LONG TEMPORAL VARIATION OF SEISMIC PARAMETERS FOR SEISMIC PATTERNS IDENTIFICATION IN GREECE

A new approach of detailed spatio-temporal variation analysis of seismic data is proposed by means of FastBEE (Fast estimation of Big Expected Earthquake) aiming at the regional monitoring of seismic activity for premonitory seismic patterns identification. For the investigation of temporal variation, a set of seismic parameters is used, like the logarithm of the number of earthquakes logN, estimates of 6-value obtained by the maximum likelihood estimation model, time clustering of seismic activity AR(t) and of energy released EM, since they can be considered as precursory seismological indicators. Earthquake catalog data, used in this approach, were elaborated in order to construct the time series for each parameter within a time window, large enough, as to guarantee statistical meaningful result. The Hellenic trench-arc region under investigation is chosen in the basis of its seismotectonic characteristics, in relation to the spatial extent of the seismogenic zone. The tools were tested, for long temporal variation features in the Ionian Islands Sea and the North Aegean Sea regions and its successful applicability is presented. The rise of irregularity, along these temporal profiles, was formulated in specific quantitative premonitory seismic pattern. In most of the cases, FastBEE premonitory pattern found shows significant changes from the background values of each parameter. Parameter logN shows a valley form curve, which start to increase before the expected earthquake occurrence, as well as the energy parameter E273, while b-value temporal estimates are forming a mountain shape curve, before the occurrence of a big earthquake. Instead, parameter ÙR(t) present a rapid fluctuation, without any kind of premonitory character

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Effects of temporal variations in seismicity on seismic hazard

Bulletin of the Seismological Society of America ◽

10.1785/bssa0710010321 ◽

1981 ◽

Vol 71 (1) ◽

pp. 321-334

Author(s):

Robin K. McGuire ◽

Theodore P. Barnhard

Keyword(s):

United States ◽

Seismic Hazard ◽

Seismic Activity ◽

Time Window ◽

Hazard Analysis ◽

The United States ◽

Temporal Variations ◽

Seismogenic Zone ◽

Eastern United States ◽

Ground Shaking

abstract The accuracy of stationary mathematical models of seismicity for calculating probabilities of damaging shaking is examined using the history of earthquakes in China from 1350 A.D. to 1949 A.D. During this time, rates of seismic activity varied periodically by a factor of 10. Probabilities of damaging shaking are calculated in 62 cities in North China using 50 yr of earthquake data to estimate seismicity parameters; the probabilities are compared to statistics of damaging shaking in the same cities for 50 yr following the data window. These comparisons indicate that the seismic hazard analysis is accurate if: (1) the maximum possible earthquake size in each seismogenic zone is determined from the entire seismic history rather than from a short-time window; and (2) the future seismic activity can be estimated accurately. The first condition emphasizes the importance of realistically estimating the maximum possible size of earthquakes on faults. The second indicates the need to understand possible trends in seismic activity where these exist, or to develop an earthquake prediction capability with which to estimate future activity. Without the capability of estimating future seismicity, stationary models provide less accurate but generally conservative indications of seismic ground-shaking hazard. In the United States, the available earthquake history is brief but gives no indication of changing rates of activity. The rate of seismic strain release in the Central and Eastern United States has been constant over the last 180 yr, and the geological record of earthquakes on the southern San Andreas Fault indicates no temporal trend for large shocks over the last 15 centuries. Both observations imply that seismic activity is either stationary or of such a long period that it may be treated as stationary for seismic hazard analyses in the United States.

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GIS-Based Mapping of Seismic Parameters for the Pyrenees

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi9070452 ◽

2020 ◽

Vol 9 (7) ◽

pp. 452 ◽

Cited By ~ 1

Author(s):

José Lázaro Amaro-Mellado ◽

Dieu Tien Bui

Keyword(s):

Information System ◽

Geographic Information System ◽

B Value ◽

Earthquake Catalog ◽

Maximum Magnitude ◽

Seismic Parameters ◽

National Geographic ◽

Continuous Map ◽

Starting Point ◽

Central Pyrenees

In the present paper, three of the main seismic parameters, maximum magnitude -Mmax, b-value, and annual rate -AR, have been studied for the Pyrenees range in southwest Europe by a Geographic Information System (GIS). The main aim of this work is to calculate, represent continuously, and analyze some of the most crucial seismic indicators for this belt. To this end, an updated and homogenized Poissonian earthquake catalog has been generated, where the National Geographic Institute of Spain earthquake catalog has been considered as a starting point. Herein, the details about the catalog compilation, the magnitude homogenization, the declustering of the catalog, and the analysis of the completeness, are exposed. When the catalog has been produced, a GIS tool has been used to drive the parameters’ calculations and representations properly. Different grids (0.5 × 0.5° and 1 × 1°) have been created to depict a continuous map of these parameters. The b-value and AR have been obtained that take into account different pairs of magnitude–year of completeness. Mmax has been discretely obtained (by cells). The analysis of the results shows that the Central Pyrenees (mainly from Arudy to Bagnères de Bigorre) present the most pronounced seismicity in the range.

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New tool for the spatio-temporal variation analysis of seismic parameters

Natural Hazards and Earth System Science ◽

10.5194/nhess-9-859-2009 ◽

2009 ◽

Vol 9 (3) ◽

pp. 859-864 ◽

Cited By ~ 13

Author(s):

G. A. Papadopoulos ◽

I. Baskoutas

Keyword(s):

Temporal Variation ◽

Seismic Energy ◽

B Value ◽

Research Tool ◽

Earthquake Activity ◽

Seismic Parameters ◽

Mean Values ◽

Seismicity Parameters ◽

Spatio Temporal ◽

New Research

Abstract. In this paper a new research tool called FastBEE (Fast Estimation of Expected Big Earthquake) is proposed, for the analysis of three basic seismic parameters, (the number of earthquakes N, b-value, and the seismic energy released in the form logE2/3), in order to examine their spatio-temporal variation behavior. The developed research tool is suited to analyze earthquake catalogs and it comprise new interactive visualization techniques for the exploration of the results. The tool was tested in several seismic active areas of the Hellenic territory and a case study of its applicability is presented. It is observed that the results of the seismicity parameters analysis show a clear temporal fluctuation, with respect to their mean values. Such a behavior can be interpreted as the result of the geodynamic process acting in the region. In several cases the observed significant changes can be related to strong earthquakes, so that they can be considered as precursor indicating the preparation stage for an impending strong earthquake activity.

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Qualitative precursory pattern before several strong earthquakes in Greece.

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.10949 ◽

2016 ◽

Vol 47 (3) ◽

pp. 1061

Author(s):

I. Baskoutas ◽

G. Papadopoulos

Keyword(s):

Temporal Variation ◽

Continuous Monitoring ◽

B Value ◽

Earthquake Catalogue ◽

Earthquake Parameters ◽

Seismic Parameters ◽

Strong Earthquakes ◽

Mean Values ◽

Seismicity Pattern ◽

Time Period

The temporal variation of the seismicity, based on the analysis of three seismic parameters i.e., number of earthquakes, b-value and energy released, were investigated before several strong earthquakes occurrence in Greece the time period 2000-2008. The seismic parameters estimates were obtained by the means of new tool, suited to analyze earthquake catalogue, and visualize their spatio-temporalvariation behaviour. The seismic data used were taken from the earthquake catalogue of the Geodynamic Institute of National Observatory of Athens, Greece. The obtained temporal variation series shows significant changes around their relative mean values, which specific phases can be related to the strong earthquakes preparation stages. This relation shows remarkable temporal regularity so that itcan be establish considered as a precursor seismicity pattern. These results suggest that identification of this behaviour, by the continuous monitoring of the temporal variation of the seismic parameters, can contribute to the assessment of the current seismic hazard and to the impending strong earthquake parameters evaluation, in a given area.

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SPACE REGULARITY MANIFESTATION OF THE TEMPORAL VARIATION OF SEISMIC PARAMETERS: POSSIBILITY FOR THE STRONG SEISMIC ACTIVITY ASSESSMENT

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.11403 ◽

2017 ◽

Vol 43 (4) ◽

pp. 2125

Author(s):

George Popandopoulos ◽

I. Baskoutas

Keyword(s):

Temporal Variation ◽

Seismic Energy ◽

B Value ◽

Data Sets ◽

Earthquake Activity ◽

Seismic Parameters ◽

Strong Earthquakes ◽

Seismic Catalogue ◽

Local Areas ◽

Earthquake Predictions

In the present work the detailed analysis of the space-time variation, of the seismic energy released and b-value was performed, in order to study the space regularity manifestation of the temporal variation of seismic parameters, to test the reliability of the results and to compare the obtained temporal profiles in relation to the strong earthquake activity. The study was carried out in the subduction zone along the western part of the Hellenic trench arc system. The earthquakes data, witch occurs in the five adjacent local areas in the period 1980 -2007 were used. The reliability of the results is tested positively for “internal” dubiety, against independent seismic data sets from adjacent local areas, being in common the processing method, and the properties of seismic catalogue. It was found that in the majority of the cases (23 of 32) the significant temporal variation changes, considered as anomalies, can be related to the preparation process of the strong earthquakes Ms>5.7, acting as intermediate term precursors. Based on these findings the quality index of the successful intermediate term earthquake predictions reach up to 71.9%. It is observed that the temporal variation of the seismic energy released anomalies were time shifted in respect to the central areas, toward to N-NE and S-SE direction. Moreover it is found that the strong earthquakes occurrence also shows immigration, in respect to the central areas, along the concatenation of the adjacent local areas. These two observations may reveal the formation of a tectonic wave, in the broader area south of Zakynthos Island, Its velocity was estimated to be as 100 to 150 km/year

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Morphotectonic Analysis along the Northern Margin of Samos Island, Related to the Seismic Activity of October 2020, Aegean Sea, Greece

Geosciences ◽

10.3390/geosciences11020102 ◽

2021 ◽

Vol 11 (2) ◽

pp. 102

Author(s):

Paraskevi Nomikou ◽

Dimitris Evangelidis ◽

Dimitrios Papanikolaou ◽

Danai Lampridou ◽

Dimitris Litsas ◽

...

Keyword(s):

Fault Zone ◽

Seismic Activity ◽

Volcanic Rocks ◽

Active Tectonics ◽

Normal Fault ◽

Aegean Sea ◽

Northern Margin ◽

The North ◽

Eastern Aegean ◽

Half Graben

On 30 October 2020, a strong earthquake of magnitude 7.0 occurred north of Samos Island at the Eastern Aegean Sea, whose earthquake mechanism corresponds to an E-W normal fault dipping to the north. During the aftershock period in December 2020, a hydrographic survey off the northern coastal margin of Samos Island was conducted onboard R/V NAFTILOS. The result was a detailed bathymetric map with 15 m grid interval and 50 m isobaths and a morphological slope map. The morphotectonic analysis showed the E-W fault zone running along the coastal zone with 30–50° of slope, forming a half-graben structure. Numerous landslides and canyons trending N-S, transversal to the main direction of the Samos coastline, are observed between 600 and 100 m water depth. The ENE-WSW oriented western Samos coastline forms the SE margin of the neighboring deeper Ikaria Basin. A hummocky relief was detected at the eastern margin of Samos Basin probably representing volcanic rocks. The active tectonics characterized by N-S extension is very different from the Neogene tectonics of Samos Island characterized by NE-SW compression. The mainshock and most of the aftershocks of the October 2020 seismic activity occur on the prolongation of the north dipping E-W fault zone at about 12 km depth.

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Investigation of Feller-Buncher Performance Using Weibull Distribution

Forests ◽

10.3390/f12030284 ◽

2021 ◽

Vol 12 (3) ◽

pp. 284

Author(s):

Ebru Bilici

Keyword(s):

Weibull Distribution ◽

Shape Parameter ◽

B Value ◽

Productivity Analysis ◽

Volume Data ◽

Estimation Model ◽

Distribution Method ◽

Timber Volume ◽

C Value ◽

The Right

With the advancement of technology in forestry, the utilization of advanced machines in forest operations has been increasing in the last decades. Due to their high operating costs, it is crucial to select the right machinery, which is mostly done by using productivity analysis. In this study, a productivity estimation model was developed in order to determine the timber volume cut per unit time for a feller-buncher. The Weibull distribution method was used to develop the productivity model. In the study, the model of the theoretical (estimated) volume distributions obtained with the Weibull probability density function was generated. It was found that the c value was 1.96 and the b value was 0.58 (i.e., b is the scale parameter, and c is the shape parameter). The model indicated that the frequency of the volume data had moved away from 0 as the shape parameter of the Weibull distribution increased. Thus, it was revealed that the shape parameter gives preliminary information about the distribution of the volume frequency. The consistency of the measured timber volume with the estimated timber volume strongly indicated that this approach can be effectively used by decision makers as a key tool to predict the productivity of a feller-buncher used in harvesting operations.

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