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311.
In order to improve the accuracy of the spatial distribution of earthquake foci in the principal Novy Kostel focal zone, refined focal locations of about 1500 micro-earthquakes of the 1991 – 1997 period were determined using the relative Master-Event location method. To estimate the reduction in the scatter of located hypocentres, the results were compared with those obtained by routinely used FASTHYPO method and cluster analysis (the nearest-neighbour method) was applied to the located foci to evaluate the spatial distribution of the foci. Based on the results of refined location and of the cluster analysis, a concept of seismic energy release in space and time in the main focal zone was developed. Especially the January 1997 earthquake swarm was studied in detail: 946 events were located with the Master-Event location method, and the dimensions and geometry of focal clusters were determined. Type analysis was applied to waveforms to divide approximately 800 located events into eight multiplet groups to each of which a characteristic source mechanism was assigned. The spatial distribution of the foci as well as of the eight types of source mechanisms was revealed in this way and also the planes fitting the clusters of foci with two predominant source mechanisms were determined fairly well. 相似文献
312.
Janský Jaromír Horálek Josef Málek Jiří Boušková Alena 《Studia Geophysica et Geodaetica》2000,44(2):158-174
West Bohemian earthquake swarms are used to determine the parameters of simple homogeneous velocity models of the individual subregions of the given area, based on a group of earthquakes that occurred in these subregions. The grid search method is used for location. Models yielding the minimum sum of squares of the travel-time residua in locating the whole group of earthquakes in the given subregion are considered suitable. Relocation obtained by grid search is compared with that obtained by the FASTHYPO method. The computations indicate that the subregions under consideration can be, from the point of view of earthquake location, sufficiently represented by homogeneous models, but the models differ for the data from different subregions. The velocities of these models are given. The models under consideration are compared with some of the previously published 1-D models of the broader region of Western Bohemia. 相似文献
313.
Klimeš Jan Norabuena Edmundo Stemberk Josef René Miloš 《Studia Geophysica et Geodaetica》2019,63(2):257-272
Studia Geophysica et Geodaetica - A fault slip within the Ñaña tunnel Lima, Peru has been monitored since 2012. The data are recorded using an optical-mechanical 3D extensometer, capable... 相似文献
314.
Terrace pediments occupy approximately 30 per cent of the bottom of the Makhtesh Ramon erosional cirque in the central Negev Desert, Israel. River terraces and terrace pediments are genetically connected landforms, where each terrace pediment corresponds with a fluvial terrace of the same relative height. A pediment and river terrace constitute a geomorphic pair and should be regarded as chronometrically synchronous morphological elements. The formation of the terrace pediment staircases is controlled mainly by local base level changes. The present‐day configuration and overall morphology of Makhtesh Ramon formed in the early stages of its development by both stream erosion and subsequent pedimentation. Less significantly, modification by intermittent erosion alternating with periods of stability, resulted in deepening of the Makhtesh Ramon bottom. The present‐day stepped relief throughout the Makhtesh valley is, thus, a composite feature. The overall rate of terrace pediment formation in Makhtesh Ramon ranges from 0·05 to 0·10 mm a−1. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
315.
T. C. Schmidt U. Bütehorn K. Steinbach R. Kotke D. Bruns‐Nagel E. von Lw 《洁净——土壤、空气、水》2000,28(3):117-122
Aromatic amines are important metabolites of nitroaromatic explosives, hence monitoring of aromatic amines’ content at former ammunition plants is necessary. Twenty years ago, a threshold limit value of 0.1 μg/L for the sum of diazotizable aromatic amines in water distributed from the waterworks at the former ammunition plant in Stadtallendorf/Hesse was established. This value is still measured with a spectrometric sum parameter, in which diazotization and a subsequent azo coupling of the analytes are utilized. The sum parameter is well suited for the long‐term monitoring of filter installations, and it allows very quick measurements and a non‐target screening of aniline contents, both of which are important in research. Nevertheless, as several problems are associated with this parameter, we developed analytical methods suitable for the determination of the most important single compounds contributing to the overall sum. Initial results of these methods show that amphoteric anilines are of considerable importance in ammunition waste but have been neglected up to now in official monitoring schemes. The summation of single compound contents in ammunition wastewater generally gives 3 to 6 times higher values than the spectrometrically determined sum, which is mainly due to the choice of the reference substance 4‐nitroaniline in the sum parameter. 相似文献
316.
Tom Kol Petr Dobrovolný Pter Szab Tom Mikita Tom Kyncl Josef Kyncl Irena Sochov Ale Flídr David Merta Michal Rybní
ek 《第四纪科学杂志》2022,37(1):123-132
The development of settlement and building activity is the result of socioeconomic, political and demographic changes in the past. However, accurate information on temporal variation in building activity is rather limited. Dendrochronological databases containing dated historical wooden constructions provide an important resource. We used 6514 tree-felling dates to reconstruct building activity in the Czech lands for the period 1450–1950. Comparing felling dates with historical events demonstrated that building activity was negatively associated with intense wars, particularly during the Thirty Years' War (1618–1648). After the Peace of Westphalia (1648), socioeconomic renewal and demographic growth were reflected in an upsurge of building activity, especially ecclesiastical buildings. While the construction of ecclesiastical and noble buildings culminated around the 1720s, rural buildings peaked in the 1780s and the 1820s. Although no direct effect of climate was demonstrated, adverse climatic conditions leading to harvest failures and subsequent famines (e.g. the ‘Hunger Years’ 1770–1772) significantly contributed to declines in building activity. In contrast, a higher number of felling dates were detected when strong and/or frequent windstorms occurred. This study provides a comprehensive understanding of building activity in Central Europe and advocates the use of dendrochronological databases for the investigation of human activities in history. 相似文献
317.
Ladislav Bnesz Josef Hromada Janusz Kozlowski Krzysztof Sobczyk Maciej Pawlikowski 《Geoarchaeology》1995,10(4):237-255
The site of Moravany-Žakovska in western Slovakia is situated in a loessic terrain and is dated to the end of the Late Glacial Maximum. This article shows the importance of analyzing the 0.01-0.1 mm fraction to interpret the sedimentological environment and a number of measured anthropogenic indices, such as burnt quartz grains, charcoal, radiolarite chips, microflakes, and microfragments of bone. Analysis of the profile of the site through time reveals the relationship between occupational levels and phases of slope wash that occurred during wetter climatic episodes; these are separated by phases of aeolian sedimentation. At the same time, analysis of anthropogenic indices in this size fraction permitted the identification of occupational levels, including those not recorded by macrofinds. Analysis of anthropogenic indices in horizontal exposures enabled the identification of latent settlement structures such as hearths, areas of radiolarite processing, zones where mineral dyes were prepared, and other structures not recorded by macrofinds. 相似文献