An Evaluation of Earthquake Hazard Parameters in and around Ağrı

Abstract

The earthquake hazard parameters of  a and b of Gutenberg-Richter relationships, return periods, expected maximum magnitudes in the next 100 years and probabilities for the earthquakes for certain magnitude values are computed using the earthquakes occurred between 1900 and 2014 years in and around Ağrı.  The relation of LogN=4.73-0.68M is calculated for the studied area.  The mapping of b values show that the regions in the east and southeast of Ağrı, east of Horasan and around Patnos where low b values are computed have high stress levels and capacity to occur large earthquakes in the future. It is found that earthquakes larger than 5.5 may be occurred in the regions where b values lower than 0.8 have been observed in the next 100 years. The return periods for magnitudes between 5.0 and 7.3 are estimated between 5 and 176 years in the studied area.  The probabilities of an earthquake with M=6.0, 6.5 and 7.0 in the next 100 years are computed 99%, 86% and 59%, respectively. The largest earthquake occurred in the studied area is 7.3 and its probability to occur is 43% in the next 100 years.  The faults around Ağrı are seismically active and have potential to an earthquake larger than 6.0. Since the sediment basin of Ağrı is very young and alluvial layer is tick, there is very high hazard on the buildings and human’s life in Ağrı. 

Keywords

• b values
• return period
• expexted maxium
• magnitude
• Ağrı
• Eastern Anatolia

References

1. AKI, K. (1965), Maximum likelihood estimate of b in the formula log N = a - bM and its confidence limits. Tokyo Univ. Bull. Earthq. Res. Inst. 43, 237–239.
2. AMITRANO, D. (2012), Variability in the power-law distribution of rupture events. How and why does b-value change? European Physical Journal Special Topics, 205, 199-215.
3. ASLAN, E. (1972), Magnitude and time distributions of earthquakes in Turkey. Bull Int Inst Seismol Earthq Eng. 7, 1–10.
4. BATH, M. (1979), Seismic risk in Turkey—a preliminary approach. Tectonophysics. 54, 9–16.
5. BAYRAK,Y., YILMAZTÜRK, A., ÖZTÜRK, S. (2005), Relationships between fundamental seismic hazard parameters for the different source regions in Turkey. Nat Hazards. 36, 445–462.
6. BAYRAK, Y., ÖZTÜRK, S., ÇINAR, H., KALAFAT, D., TSAPANOS, T. M., KORAVOS, C. G., LEVENTAKİS, G. A. (2009), Estimating earthquake hazard parameters from instrumental data for different regions in and around Turkey. Eng Geol. 105, 200–210.
7. BAYRAK, Y., ÖZTÜRK, S., ERDURAN, A., (2002), The relationships between maximum magnitudes and modal values for different regions of Turkey. 3rd balkan geophysical congress and exibition 8–4, 24–28 June, Sofia, Bulgaria.
8. BAYRAK, E., YILMAZ, Ş., SOFTA, M., TURKER, T., BAYRAK, Y. (2015), Earthquake hazard analysis for East Anatolian Fault Zone, Turkey, Nat. Hazards, 76, 1063-1077.

9. BOZKURT, E. (2001), Neotectonics of Turkey – a synthesis. Geodinamica Acta. 14, 3-30.
10. ELİTOK, Ö. and DOLMAZ, M. N. (2011), Tectonic Escape Mechanism in the Crustal Evolution of Eastern Anatolian Region (Turkey), New Frontiers in Tectonic Research - At the Midst of Plate Convergence, Dr. Uri Schattner (Ed.), ISBN: 978-953-307-594-5, InTech, Available from: http://www.intechopen.com/books/newfrontiers-in-tectonic-research-at-the-midst-of-plate-convergence/tectonic-escape-mechanism-in-the-crustalevolution-of-eastern-anatolian-region-turkey
11. ERDİK, M., ALPAY, B. Y., ONUR, T., SESETYAN, K., BİRGÖREN, G. (1999), Assesment of earthquake hazard in Turkey and neighboring regions. Ann Geophys. 42, 1125–1138.
12. FROHLICH, C., DAVIS, S. C. (1993), Teleseismic b values; or, much ado about 1.0. J Geophys Res. 98, 631–644.
13. GUTENBERG, R., RICHTER, C. F. (1944), Earthquake magnitude, intensity, energy and acceleration. Bull Seismol Soc Am. 32, 163–191.
14. GOEBEL, T. H. W., SCHORLEMMER, D., DRESEN, G., and BECKER, T. W. (2012), Stress-driven in bv alues during stick-slip on laboratoty fracture granite surfaces. Journal of Geophysical Research. Doi:10.1029
15. KAYABALI, K., AKIN, M. (2003), Seismic hazard map of Turkey using the deterministic approach. Eng GeoL. 69,127–137.
16. LOPEZ, C. C., SANZ DE GALDANO, C., DELGADO, J., PEİNADO, M.A. (1995), The b parameter in the Betic Cordillera, Rif and nearby sectors. Relations with the Tectonics of the region. Tectonophysics. 248, 277–292.
17. MANAKOU, M. V., TSAPANOS, T. M. (2000), Seismicity and seismic hazard parameters evaluation in the island of Crete and the surrounding area inferred from mixed files. Tectonophysics. 321, 157–178.
18. MIYAMURA, S. (1962), Magnitude–frequency relations and its bearing on geotectonics. Proc Jpn Acad. 38, 27–30.
19. MOGI, K. (1962), Magnitude–frequency relationship for elastic shocks accompanying fractures of various materials and some related problems in earthquakes. Bull Earthq Res Inst Univ Tokyo. 40, 831–883.
20. MOGI, K. (1967), Earthquakes and fractures. Tectonophysics. 5, 35–55.
21. MCNALLY, K. C. (1989), Earthquakes and seismicity. In: James DE (ed) The encyclopedia of solid earth geophysics. Springer, 308–315.
22. PACHECO, J., SCHOLZ, C., SYKES, L. (1992), Changes in frequency–size relationship from small to large earthquakes. Nature. 355, 71–73.
23. SCHOLZ, C. H., (1968), The Frequency–magnitude relation of microfracturing in rock and its relation to earthquakes. Bull Seismol Soc Am. 58, 399–415.
24. SCHORLEMMER, D., Wiemer, S., and Wyss, M. (2005), Variations in earthquake size distribution across different stress regimes, Nature. 437, 539–542.
25. SHI, Y., and BOLT, B. A. (1982), The standard error of the magnitude-frequency b-value, Bull. Seismol. Soc. Am. 72, 1677 – 1687.
26. UDIAS, A., MEZCUA, J. (1997), Fundamentos de Geofisica, QE 501. Alianza Editorial, Madrid.
27. WIEMER, S., WYSS, M. (1997), Mapping the frequency–magnitude distribution in asperities: an improved technique to calculate recurrence times. J. Geophys Res, 102, 15115–15128.
28. WIEMER, S., and KATSUMATA, K. (1999), Spatial variability of seismicity parameters in aftershock zones. J. Geophys. Res. 13, 135-151.
29. WIEMER, S. (2001), A software package to analyze seismicity: ZMAP. Seismol Res Lett. 72, 373–382.
30. WIEMER, S., and WYSS, M. (2002), Mapping spatial variability of the frequencymagnitude distribution of earthquakes, Adv. Geophys. 45, 259 – 302.
31. YARAR, R., ERGUNAY, O., ERDİK, M., GULKAN, P. (1980), A preliminary probabilistic assessment of the seismic hazard in Turkey. In: Proceedings of the 7th World conference on earthquake Engineering, Istanbul. 309–316.