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Elisaveta Marekova 《Acta Geophysica》2012,60(3):858-873
The earthquake recurrence time distribution in a given space-time window is being studied, using earthquake catalogues from
different seismic regions (Southern California, Canada, and Central Asia). The quality of the available catalogues, taking
into account the completeness of the magnitude, is examined. Based on the analysis of the catalogues, it was determined that
the probability densities of the earthquake recurrence times can be described by a universal gamma distribution, in which
the time is normalized with the mean rate of occurrence. The results show a deviation from the gamma distribution at the short
interevent times, suggesting the existence of clustering. This holds from worldwide to local scales and for quite different
tectonic environments. 相似文献
2.
Elisaveta Marekova 《Acta Geophysica》2016,64(4):885-903
The earthquake inter-event time distribution is studied, using catalogs for different recent aftershock sequences. For aftershock sequences following the Modified Omori’s Formula (MOF) it seems clear that the inter-event distribution is a power law. The parameters of this law are defined and they prove to be higher than the calculated value (2–1/p). Based on the analysis of the catalogs, it is determined that the probability densities of the inter-event time distribution collapse into a single master curve when the data is rescaled with instantaneous intensity, R(t; M th ), defined by MOF. The curve is approximated by a gamma distribution. The collapse of the data provides a clear view of aftershock-occurrence self-similarity. 相似文献
3.
Analysis of the spatial distribution between successive earthquakes occurred in various regions in the world 总被引:1,自引:1,他引:0
Elisaveta Marekova 《Acta Geophysica》2014,62(6):1262-1282
The earthquake spatial distribution is being studied, using earthquake catalogs from different seismic regions (California, Canada, Central Asia, Greece, and Japan). The quality of the available catalogs, taking into account the completeness of the magnitude, is examined. Based on the analysis of the catalogs, it was determined that the probability densities of the inter-event distance distribution collapse into single distribution when the data is rescaled. The collapse of the data provides a clear illustration of earthquake-occurrence self-similarity in space. 相似文献
4.
Thomas Giesecke K.D. Bennett H. John B. Birks Anne E. Bjune Elisaveta Bozilova Angelica Feurdean Walter Finsinger Cynthia Froyd Petr Pokorný Manfred Rösch Heikki Seppä Spasimir Tonkov Verushka Valsecchi Steffen Wolters 《Quaternary Science Reviews》2011,30(19-20):2805-2814
Mid to high latitude forest ecosystems have undergone several major compositional changes during the Holocene. The temporal and spatial patterns of these vegetation changes hold potential information to their causes and triggers. Here we test the hypothesis that the timing of vegetation change was synchronous on a sub-continental scale, which implies a common trigger or a step-like change in climate parameters. Pollen diagrams from selected European regions were statistically divided into assemblage zones and the temporal pattern of the zone boundaries analysed. The results show that the temporal pattern of vegetation change was significantly different from random. Times of change cluster around 8.2, 4.8, 3.7, and 1.2 ka, while times of higher than average stability were found around 2.1 and 5.1 ka. Compositional changes linked to the expansion of Corylus avellana and Alnus glutinosa centre around 10.6 and 9.5 ka, respectively. A climatic trigger initiating these changes may have occurred 0.5 to 1 ka earlier, respectively. The synchronous expansion of C. avellana and A. glutinosa exemplify that dispersal is not necessarily followed by population expansion. The partly synchronous, partly random expansion of A. glutinosa in adjacent European regions exemplifies that sudden synchronous population expansions are not species specific traits but vary regionally. 相似文献
5.
We examined the behavior of different fractal dimensions when applied to study features of earthquake spatial distribution
on different types of data. We first examined simulated spatial fields of points of different clustering level, following
the so called Soneira-Peebles model. The model was chosen because it displays some similarity to the real clustering structure
of earthquakes occurring on hierarchically ordered faults. The analysis of the capacity, clustering and correlation dimensions
revealed that their behavior did not completely correlate with the clustering level of the simulated data sets. We also studied
temporal variations of the fractal coefficients, characterizing the spatial distribution of the 1999 İzmit-Düzce aftershock
sequence. The calculated coefficient values demonstrated analogous behavior like for the simulated data. They exposed different
variability in time, but for all of them a systematic fluctuation was observed before the occurrence of the Düzce earthquake.
Our analysis revealed that although fractal coefficients could be applied to measure earthquake clustering, they should be
used with caution, trying to figure out the best coefficient for a certain data set. 相似文献
6.
Elisaveta Marekova 《Studia Geophysica et Geodaetica》2011,55(2):203-212
Series of relatively large earthquakes in different regions of the Earth were studied. The study regions are characterized
by high seismic activity recorded at contemporary seismic networks. The main purpose of this investigation is to describe
analytically the seismic process in space and time. We consider statistical distributions of the distances and the time intervals
between consecutive earthquakes. The statistical distribution of the parameters describing consecutive seismic events is approximated
with suitable characteristic functions. The main purpose of this approach is to propose formal criteria for distinguishing
among different active tectonic areas in terms of their seismic activity. 相似文献
7.
Fabrizio Murgia Riccardo Biddau Alessandro Concas Roberto Demontis Luca Fanfani Zeno Heilmann Cristian Lai Giuditta Lecca Eva Lorrai Marino Marrocu Vittorio Alessandro Marrone Laura Muscas Elisaveta Peneva Andrea Piras Massimo Pisu Gabriella Pusceddu Guido Satta Daniela Theis Andrea Vacca Paolo Valera Ana Melina Vallenilla Ferrara Ernesto Bonomi 《Earth Science Informatics》2009,2(1-2):5-21
GRIDA3 (Shared Resources Manager for Environmental Data Analysis and Applications) is a multidisciplinary project designed to deliver an integrated system to forge solutions to some environmental challenges such as the constant increase of polluted sites, the sustainability of natural resources usage and the forecast of extreme meteorological events. The GRIDA3 portal is mainly based on Web 2.0 technologies and EnginFrame framework. The portal, now at an advanced stage of development, provides end-users with intuitive Web-interfaces and tools that simplify job submission to the underneath computing resources. The framework manages the user authentication and authorization, then controls the action and job execution into the grid computing environment, collects the results and transforms them into an useful format on the client side. The GRIDA3 Portal framework will provide a problem-solving platform allowing, through appropriate access policies, the integration and the sharing of skills, resources and tools located at multiple sites across federated domains. 相似文献
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