A STUDY ON THE CHARACTERISTICS OF GÜMÜŞHANE SEISMICITY: ANALYSES OF REGION-TIME PARAMETERS

The proposed study is focused on the identification of region-time characteristics of earthquakes in Gümüşhane, Turkey. Detailed statistical evaluations were achieved by considering the most frequently used size-scaling parameters such as seismotectonic b-value, fractal dimension Dc-value, standard normal deviate Z-value and recurrence time of earthquakes. Used earthquake catalog is homogeneous for duration magnitude, Md, and consists of 2902 shallow earthquakes with 1.0≤Md≤6.5 in about 47.76-years period between 1970 and middle of 2018. b-value is computed as 1.02±0.02 with a completeness level of 2.8, and this result indicates that frequency-magnitude distribution of seismicity in Gümüşhane is well represented with a b-value typically close to 1.0. Dc-value is calculated as 1.57±0.03 with a scale invariance between 4.96 and 86.28 km. This Dc-value means that seismic activity is more clustered in smaller areas or at larger scales in Gümüşhane. The analysis on the recurrence times of earthquakes implies that Gümüşhane has not a significant earthquake potential for the great earthquakes. Regional variation of b-value shows that small b-values were observed in and around Kelkit and Köse, and these regions may have a possible earthquake hazard and risk in the future. Z-value analysis suggests that there are not noticeable seismicity rate changes in the mid-2018. These statistical results indicate that the seismic hazard is low and seismic risk is minor in the intermediate term in Gümüşhane.

Keywords:

Gümüşhane, seismicity, statistics seismic hazard, seismic risk.,

PDF

___

[1] Hirata T. (1989) Correlation between the b-value and the fractal dimension of earthquakes, J. Geoph. Res., vol. 94, no. B6, pp. 7507-7514.
[2] Frohlich C., and Davis S. (1993) Teleseismic b-values: Or, much ado about 1.0, J. Geoph. Res., vol. 98, no. B1, pp. 631-644.
[3] Awad H., Mekkavi M., Hassib G., and Elbohoty M. (2005) Temporal and three dimensional spatial analysis of seismicity in the Lake Aswan area, Egypt, Acta Geoph. Pol., vol. 53, no. 2, pp. 152-166.
[4] Polat O., Gok E., and Yılmaz D. (2008) Earthquake hazard of the Aegean extension region (west Turkey), Turkish J. Earth Sci., vol. 17, no. 3, pp. 593-614.
[5] Öztürk S. (2011) Characteristics of seismic activity in the western, central and eastern parts of the North Anatolian Fault Zone, Turkey: Temporal and spatial analysis, Acta Geoph., vol. 59, no.2, pp. 209-238.
[6] Öztürk S. (2017) Space-time assessing of the earthquake potential in recent years in the Eastern Anatolia region of Turkey, Earth Sci. Res. J., vol. 21, no. 2, pp. 67-75.
[7] Gutenberg R., and Richter C. F. (1944) Frequency of earthquakes in California, BSSA, vol. 34, no. 4, pp. 185-188.
[8] Mandelbrot B. B. (1982) The fractal geometry of nature”, Freeman Press, San Francisco.
[9] Wiemer S., and Wyss M. (1994) Seismic quiescence before the Landers (M=7.5) and Big Bear (6.5) 1992 earthquakes, BSSA, vol. 84, no. 3, pp. 900-916.
[10] Kumazawa T., Ogata Y., and Toda S. (2010) Precursory seismic anomalies and transient crustal deformation prior to the 2008 Mw = 6.9 Iwate-Miyagi Nairiku, Japan, earthquake, J. Geoph. Res., vol. 115, no. B10, pp. 1-19.
[11] Öztürk S. (2018) Earthquake hazard potential in the Eastern Anatolian part of Turkey: seismotectonic b and Dc-values, and precursory quiescence Z-value, Frontiers of Earth Sci., vol. 12, no. 1, pp. 215-236.
[12] Wyss M., and Habermann R. E. (1988) Precursory seismic quiescence, PAGEOPH, vol. 126, no. 2-4, pp. 319-332.
[13] Taş N., Okumuş E., Öner Ş., Köksal C., İcat M. Y., Tanış S., and Aslan N. (2003) Gümüşhane il çevre durum raporu, 179 sayfa, Gümüşhane Valiliği İl Çevre ve Orman Müdürlüğü, Gümüşhane.
[14] Reilinger R. E., McClusky S. C., Oral M. B., King W., and Toksöz M. N. (1997) Global Positioning System measurements of present-day crustal movements in the Arabian-Africa-Eurasia plate collision zone, J. Geoph. Res, vol. 102, no. B5, pp. 9983-9999.
[15] Bozkurt E. (2001) Neotectonics of Turkey-a synthesis, Geod. Acta, vol. 14, no. 1-3, pp. 3-30.
[16] Öztürk S. (2017) Gümüşhane ve Civarındaki Güncel Deprem Aktivitesinin Bölgesel ve Zamana Bağlı Değişimleri: İstatistiksel Bir Değerlendirme, Gümüşhane Üniversitesi Fen Bilimleri Enstitüsü Dergisi, vol. 7, no. 1, pp. 25-40.
[17] Şaroğlu F., Emre O., and Kuşçu I. (1992) Active fault map of Turkey, General Directorate of Mineral Research and Exploration, Ankara, Turkey.
[18] Gutenberg R., and Richter C. F. (1944) Frequency of Earthquakes in California, BSSA, vol. 34, no. 4, pp. 185-188.
[19] Utsu T. (1971) Aftershock and Earthquake Statistic (III): Analyses of the Distribution of Earthquakes in Magnitude, Time and Space with Special Consideration to Clustering Characteristics of Earthquake Occurrence (1), J. of Faculty of Sci., Hokkaido Univ., Series VII (Geophysics) vol. 3, no. 5, pp. 379-441.
[20] Grassberger R., and Procaccia I. (1983) Measuring the Strangeness of Strange Attractors, Physica, vol. 9, no. 1-2, pp. 189-208.
[21] Öncel A. O., and Wilson T. H. (2002) Space-time correlations of ceismotectonic parameters and examples from Japan and Turkey preceding the İzmit earthquake, BSSA, vol. 92, no. 1, pp. 339-350.
[22] Wimer S. (2001) A software package to analyze seismicity: ZMAP, Seismol. Res. Lett., vol. 72, no. 2, pp. 373-382.
[23] Wiemer S., and Wyss M. (2000) Minimum magnitude of completeness in earthquake catalogs: Examples from Alaska, the Western United States, and Japan, BSSA, vol. 90, no. 3, pp. 859-869.
[24] Reasenberg P. A. (1985) Second-order moment of central California seismicity, 1969-1982, J. Geoph. Res., vol. 90, no. B7, pp. 5479-5495.
[25] URL-1. http://www.mta.gov.tr/mta_web/haritalar.asp, 26/12/2007.