip fault system, where no major earthquakes have been observed in the last 250 years even though paleoseismic studies show the potential to produce M7.0+events. This study is the second part of a project to estimate the potential damage and losses on residential buildings as well as critical infrastructures in the case of a large earthquake in the two mining towns of Kadamjay and Aidarken in the SW of Kyrgyzstan. Microtremors were recorded on 82 sites and analyzed with the Horizontal-to-Vertical Spectral Ratio (HVSR) method. For each site, we estimate the average frequency of the clearest peak and its amplitude in the HVSR spectra to produce microzonation maps, in terms of response frequency. We further used these data for the calculation of ground shaking using a set of six seismic scenarios based on the known faults around the two towns. This approach has proved to be efficient in a country where the resources and available data are limited and when the time of investigation is short. The Kadamjay and Aidarken cities have been divided into different zones with specific predominant resonance frequency ranges, which information is useful for risk analysis, mitigation and buildings retrofit. In Kadamjay, three regions dominate which are related to the history of alluvial deposition in a series of terraces. The more elevated terrace could be the place of seismic site amplification. Aidarkan is much more homogenous in terms of thickness and type of alluvial deposits.

2

Tournaisian and Viséan Lophophyllum of Gorskiy (1932) from the Kirghiz Steppe and a possible ancestor of a new Bashkirian rugose coral genus from the Donets Basin (Ukraine)

Fedorowski J.

Geologos

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2017

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Vol. 23, No. 3

215--221

EN

All specimens assigned by Gorskiy (1932) to the genus Lophophyllum Milne Edwards and Haime, 1850 are revised, redescribed and reillustrated. The corallite identified by him as a second, specifically indeterminate species of Lophophyllum is here questionably included in Amygdalophyllum Dun and Benson, 1920. For the reminding specimens two new, unnamed genera are suggested. ”Lophophyllum” subtortuosum Gorskiy, 1932 belongs to a new, non-dissepimented genus of an unknown family. A possible relationship between gen. nov. 1, sp. nov. 1 and the new Bashkirian genus from the Donets Basin (Ukraine) is proposed.

3

Impact of climate change on Petrova Glacier of the Ak-Shyjrak Massif (Kyrgyzstan) using remote sensing data

Kokoeva G.

Roczniki Geomatyki

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2009

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T. 7, z. 2

55-61

EN

Global climate change occurs naturally and periodically and is often attributed to continental drift, variations in the earth's axis and orbit, variations in solar energy output and the frequency of volcanic activity. However, over the past few decades human activities have significantly altered the atmospheric composition, causing a climate change not previously experienced (IPCC, 2001). The first report of the Intergovernmental Panel on Climate Change (IPCC) assessed projections which suggested global average temperature increases between 0.15 and 0.3°C per decade from 1990 to 2005. The mountain glaciers and snow cover on average have declined in both hemispheres and the maximum areal extent of seasonally frozen ground has decreased about by 7% in the Northern Hemisphere since 1900, with decreases in spring of up to 15% (IPCC, 2007). Kyrgyzstan is one of the extensively glaciated regions in the world . A variety of available sources were used in this study in order to detect changes to the Petrova Glacier, which is one of the largest glaciers of the Ak-Shyjrak glacierized Massif in Central Tien-Shan (Kyrgyzstan). Glacier mass change is difficult to measure from the multispectral remote sensing data of Landsat, therefore glacier shrinkage was described as a loss of glacier area. The objective of this study is to characterize changes across a period of more than 60 years, from 1943 to 2006. The total area of glacier in previous years was calculated from the available cartographical data and its recent state from Landsat satellite images. A new policy of free availability of the Landsat data series allows for wider opportunities for monitoring glaciers in remote areas. The extraction of relevant parameters of glaciers from SRTM data also plays a significant role, especially in mountain areas

PL

Lodowce gór Tien-Szan są odnawialnym źródłem świeżej wody, z której korzystają miliony ludzi w Centralnej Azji. Cofanie się lodowca może być jednym z czynników globalnych zmian klimatycznych. Zgodnie z ostatnim raportem IPCC (2007) całkowity wzrost temperatury od lat 1850-1899 do lat 2001-2005 wyniósł 0.76°C. Oszacowano, że wzrost średniej temperatury o 1°C w stosunku do roku 1850 może spowodować zmniejszenie się powierzchni lodowców górskich aż o 40% i o ponad 50% zmniejszenie ich objętości. W niniejszej pracy podjęto próbę oszacowania wpływu globalnego ocieplenia na lodowiec Pietrowej, jeden z największych lodowców masywu Ak-Szijrak (Kirgistan), z wykorzystaniem analizy multispektralnych danych satelitarnych oraz dostępnych danych kartograficznych. Celem badania jest scharakteryzowanie rozmieszczenia przestrzennego Lodowca Pietrowej i jego zmian w okresie ponad 60 lat, od 1943 do 2006 roku. Zmiana lodowca bądź masy śniegowej jest trudna do zmierzenia przy użyciu multispektralnych danych satelitarnych Landsat, zatem zmniejszanie się lodowca zostało opisane jako ubytek powierzchni lodowca, który jest funkcją odległości przebytej przez cofający się brzeg lodowca. Do określenia całkowitej powierzchni lodowców zastosowano techniki przetwarzanie multispektralnych obrazów Landsat TM.

4

Rosyjska polityka w Azji Środkowej

Czarnota Zygmunt, Moszumański Zbigniew

Wiedza Obronna

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2007

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nr 2

5--16

5

Klasyfikacja gleb słonych doliny Czuj w Kirgistanie na podstawie wielospektralnych obrazów satelitarnych Landsat TM, Landsat ETM+, TERRA ASTER oraz danych naziemnych

Kokoeva G.

Teledetekcja Środowiska

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2007

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T. 37

3--50

EN

The natural conditions of Kyrgyzstan and consequences of human-induced processes, such as inappropriate methods of irrigation, have led to the extension of salt-affected soils. Extensive areas of irrigated land have been increasingly degraded by salinization from over-irrigation and other forms of inadequate agricultural practices. Between 1985 and 1990, the area of salt-affected soils increased from 666 300 ha to 1170 300 ha (Mamytov, 1995). In recent years salinity processes have been described as one of the problems of agriculture in that area. For the last ten years many none-affected soils of the Chuy Valley have become salinized. According to Mamytov et al. (1991) the total area of salt-affected soils in the Chuy Valley exceeds 259.5 thousands ha, which is more than 42% of the research area. In this research, an attempt has been made to estimate soil salinity quantitatively and also spatially by applying remote sensing techniques. Conventional methods of mapping salt-affected soils consume a lot of energy, time and money. Remote sensing enables us to detect and to map salt-affected soils by using relatively cheap multispectral satellite data such as Landsat TM, Landsat ETM+ and TERRA ASTER. The objective of this study is to identify salt-affected soils by integrating satellite images with ground-collected data. In order to achieve this goal the best algorithms of an unsupervised and a supervised classifi cation have been chosen using TNTmips software. The Normalized Difference Vegetation Index (NDVI) and the Transformed Vegetation Index (TVI) have been applied to distinguish densely and partly vegetation- covered soils, which are not salt-affected. To distinguish areas covered with stone and sands from saline soils the Salinity Index (SI) has been applied. For the differentiation of arable land which is not covered with vegetation the brightness parameter of Tasseled Cap transformation has been used. All these indices were calculated from satellite images. Finding an appropriate interpretation scheme for identifying the saltaffected soils of the Chuy Valley becomes a very important factor infl uencing the accuracy of the supervised classifi cation. The temporal change of salinity accumulation is demonstrated by comparing the classifi cation’s results of the multispectral satellite images from 1994 to those of 2001. This study also includes measurements of spectral properties of collected soil samples for better understanding the difference in classifi cation accuracy of various types of salt-affected soils. Spectral refl ectance was registered from the surfaces of saline and saline-sodic soils using fi eld luminancemeter CIMEL CE 313-21 in the following wavelength bands: 450 nm, 550 nm, 650 nm and 850 nm.