Yazarlar

  • MakaleAçık Erişim2017Scopus SJRQ2
    Spatial and temporal analysis of recent seismicity in different parts of the vlora-lushnja-elbasani-dibra transversal fault zone, Albania

    Ormeni, Rrapo; öZtürk, Serkan; Fundo, Akli; çElik, Kemal

    Spatial and temporal evaluation of current seismic activity throughout the Vlora- Lushnja-Elbasani-Dibra (VLED) transversal fault zone were carried out at the beginning of year 2016. The seismotectonic b-value, fractal dimension Dc-value and precursory seismic quiescence Z-value are considered for a detailed statistical analysis. Completeness magnitude Mc-value varies from 2.5 to 2.7 for different parts of the VLED fault zone. The b-value is calculated as 1.10±0.04 for the south western part and 1.13±0.05 for the middle part, whereas it is estimated as 0.94±0.07 for the north eastern part of the study region. These results reveal that b-values for all regions are well represented by a b-value typically close to 1.0. There are clear decreasing trends in temporal changes of b-values before the occurrences of some strong main shocks. On the contrary, no earthquakes are observed in some periods after decrease of b-value. Dc-values are computed as 2.66±0.04 for the south western part, 2.64±0.03 for the middle part and 2.15±0.02 for the north eastern part of the VLED fault zone. These rather large values show that earthquake activity is more clustered at larger scales or in smaller areas in the study area. Considering the phenomenon of seismic quiescence as a precursor of the main earthquakes gives successful outcomes in defining the potential anomalies and possible locations of future earthquakes. Quiescence analysis of current seismicity at the beginning of 2016 in the VLED fault zone is performed with the test of standard normal deviate Z-value. Distributions of resulting Z-values show six anomalous regions along the different parts of the VLED fault zone. These quiescence areas are detected at (i) 40.81°N- 19.86°E (including Kuc-Bubullim, southeast of Lushnja town), (ii) 41.00°N-20.01°E (in the Cerriku, south of Elbasani town), (iii) 41.31°N-20.13°E (around Bene-Qafe, northeast of Elbasani town), (iv) 41.43°N-20.21°E (Krasta-Batra, south of Bulqiza town), (v) 41.28°N-20.49°E (including Carrishta-Stebleve, northeast of Librazhdi town), (vi) 41.51°N-20.51°E (including Qerrenec-Gjorica, west of Dibra town). As an important result, analyses of spatial and temporal characteristics of the earthquake activity may supply significant clues for revealing the future seismic hazard along the VLED fault zone, and these anomaly regions may be interpreted as the locations of next possible earthquakes.

    AtıfScopus11WoS6OpenAlex11
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  • MakaleAçık Erişim2017Scopus SJRQ3
    Space-time assessing of the earthquake potential in recent years in the Eastern Anatolia region of Turkey; [Evaluación espacio-temporal del potencial de terremotos en los años recientes para la región de Anatolia, en el este de Turquía]

    Öztürk, S.

    In this study, a statistical analysis is carried out to reveal the current earthquake potential in the Eastern Anatolia region of Turkey. For this purpose, a space-time assessing based on the recent changes in Gutenberg-Richter b-value, seismic quiescence Z-value, cumulative moment, annual probability and recurrence time of earthquakes is achieved. Temporal variation of b-value indicates that average b-value decreased from 1.25±0.02 between 2002 and 2010 to 1.08±0.02 between 2011 and 2015. A clear quiescence in the seismic moment in recent years may be a clue foretelling the occurrence of an intense event. Annual probability of the earthquakes between 3.5 and 4.0 magnitude levels exhibits a value equal to and larger than 30. Recurrence time of the earthquakes has a value between 2.0 and 3.0 years for magnitude level of 6.0, and a value between 6.0 and 7.0 years for magnitude level of 7.0. A significant decrease in b-value and clear quiescence anomalies in Z-value at the beginning of 2015 are observed in the several same regions. These areas cover the Central Anatolia Fault Zone, Malatya and Ovacık faults, the southeastern part of the Eastern Anatolia Fault Zone, and the junction of the Eastern Anatolia and Dead Sea Fault Zones. In these anomaly regions, a decreasing trend in b-value may be an indicator of stress increases and an increasing trend in Z-value may show the quiescence areas before the next earthquake occurrences. As a remarkable fact, these areas in the Eastern Anatolia region may be interpreted as one of the most likely locations for the major earthquakes in the future.

    AtıfScopus25WoS20OpenAlex24
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  • MakaleYayıncıda açık erişim2015Scopus SJRQ2
    A study on the correlations between seismotectonic b-value and Dc-value, and seismic quiescence Z-value in the western anatolian region of Turkey

    Öztürk, Serkan

    The Western Anatolian region is one of the most seismically active sectors of Turkey where small-magnitude events with considerable clustering occur frequently. The spatial and temporal behaviors of seismic activity as quantified by the fractal dimension Dc-value, seismotectonic b-value and seismic quiescence Z-value are investigated for the Western Anatolian region. For this purpose, a statistical relationship is developed between b and Dc-values, and regional and temporal changes of these parameters are analyzed in order to reveal the potential of future earthquakes in the study region. By using standard deviate Z-value, current seismicity rate changes are estimated in the beginning of 2014. The Western Anatolian region is divided into 18 different seismogenic subregions. Orthogonal regression fit is preferred in order to estimate more up-to-date and reliable statistical correlation between two seismotectonic parameters. The relationship of Dc=2.74-0.29*b is computed with a significant negative correlation (r = -0.73) between b and Dc-values for the Western Anatolian earthquake distributions. There are clear fluctuations in the temporal changes of these two parameters and the same results are relatively obtained in previous studies in literature. Lower b-values smaller than 1.0 and also higher Dc-value are observed in the Burdur fault zone and Kütahya graben. In addition, the regions in which the lower b-values and the higher Z-values are estimated cover the Burdur fault zone, Aliağa-Dumlupınar faults and Bakırçay grabens. Consequently, the relationships between seismic bvalue, fractal dimension Dc-value and seismic quiescence Z-value may provide important evidences to put forth the next earthquake potential in Western Anatolia. In addition, monitoring of microseismic activity and behaviors of some other geophysical parameters should be analyzed in space and time and evaluated carefully.

    AtıfScopus34WoS22OpenAlex28
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  • MakaleYalnız künye2012Scopus SJRQ3
    Statistical correlation between b-value and fractal dimension regarding Turkish epicentre distribution

    Öztürk, Serkan

    This study was aimed at analysing the relationship between seismic b-value and fractal dimension Dc-value for Turkish epicentres. The earthquake catalogue consisting of 99,737 instrumentally-registered Turkish events was analysed for the period between 1970 and 2011; Turkey was divided into 55 tectonic zones for making a detailed comparison. The b-values were calculated by the maximum likelihood method and the Dc-values were obtained with 95% confidence limits by linear regression. The results showed that higher Dc-values were associated with lower b-values and this could have been an indication of relatively high stress intensity and stronger epicentre clustering in these regions. Orthogonal regression was used to estimate a suitable statistical correlation between two seismotectonic parameters; the Dc = 2.44 - 0.30*b relationship was obtained with a strong negative correlation (r = -0.82) between b-value and Dc-value for Turkish earthquake distribution. This seemed to agree with other regional results obtained for different parts of Turkey and the rest of the world.

    AtıfScopus25WoS17
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