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

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

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

2009 ◽  
Vol 9 (3) ◽  
pp. 859-864 ◽  
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.

scholarly journals Qualitative precursory pattern before several strong earthquakes in Greece.

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.

scholarly journals Statistics of seismicity to investigate the Campi Flegrei caldera unrest

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Tramelli ◽  
C. Godano ◽  
P. Ricciolino ◽  
F. Giudicepietro ◽  
S. Caliro ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Central Area ◽  
Seismic Energy ◽  
Progressive Increase ◽  
Campi Flegrei ◽  
Cumulative Number ◽  
Seismic Parameters ◽  
Seismicity Rate ◽  
Seismic Catalogue ◽  
Vertical Ground

AbstractThe knowledge of the dynamic of the Campi Flegrei calderic system is a primary goal to mitigate the volcanic risk in one of the most densely populated volcanic areas in the world. From 1950 to 1990 Campi Flegrei suffered three bradyseismic crises with a total uplift of 4.3 m. After 20 years of subsidence, the uplift started again in 2005 accompained by a low increment of the seismicity rate. In 2012 an increment in the seismic energy release and a variation in the gas composition of the fumaroles of Solfatara (in the central area of the caldera) were recorded. Since then, a slow and progressive increase in phenomena continued until today. We analyze the INGV - Osservatorio Vesuviano seismic catalogue of Campi Flegrei from 2000 to 2020 in order to look for any variation in the seismic parameters and compare them with geochemical monitored ones. A remarkable correlation between independent variables of earthquake cumulative number, CO/CO2 values and vertical ground deformation reveals a likely common origin. Moreover the correlation between all the variables here analysed enlightens that the same origin can cause the temporal behavior of all these variables. We interpret the seismological, geochemical and geodetic observable in terms of the injection of magmatic fluids into the hydrothermal system or its pressurization.

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

2004 ◽  
Vol 36 (3) ◽  
pp. 1362
Author(s):  
I. Baskoutas ◽  
G. Panopoulou ◽  
G. Papadopoulos
Keyword(s):  
Temporal Variation ◽  
Seismic Activity ◽  
Time Window ◽  
Energy Parameter ◽  
Aegean Sea ◽  
B Value ◽  
Seismogenic Zone ◽  
Earthquake Catalog ◽  
Estimation Model ◽  
Seismic Parameters

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

scholarly journals Statistics of Seismicity to Investigate the Campi Flegrei Caldera Unrest

2021 ◽  
Author(s):  
Anna Tramelli ◽  
Cataldo Godano ◽  
Patrizia Ricciolino ◽  
Flora Giudicepietro ◽  
Stefano Caliro ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Central Area ◽  
Seismic Energy ◽  
Progressive Increase ◽  
Campi Flegrei ◽  
Cumulative Number ◽  
Seismic Parameters ◽  
Seismicity Rate ◽  
Seismic Catalogue ◽  
Vertical Ground

Abstract The knowledge of the dynamic of the Campi Flegrei calderic system is a primary goal to mitigate the volcanic risk in one of the most densely populated volcanic areas in the world. From 50s to 80s Campi Flegrei suffered three bradyseismic crises with a total uplift of almost 4.3 m. After a period of subsidence of 20 years, the uplift started again in 2005 accompanied by a low increment in the seismicity rate. In 2012 an increment in the seismic energy release and a variation in the gas composition of the fumaroles of Solfatara (in the central area of the 1 caldera) were recorded. Since then, a slow and progressive increase in phenomena continued until today. We analyze the seismic catalogue of Campi Flegrei from 2000 to 2020 collected by INGV-Osservato-rio Vesuviano to look for any variation in the seismic parameters and compare them with geochemical monitored ones. A remarkable correlation between independent variables as earthquake cumulative number, CO/CO 2 values and vertical ground deformation reveals a likely common origin. The interpretation of the seismological, geochemical and geodetical observable brings back to the injection of magmatic fluids into the hydrothermal system or its pressurization.

Earthquake density along the Western Alpine Arc

2020 ◽  
Author(s):  
Christian Sue ◽  
Margot Mathey ◽  
Estelle Hannouz ◽  
Andrea Walpersdorf ◽  
Stephane Baize
Keyword(s):  
Template Matching ◽  
Active Fault ◽  
Seismic Energy ◽  
B Value ◽  
Space Distribution ◽  
Seismic Catalogue ◽  
Density Maps ◽  
Seismic Swarms ◽  
Regional Tectonic ◽  
Seismic Networks

<p>We propose a new analysis of the W-Alpine seismicity based on space and time distributions along the Alpine arc. The overall area bears witness of a relatively important seismic activity localized along the so-call Briançonnais and Piemontais seismic arcs, but also along alignments corresponding to individualized active fault, e.g. in front of the Belledonne massif, and locally in form of important seismic swarms (Ubaye, Maurienne, Mont-Blanc). The regional tectonic regime is well analyzed (see for instance Mathey et al., this session), with detailed mapping of both the stress and strain fields. However, actual available studies do not take into account the time and space distributions. Our study is developed using several available datasets covering various time spans and various strategies (local and regional seismic networks, template matching, historical seismic catalogue). We focus firstly on the space distribution of the activity along the arc, taking into account: (i) the simple occurrence of seismic events to calculate regional density maps, also investigating the B-value mapping; and (ii) the energy density, using the seismic moment fluxes per surface unit as a proxy. On this basis, we secondly analyze the time evolution of the seismicity, which is actually limited by the available dataset’s time span. Our integrated analyze focusses on 3 primary targets: (i) to compare the information arising from the different databases; (ii) to compare the most active zones in terms of earthquake occurrence vs. seismic energy released; (iii) to unravel potential evolutions or establish relative steadiness in alpine seismicity through time. This work will finally allow to better understand and discuss the Alpine seismicity’s mechanisms, in relation with the actual dynamics of this orogen.</p>

scholarly journals Temporal variation of seismic parameters in the western part of the India-Eurasia plate collision zone

2011 ◽  
Vol 1 (1) ◽  
pp. 3 ◽  
Author(s):  
Ioannis Baskoutas ◽  
George Popandopoulos ◽  
Prasanta Chingtham
Keyword(s):  
Seismic Hazard ◽  
Temporal Variation ◽  
Strong Earthquake ◽  
Earthquake Forecasting ◽  
Target Area ◽  
Origin Time ◽  
Seismic Parameters ◽  
Strong Earthquakes ◽  
Mean Values ◽  
North West

We examined the temporal seismicity variation in the north-west Himalayas and the adjacent regions in relation to strong earthquake occurrences in the period 1970-2010. The aim was to promote seismic hazard assessment and to show the possibilities of strong earthquake forecasting by means of the FastBEE computer tool. The temporal variation of the seismicity is expressed in terms of three basic seismic parameters: the logarithm of the number of earthquakes logN, the seismic energy released in the mode logE2/3 and the b-value of the earthquake magnitude-frequency distribution expressed by the Gutenberg-Richter relation. Significant changes to relative mean values, forming consecutive relative minima and maxima, of the obtained temporal variation series of the seismicity parameters can be considered anomalies. These anomalies were investigated before strong (magnitude Mw≥5.6.) earthquake occurrences and were successfully correlated with 12 strong earthquakes. The mean time of the duration of the anomalies before the origin time of the impending earthquake were estimated to be equal to 3.3±1.3 years. We conclude that, in the region under study, the established correlations can be useful for the intermediate-term forecasting of strong earthquakes and that the continuous monitoring of the temporal evolution of seismicity by means of the FastBEE tool can contribute to the evaluation of the seismic hazard status in a target area. The available earthquake data and the results obtained indicate that after the beginning of 2006, the temporal variation of the seismicity does not present clear prognostic anomalies. This behavior is compatible with the absence of earthquakes with a magnitude of Mw 6.0 or more in the area examined.

scholarly journals Study of the seismicity temporal variation for the current seismic hazard evaluation in Val d'Agri, Italy

2014 ◽  
Vol 14 (12) ◽  
pp. 3169-3174 ◽  
Author(s):  
I. Baskoutas ◽  
A. D'Alessandro
Keyword(s):  
Time Series ◽  
Seismic Hazard ◽  
Temporal Variation ◽  
High Probability ◽  
Seismic Energy ◽  
B Value ◽  
Hazard Evaluation ◽  
Magnitude Distribution ◽  
Seismicity Pattern ◽  
Seismic Hazard Evaluation

Abstract. This study examines the temporal variation of the seismicity in the Val d'Agri (southern Italy) and adjacent areas, for the current seismic hazard evaluation. The temporal variation of the seismicity is expressed as time series of the number of earthquakes, b value of Gutenberg–Richter relationship or b value of the frequency–magnitude distribution and the seismic energy released in the form of logE2/3. The analysis was performed by means of a new research tool that includes visualizing techniques, which helps the interactive exploration and the interpretation of temporal variation changes. The obtained time series show a precursory seismicity pattern, characterized by low and high probability periods, which preceded earthquakes of magnitude M ≥ 4.0. The 75% of the examined cases were successfully correlated with a change in seismicity pattern. The average duration of the low and the high probability periods is 10.6 and 13.8 months respectively. These results indicate that the seismicity temporal variation monitoring in a given area and the recognition of the low and high probability periods can contribute to the evaluation, in regular monthly intervals, of current seismic hazard status.

scholarly journals Precursory seismicity pattern before strong earthquakes in Greece

2014 ◽  
Vol 3 (1) ◽  
Author(s):  
Ioannis Baskoutas ◽  
George Anatoli Papadopoulos
Keyword(s):  
Temporal Variation ◽  
Seismic Hazard Assessment ◽  
Seismic Parameters ◽  
Strong Earthquakes ◽  
Seismicity Pattern ◽  
Time Period ◽  
Quantitative Characteristics ◽  
Precursory Seismicity ◽  
Remarkable Relation ◽  
Qualitative And Quantitative Characteristics

The temporal variation of seismicity, based on the retrospective analyses of three seismic parameters <em>i.e.</em>, number of earthquakes, bvalue and energy released, have shown significant changes. Their remarkable relation with strong earthquakes occurrence was formulated as a qualitative character precursory seismicity pattern, which were interpreted in terms of a strong earthquakes occurrence preparation phases. The main characteristic of this pattern is that permits the identification of two period of low and high probability for an earthquake occurrence, suggesting its utility in the current seismic hazard assessment, by the continuous monitoring of the temporal variation of the seismic parameters in a given area. This paper investigates the qualitative and quantitative characteristics of the proposed precursory seismicity pattern, before al strong earthquakes occurrence in Greece the time period 2000-2008.

Strong earthquake activity influenced by solar flare intensity

2021 ◽  
Author(s):  
Gerald Duma
Keyword(s):  
Solar Flares ◽  
Strong Earthquake ◽  
Temporal Variations ◽  
Seasonal Effect ◽  
Earthquake Activity ◽  
Strong Earthquakes ◽  
International Service ◽  
Earthquake Frequency ◽  
Magnetic Index ◽  
Magnetic Disturbances

&lt;p&gt;Based on the comprehensive earthquake catalogue USGS ( HYPERLINK&lt;span&gt;&amp;#160; &lt;/span&gt;https://earthquake.usgs.gov) the paper demonstrates that strong earthquake activity, seismic events with M&amp;#8805;6, exhibits a seasonal trend. This feature is the result of&lt;span&gt;&amp;#160; &lt;/span&gt;analyses of earthquake data for the N- and S- Earth Hemisphere in period 2010-2019. It can be shown also for single earthquake prone regions as well, like Japan, Eurasia, S-America.&lt;/p&gt;&lt;p&gt;Any seasonal effect suggests an external influence. In that regard, one can think also of a solar-terrestrial effect, that is suggested already in several studies (e.g&lt;span&gt;&amp;#160; &lt;/span&gt;M.Tavares, A.Azevedo, 2011; D.A.E. Vares, M.A.Persinger,2014; G.Duma, 2019). This assumption leads to the question: Which dynamic process can cause a trigger effect for strong earthquakes in the Earth's lithosphere.&lt;/p&gt;&lt;p&gt;In this study the intensity of solar flares and the resulting radiation, the solar wind, towards the Earth was taken into account. An appropriate parameter which has been regularity measured and reported for many decades and which reflects the intensity of solar radiation is the magnetic index Kp. It is measured at numerous geomagnetic observatories and describes the magnetic disturbances in nT within 3 hour intervals, respectively. Averages of all the measured 3-hour values are then published as Kp, therefore considered a planetary parameter (International Service of Geomagnetic Indices ISGI,France).&lt;/p&gt;&lt;p&gt;The temporal variations of strong earthquake activity over 10 years and their energy release was compared with the above mentioned index Kp. Actually, a distinct correlation between the two quantities, Kp and earthquake frequency, resulted in cases of different regions as well as globally.&amp;#160;Another essential result of the study is that maxima of Kp preceed those of earthquake activity by about 60 to 80 days in most cases. The mechanism has not yet been modeled satisfactorily.&lt;/p&gt;

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