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بررسی پارامتر لرزهخیزی b-value و بعد فرکتال لرزهخیزی (Dc-value) در زون برخوردی زاگرس | ||
| فیزیک زمین و فضا | ||
| مقاله 2، دوره 52، شماره 1، خرداد 1405، صفحه 17-31 اصل مقاله (1.65 M) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22059/jesphys.2026.402700.1007725 | ||
| نویسندگان | ||
| محمد حسین موسوی1؛ پروا صادقی علویجه2؛ امیر طالبی* 3؛ محمد کرمی4 | ||
| 1گروه آموزش فیزیک، دانشگاه فرهنگیان، تهران، ایران. | ||
| 2گروه فیزیک، دانشکده علوم پایه، دانشگاه کاشان، کاشان، ایران. | ||
| 3گروه فیزیک، دانشکده علوم پایه، دانشگاه اراک، اراک، ایران. | ||
| 4گروه فیزیک زمین، مؤسسه ژئوفیزیک، دانشگاه تهران، تهران، ایران. | ||
| چکیده | ||
| کمربند کوهزایی زاگرس، واقع در محل تلاقی ایران مرکزی و صفحه عربستان، به عنوان یکی از فعالترین مناطق لرزهخیز از نظر رکوردهای تکتونیکی، زمینلرزه، ژئوفیزیکی و زمینشناختی در ایران شناخته میشود. این پژوهش با بهرهگیری از الگوریتم خوشهبندی توسعهیافته ارهامر(اورهامر1986) به بررسی تغییرات مکانی-زمانی بر اساس پارامترهای b-value و Dc-value برای زمینلرزههای رخداده در پهنه موردنظر میپردازد. کاتالوگ زمینلرزه زمینلرزههای مورد استفاده در این پژوهش شامل بیش از 40,000 رویداد با بزرگی بیش از 5/1 است که از سال 2006 تا 2024 توسط مرکز لرزهنگاری ایران (IRSC) ثبت شدهاند. یافتهها نشان میدهد که b-value در زون گسیختگی زاگرس در مناطق شمالی و جنوبی نوسان دارد و تحتتأثیر رویدادهای زمینلرزهای منفرد است. توزیع مکانی b-value مقدار بیشتر را در زاگرس شمالی نسبت به مناطق جنوبی، با مقادیری بین 5/0 تا 5/1 نشان میدهد. با اینحال، زلزله سرپلذهاب با بزرگی 3/7 در زاگرس شمالی نشان میدهد که بزرگترین رویدادهای اخیر در بخش شمالی ناحیه رخ داده است. این امر میتواند ناشی از تفاوت در نرخ همگرایی، ضخامت رسوبات، یا مکانیسم گسلی در شمال و جنوب ناحیه برخوردی زاگرس باشد. بنابراین، تجمع تنش در زاگرس جنوبی همچنان پابرجاست، اما پتانسیل آزادسازی آن بهصورت رویدادهای متوسط تا بزرگ بیشتر از وقوع رویدادهای خیلی بزرگ است. تحلیل زمانی b-value همچنین همبستگی بین کاهش b-value و وقوع رویدادهای مهم زمینلرزهای (با بزرگی بیش از 6) را نشان میدهد. علاوه بر این، ما تغییرات Dc-value (6/1-2) را برای شناسایی تغییرات در ساختار گسل محاسبه کردهایم. Dc-value همبستگی معکوس با b-value را نشان میدهد، با نزدیک شدن گسل به شکست، انرژی آزاد شده از تجمع تنش با افزایش Dc-value مشخص میشود. هدف این مطالعه ارائه یک دید کلی و جامع از فعالیتهای تکتونیکی همراه با تغییرات در b-value و Dc-value در زون مورد مطالعه است، که از این طریق درک ما را از توزیع تنش بهبود میبخشد. یافتهها نشان داد که b-value و Dc-value میتوانند بهعنوان شاخصهای بالقوه افزایش خطر لرزهای در زون عمل کنند. | ||
| کلیدواژهها | ||
| زاگرس؛ لرزه زمین ساخت؛ b-value؛ Dc-value | ||
| عنوان مقاله [English] | ||
| Analysis of Seismicity Parameters b-value and Fractal Dimension (Dc-value) in the Zagros Collision Zone | ||
| نویسندگان [English] | ||
| Muhammed Hossein Mousavi1؛ Parva Sadeghi Alavijeh2؛ Amir Talebi3؛ Mohammad Karami4 | ||
| 1Department of Physics Education, Farhangian University, Tehran, Iran. | ||
| 2Department of Physics, Faculty of Science, University of Kashan, Kashan, Iran. | ||
| 3Department of Physics, Faculty of Science, Arak University, Arak, Iran. | ||
| 4Department of Earth Physics, Institute of Geophysics, University of Tehran, Tehran, Iran. | ||
| چکیده [English] | ||
| The Zagros Fold-and-Thrust Belt (ZFTB), as one of Iran's most active seismic zones, is situated at the convergent boundary between the Arabian Plate and the Central Iranian Block. Characterized by a high convergence rate, complex tectonic structures, and a rich seismic history, it has consistently been a focal point for tectonic and seismological research. This study aims to provide a comprehensive spatiotemporal analysis of the seismic indices b-value and Dc-value within this region, utilizing the earthquake catalog compiled by the Iranian Seismological Center (IRSC) from January 2006 to November 2024. The catalog, containing over 40,000 events with magnitudes greater than 1.5, served as the basis for analysis after refinement and removal of duplicate data. The b-value was estimated using the Gutenberg-Richter relationship coupled with the maximum likelihood method. To investigate structural changes in faults, the Dc-value parameter was also calculated. Event clustering was performed using an enhanced version of the Uhrhammer algorithm to optimally distinguish seismic clusters and remove aftershocks and foreshocks from the dataset. Spatial results revealed significant heterogeneity in the b-value across the Zagros, with values in the southern Zagros being substantially lower (0.25–0.55) on average compared to the central and northern sections. This pattern indicates higher stress concentration and a greater potential for larger earthquakes in the southern Zagros. In contrast, the higher b-values in the northern parts may reflect smaller-scale fracturing and more distributed stress. Temporal analysis of the b-value demonstrated a significant decrease during specific periods, particularly preceding large earthquakes (Mw > 6). A prominent example of this behavior was recorded before the Mw 7.3 Sarpol-e Zahab earthquake (2017), where the b-value decreased from approximately 0.85–1.0 to about 0.55–0.7 during the foreshock stage. This drop could be attributed to increased stress concentration, changes in fracture density, or crustal fluid migration, suggesting its potential as a possible precursor signal. During the co-seismic stage of this event, the lowest b-values (0.6) coincided with the main rupture, reflecting the sudden and intense stress release along the High Zagros Fault zone. In the post-seismic phase following the mainshock, a trend of relative b-value (1.2) recovery was observed, likely resulting from tectonic relaxation processes, stress redistribution, and aftershock activity. Analysis of the Dc-value, which expresses the correlation length of fractures and fault structure, revealed a complementary pattern to the b-value. Regions with low b-values exhibited higher Dc-values (1.6-2). This inverse correlation suggests that as a fault approaches its ultimate rupture stage, the fracture structure becomes more coherent and correlated, with energy release concentrating on larger scales. The combined spatiotemporal results for the b-value and Dc-value provide a comprehensive picture of the stress state and seismic dynamics of the Zagros. These findings indicate that a decrease in b-value accompanied by an increase in Dc-value can be considered a warning pattern for elevated seismic hazard. If confirmed by independent data over longer timeframes, such a pattern could be integrated into seismic monitoring systems and earthquake hazard assessment frameworks for Iran. From a tectonic perspective, the spatial heterogeneity of the b-value and Dc-value reflects differences in convergence rates, fault geometry, crustal rheological properties, and the role of hydrothermal processes in different segments of the Zagros. The southern Zagros, with its higher convergence rate and presence of long, active faults such as the MFF (Mountain Front Fault) and MZF (Main Zagros Fault), is prone to stress concentration and larger events, whereas the northern and central parts, with more complex structures and distributed fracturing, exhibit a different pattern of seismicity. In summary, this study, employing advanced statistical analyses and seismic clustering, has established a significant correlation between variations in b-value and Dc-value and the active tectonic processes in the Zagros. The obtained results not only contribute to a better understanding of stress distribution and seismic dynamics in this region but also provide a basis for developing predictive seismic hazard models and designing risk mitigation strategies for high-risk areas in Iran. | ||
| کلیدواژهها [English] | ||
| Zagros, seismotectonic, b-value, Dc-value | ||
| مراجع | ||
|
Agard, P., Omrani, J., Jolivet, L., Whitechurch, H., Vrielynck, B., Spakman, W., & Wortel, R., (2011). Zagros orogeny: a subduction-dominated process. Geological Magazine, 148(5-6), 692-725.doi: 10.1017/S001675681100046X. Ahadov, B., & Ozturk, S. (2021). Spatial Variations of B-Value and Fundamental Parameters of the Earthquake Occurrences in The Eastern Mediterranean and Caucasus. Aki, K. (1965). Maximum likelihood estimate of b in the formula log N= a-bM and its confidence limits. Bull. Earthquake Res. Inst., Tokyo Univ., 43, 237-239. Aki, K. (1984). Asperities, barriers, characteristic earthquakes and strong motion prediction. Journal of Geophysical Research: Solid Earth, 89(B7), 5867-5872. Bahroudi, A., & Koyi, H. A. (2003). Effect of Hormuz salt layer on the structure and seismicity of the Zagros fold and thrust belt, Iran. Journal of the Geological Society, 160(5), 809-819. Diehl, T., Lee, T., Houlié, N., Cardello, G. L., Kraft, T., Clinton, J., & Wiemer, S. (2017). Multidisciplinary insights into the seismotectonics of the Swiss Alps and its foreland. In EGU General Assembly Conference Abstracts (p. 14456). Farahi Ghasre Aboonasr, S., Zamani, A., Razavipour, F., & Boostani, R. (2017). Earthquake hazard assessment in the Zagros Orogenic Belt of Iran using a fuzzy rule-based model. Acta Geophysica, 65(4), 589-605. Gardner, J. K., Knopoff, L. (1974). Is the sequence of earthquakes in Southern California, with aftershocks removed, Poissonian? Bull Seismol Soc Am, 64(5), 1363–1367 Grassberger, P., Procaccia, I. (1983). Measuring the strangeness of strange attractors. Physica D, 9(1–2), 189–208. Gutenberg, B., & Richter, C. F. (1944). Frequency of earthquakes in California. Bulletin of the Seismological society of America, 34(4), 185-188. Hatzfeld, D., Tatar, M., Priestley, K., & Ghafory-Ashtiany, M. (2003). Seismological constraints on the crustal structure beneath the Zagros Mountain belt (Iran). Geophysical Journal International, 155(2), 403-410. doi:10.1046/j.1365-246X. 2003.02045.x Jahani, S., Callot, J. P., Letouzey, J., Leturmy, P., & Müller, C. (2009). The salt diapirs of the Iranian offshore domains (Persian Gulf): Interaction with regional shortening and implications in petroleum geology. Tectonophysics, 471(1-2), 13-36. James, G. A., & Wynd, J. G. (1965). Stratigraphic nomenclature of Iranian oil consortium agreement area. AAPG bulletin, 49(12), 2182-2245. Kayal, J. R. (2010). Himalayan tectonic model and microearthquake activity. Geological Society of India. Kent, P. E. (1979). The emergent Hormuz salt plugs of southern Iran. Journal of Petroleum Geology, 2(2), 117-144 Madahizadeh, R., Mostafazadeh, M., & Ashkpour-Motlagh, S. (2016). Evaluation of Earthquake Potential in the Zagros Region (Iran) Using Seismic Strain and Seismicity Parameters. Journal of Seismology and Earthquake Engineering, 18(4), 199-218. doi: 10.1515/acgeo-2016-0080. McQuarrie, N. (2004). Crustal scale geometry of the Zagros fold–thrust belt, Iran. Journal of Structural Geology, 26(3), 519-535. Mousaviyan, S., & Mostafazadeh, M. (2025). Evaluation of seismic stress changes in the northern part of the Zagros in Iran. Acta Geophysica, 1-23 .doi: 10.1007/s11600-024-01489-y. Mouthereau, F., Lacombe, O., & Vergés, J. (2012). Building the Zagros collisional orogen: timing, strain distribution and the dynamics of Arabia/Eurasia plate convergence. Tectonophysics, 532, 27-60. doi: 10.1016/j.tecto.2012.01.022. Mukhopadhyay, B., & Sengupta, D. (2018). Seismic moment release data in earthquake catalogue: application of Hurst statistics in delineating temporal clustering and seismic vulnerability. Journal of the Geological Society of India, 91(1), 15-24 Nankali, H. R. (2011). Distribution of earthquakes and stress state in the Zagros fold-thrust1001 belt. Journal of Geodynamics, 51(4), 271-278. Nazarinezhad, Z., Sepahvand, M., & Nasrabadi, A. (2024). Seismotectonic investigation in northwest Zagros, Iran: analysis of Ezgeleh Mw 7.3 aftershocks. Journal of Seismology, 28(1), 81-101. doi: 10.1007/s10950-023-10184-2. Öztürk, S. (2015). A study on the correlations between seismotectonic b-value and Dc-value, and seismic quiescence Z-value in the Western Anatolian region of Turkey. Austrian Journal of Earth Sciences. doi: 10.17738/ajes.2015.0019. Paul, A., Kaviani, A., Hatzfeld, D., Vergne, J., & Mokhtari, M. (2006). Seismological evidence for crustal-scale thrusting in the Zagros mountain belt (Iran). Geophysical Journal International, 166(1), 227-237. Roumina, A., Zarei, S., Mansouri, S. R., & Azadijou, O. (2023). Seismic distribution in the south of Zagros using the statistical correlation between b-Value and fractal dimension. Iranian Journal of Geophysics, 17(1), 89-107. Schorlemmer, D., Wiemer, S., & Wyss, M. (2005). Variations in earthquake-size distribution across different stress regimes. Nature, 437(7058), 539-542. Stöcklin, J., 1968. Structural history and tectonics of Iran: a review. AAPG Bulletin, 52(7), 1229-1258. Talebi, A., Koulakov, I., Moradi, A., Rahimi, H., & Gerya, T. (2020). Ongoing formation of felsic lower crustal channel by relamination in Zagros collision zone revealed from regional tomography. Scientific reports, 10(1), 8224. Tormann, T., Wiemer, S., & Mignan, A. (2014). Systematic survey of high‐resolution b value imaging along Californian faults: Inference on asperities. Journal of Geophysical Research: Solid Earth, 119(3), 2029-2054. Utsu, T. (1972). Aftershocks and earthquake statistics (4): Analyses of the distribution of earthquakes in magnitude, time and space with special consideration to clustering characteristics of earthquake occurrence (2). Journal of the Faculty of Science, Hokkaido University. Series 7, Geophysics, 4(1), 1-42. Wyss, M. (1997). Second round of evaluations of proposed earthquake precursors. Pure Appl Geophys, 149, 3–16 Wiemer, S., & Wyss, M. (2002). Mapping spatial variability of the frequency-magnitude Distribution of earthquakes. In Advances in geophysics, Elsevier, 45, 259-V). | ||
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