323,879 research outputs found
Comment on "Two Foreshock Sequences Post Gulia and Wiemer (2019)" by Kelian Dascher-Cousineau, Thorne Lay, and Emily E. Brodsky
No full textISSN:0895-0695ISSN:1938-2057ISSN:1938-205
Рецензія на: Bjorn Wiemer / Rainer Goldt (Hrsg.)
No full textRezensierte Publikation: Bjorn Wiemer / Rainer Goldt (Hrsg.), Die Ukraine als Objekt russischer Großmachtansprüche: Sprachen, Identitäten und Diskurse. Berlin: Frank & Timme, 2023. 364 S. ISBN 978-3-7329-8963-8
News from NERIES, SAFER, SEISTRAIN and Other Transnational European Projects
No full textNews from NERIES, SAFER, SEISTRAIN and
Other Transnational European ProjectsIstituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy
Institute of Statistical Mathematics (ISM), Tokyo, Japan
Swiss Seismological Service, Institute of Geophysics (ETH), Zürich, SwitzerlandUnpublishedErice, Italyope
Theme IV – Understanding Seismicity Catalogs and Their Problems Catalog artifacts and quality control
No full textMan-made contaminations and heterogeneity of reporting are present in all earthquake catalogs. Often they are quite strong and introduce errors in statistical analyses of the seismicity. We discuss three types of artifacts in this chapter: The presence of reported events, which are not earthquakes, but explosions; heterogeneity of resolution of small events as a function of space and time; and inadvertent changes of the magnitude scale. These problems must be identified, mapped, and excluded from the catalog before any meaningful statistical analysis can be performed. Explosions can be identified by comparing the rate of day-time to night-time events because quarries and road construction operate only during the day and often at specific hours.
Spatial heterogeneity of reporting small events comes about because many stations record small earthquakes that occur near the center of a seismograph network, but only relatively large ones can be located outside the network, for example offshore. To deal with this problem, the minimum magnitude of complete reporting, Mc, has to be mapped. Based on the map of Mc, one needs to define the area and the corresponding Mc, the choice of which leads to a homogeneous catalog. There are two approaches to the strategy for selecting an Mc and its corresponding area of validity: If one wishes to work with the maximum number of earthquake per area for statistical power of resolution, one needs to eliminate from consideration areas of inferior reporting and use a small Mc(inside), appropriate for the inside of a network. However, if one wishes to include areas outside of the network, such as offshore areas, then one has to cull the catalog by deleting all small events from the core of the network and accept only earthquakes with magnitude larger than Mc(outside). In this case, one pays with loss of statistical power for the advantage of covering a larger area.
As a function of time, changes in hardware, software, and reporting procedure bring about two types of changes in the catalog. (1) As a function of time the reporting of small earthquakes improves because seismograph stations are added or detection procedures are improved. (2) The magnitude scale is inadvertently changed due to changes in hardware, software, or analysis routine. The first problem is dealt with by calculating the mean Mc as a function of time in the area chosen for analysis. This will usually identify steps of Mc downward (better resolution with time) at fairly discrete times. Once these steps are identified, one is faced with choosing a homogeneous catalog that covers a long period, but with a relatively large Mc(long time). This way one gains coverage of time, but pays with loss of statistical power because small events, which are completely reported during recent times, have to be eliminated. On the other hand, if one wishes to work with a small Mc(recent), then one must exclude the older parts of the catalog in which Mc(old) is high.
To define the magnitude scale in a local or regional area in such a way that it corresponds to an international standard is not trivial, nor is it trivial to keep the scale constant as a function of time, when hardware, software, and reporting procedures keep changing. Resulting changes are more prominent in societies characterized by high intellectual mobility, and may not be found in totalitarian societies, where observatory procedures are adhered to with military precision.
There are two types of changes: simple magnitude shifts and stretches (or compressions) of the scale. Here, we show how to identify changes of the magnitude scale and how to correct for them, such that the catalog approaches better homogeneity, a necessity for statistical analysis
Asperity-based earthquake likelihood models for Italy
No full textThe Asperity Likelihood Model (ALM) hypothesizes that small-scale spatial variations in the b-value of the Gutenberg-Richter relationship have a central role in forecasting future seismicity. The physical basis of the ALM is the concept that the local b-value is inversely dependent on the applied shear stress. Thus low b-values (b < 0.7) characterize locked patches of faults, or asperities, from which future mainshocks are more likely to be generated, whereas high b-values (b > 1.1), which can be found, for example, in creeping sections of faults, suggest a lower probability of large events. To turn this hypothesis into a forecast model for Italy, we first determined the regional bvalue (b = 0.93 ±0.01) and compared it with the locally determined b-values at each node of the forecast grid, based on sampling radii ranging from 6 km to 20 km. We used the local b-values if their Akaike Information Criterion scores were lower than those of the regional b-values. We then explored two modifications to this model: in the ALM.IT, we declustered the input catalog for M ≥ 2 and smoothed the node-wise rates of the declustered catalog with a Gaussian filter. Completeness values for each node were determined using the probability-based magnitude of completeness method. In the second model, the hybrid ALM (HALM), as a «hybrid» between a grid-based and a zoning model, the Italian territory was divided into eight distinct regions that depended on the main tectonic regimes, and the local b-value variability was thus mapped using the regional b-values for each tectonic zone. © 2010 by the Istituto Nazionale di Geofisica e Vulcanologia
News from NERIES, SAFER, SEISTRAIN and Other Transnational European Projects
No full textNews from NERIES, SAFER, SEISTRAIN and
Other Transnational European ProjectsIstituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy
Institute of Statistical Mathematics (ISM), Tokyo, Japan
Swiss Seismological Service, Institute of Geophysics (ETH), Zürich, SwitzerlandUnpublishedErice, Italyope
Anatomía e histoquímica de órganos vegetativos de Philibertia Gilliesii, una enredadera nativa de Argentina
No full textFil: Bravi, V. S. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Morfología Vegetal; Argentina.Fil: Bravi, V. S. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Bravi, V. S. Facultad de Ciencias Químicas. Departamento de Ciencias Farmacéuticas; Argentina.Fil: Cosa, M. T. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Morfología Vegetal; Argentina.Fil: Cosa, M. T. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Pacciaroni, A. del V. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina.Fil: Pacciaroni, A. del V. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Wiemer, A. P. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Morfología Vegetal; Argentina.Fil: Wiemer, A. P. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Wiemer, A. P. Museo Botánico Córdoba; Argentina.Philibertia gilliesii Hook. & Arn. es una enredadera nativa, posee abundante látex y se encuentra ampliamente distribuida en Argentina. El objetivo del trabajo fue estudiar la anatomía e histoquímica de los órganos vegetativos con énfasis en los laticíferos. Se analizaron cortes a mano alzada de raíz, tallo y hojas; los cortes de tallo fueron sometidos a pruebas histoquímicas. La raíz es diarca y posee numerosos paquetes de esclereidas en la corteza.Fil: Bravi, V. S. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Morfología Vegetal; Argentina.Fil: Bravi, V. S. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Bravi, V. S. Facultad de Ciencias Químicas. Departamento de Ciencias Farmacéuticas; Argentina.Fil: Cosa, M. T. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Morfología Vegetal; Argentina.Fil: Cosa, M. T. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Pacciaroni, A. del V. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina.Fil: Pacciaroni, A. del V. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Wiemer, A. P. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Morfología Vegetal; Argentina.Fil: Wiemer, A. P. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Wiemer, A. P. Museo Botánico Córdoba; Argentina.Ciencias de las Plantas, Botánic
Chinese Saving Dynamics: The Impact of GDP Growth and the Dependent Share
No full textChina’s national saving rate rose rapidly in the 2000s after declining through the late 1990s. These dynamics are not explained by precautionary motives, the institutional distribution of income, or reform related processes in general. Rather, we find a compelling explanation lies with GDP growth fluctuations and movement in the dependent share in population. We estimate a vector autoregressive model for the period 1978-2008, then generate in-sample simulations that successfully replicate the 2000s runup in the saving rate. Our out of sample forecasts show the saving rate dropping in the 2010s as the dependency share falls and GDP growth moderates.
ByzRev 04.2022.022: Hans-Ulrich Wiemer (Hrsg.), Theoderich und das gotische Königreich in Italien: Berlin: Walter de Gruyter – Oldenbourg 2020.
No full text
Hans-Ulrich Wiemer (Hrsg.), Theoderich und das gotische Königreich in Italien (Schriften des Historischen Kollegs 102). Berlin: Walter de Gruyter – Oldenbourg 2020. XI, 460 S. – ISBN 978-3-11-065820-
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