Neotectonic Performance Review on Alluvial Fans, with Emphasis on Seismic Power Fault (Case Study: Northwest slopes of Sahand Mountain)

Document Type : Research Article

Authors

• Aghil Madadi ¹
• Davod Mokhtari ²
• Hamdieh Shirzadi ²
• Arsalan Mehrvarz ³

¹ University of Mohaghegh Ardabili

² University of Tabriz

³ mohaghegh ardabili

10.22067/geo.v5i2.51671

Abstract

1. Introduction
The Earth's crust is composed of various landforms. These forms are constantly changing. In this change, both of internal and external factors have a decisive role. The Internal factors led to the formation of the primary structure and external factors that cause erosion, deformation and destruction of these forms. Areas that have been affected by these activities confronted by various geomorphological forms, the alluvial fans were formed by different causes in this highlands. This study is an attempt to study the influence of tectonic on the formation and development of alluvial fans in the northwestern slopes of Sahand, calculate the seismic generating power of faults, and evaluate the seismic zoning of the risk arising from fault position on the alluvial fans and human activities. Sahand Mountain is located in the northwestern Iran with a geographical coordination of 37°07'to 38°02' North and 45°53' to 47°00' East. The total area of alluvial fans is 29.874297 square kilometers. This massive mountainous acreage covers an area of 8,000 square kilometers.
2. Material and Methods
In this study, 1: 25,000 maps of National Cartographic Center were used as the basic maps to identify tophographical units and location of alluvial fans. The geological map of 1: 100,000 were used to identify faults and geological formations of the region. Aerial photos of 1: 50,000, 1: 40000.1: 20000, from this area as well as satellite images were used in the completion of studies. After identifying alluvial fans and their initial review of the documents, the seismic data of the area was collected. Fault zones were detected by studying available geological maps, and their most important ones were drawn to the field of satellite imagery. Then, the seismic characteristics of the region were analyzed and a list of earthquakes were collected in radial expansion of 300 kilometers .The seismic potential of active faults from the initial parameters related to earthquake risk assessment were calculated using zarei, Ashjaei and Navrozi's formulas.
3. Results and Discussion
The impact of tectonic activity in the form of alluvial fans were analyzed by these indicators: the effects of tectonic on alluvial fans using the index Vf ; calculation of Vf on the alluvial fans of the area shows that only two alluvial fans (6 and 7) of the index are between 1-2 and other alluvial fans index are smaller than 1. The effects of tectonics on alluvial fans using the curvature index: the results of the study show that the alluvial fans of numbers 2, 3, 5, 9 have the smallest curvature coefficient and alluvial fans 6, 7 and 10 have gained the largest amount of curvature coefficient.
4. Conclusion
According to the results of this study that indicates tectonic activity status (fault) on the surface of the alluvial fans, high seismic potential of faults represent a high risk arising activity of faults in the surface of alluvial fans. Hence, any activity in the alluvial fans (build settlements, communication lines, construction projects, etc.) needs preparation and special considerations so that the losses of the operation can be reduced to a minimum. Values obtained indicate that the role of tectonic activity in the region has been higher on the alluvial fan because of the proximity of the large faults in the studied area. 2 faults in the region have the highest longitude. The risk of these faults are threatening Tabriz and Khosrowshahr cities with widespread devastation.

Keywords

• Tectonic
• alluvial fan
• earthquakes
• the slopes of Mountian Sahand

---

References

پورکرمانی، محسن؛ آرین، مهران؛ 1376. سایزموتکتونیک، شرکت مهندسی مشاور در آب. شماره63. صص 69-55.

رجبی، معصومه؛ آقاجانی، کامیلا؛ ۱۳۸۹. بررسی گسل‌ها، توان لرزه‌زایی و خطر زمین‌لرزه در مخروط افکنه‌های شمال شرق دریاچه ارومیه. فصلنامه جغرافیای طبیعی. سال سوم. شماره۷. صص ۱۴-۱.

رضایی مقدم، محمدحسین؛ 1374. پژوهشی در تشکیل کوهپایه‌ها و دشت‌های انباشتی دامنۀ جنوبی میشوداغ. پایان نامه دکتری. استاد راهنما: مقصود خیام، دانشکده علوم انسانی و اجتماعی، دانشگاه تبریز. صص 180-1.

روستایی، شهرام؛ زمردیان، محمدجعفر؛ رجبی، معصومه؛ مقامی مقیم، غلامرضا؛ ۱۳۸۸. نقش فعالیت‌های تکتونیکی در شکل‌گیری و گسترش مخروط افکنه‌های دامنه جنوبی الاداغ. مجله جغرافیا و توسعه. شماره۱۳. صص۱۵۶-۱۳۷.

شایان، سیاوش؛ زارع، غلامرضا؛ ۱۳۹۲. تعیین محدوده خطر زمین لرزه در مخروط افکنه های فعال با روش تحلیل فضایی بربریان (مطالعه موردی مخروط افکنه گرمسار. مدرس علوم انسانی- برنامه ریزی و آمایش فضا. دوره هفدهم. شماره۲. صص120-93.

شرکت صحراکاو؛ 1380. مطالعات ژئوالکتریک دشت هادیشهر. سازمان منابع آب استان آذربایجان شرقی، طرح مطالعاتی سازمان آب و فاضلاب استان آذربایجان شرقی. شماره34. صص 33-23.

شریفی کیا، محمد؛ افضلی، عباسعلی؛ 1391. پایش و تحلیل روند افزایش شوری خاک در مخروط افکنه دامغان با استفاده از تکنیک‌های سنجش از دوری و داده‌های پیمایش. مجله مخاطرات مشهد. سال اول. شماره 3. صص87-73.

عابدینی، موسی؛ رجایی، عبدالحمید؛ ۱۳۸۵. بررسی نقش عوامل مؤثر در گسترش و تکامل مخروط افکنه‌های ارتفاعات دره دیز-دیوان داغی بااستفاده از روش‌ها و تکنیک‌های جدید. فصلنامه پژوهش جغرافیایی. شماره ۵۵. صص ۸۹-۷۳.

عباس نژاد، احمد؛ 1376. بررسی نوزمین ساختی مخروطه افکنه های ناحیه کرمان، علوم زمین، شماره26-25.

مختاری، داود؛ خیام، مقصود؛ ۱۳۸۲. ارزیابی عملکرد فعالیت تکتونیکی بر اساس مرفولوژی مخروط افکنه‌ها دامنه شمالی میشو داغ. فصلنامه پژوهش‌های جغرافیایی. شماره ۴۴. صص ۱۰-۱.

موسوی حرمی، رضا؛ 1377. رسوب شناسی، انتشارات آستان قدس رضوی. چاپ پنجم. صص1-474.

Andrey Korjenkov., 2004. Morphological response through competing of thrusting and erosion, at basin foothills, the northern Tien Shan, Kyrghyzstan. 268, 50-70.

Bull W. B. and L. D. McFadden., 1977. Tectonic geomorphology of north fault, California in: Doehring, geomorphology of arid regions. Allen and Unwin. London.

Drew,f., 1873.Alluvial and lacustrine deposits and glacial records of the upper Indusbasin,Quarterly Journal of the Geological Society of London, 29, 441-471.

Hooke, R. L., 1972. Geomorphic evidence for lateWisconsin and Holocene tectonicdeformation in Death vally,California.Geological Socity of America Bulletin, 83,2073-2098.

Huggett,r.j., 2003. Fundamaental of geomorphology.Routledge.

Mcpherson,H.J. AND Hirst, F (1972. Sediment changes on two Alluvial fans in the CanadaianCordillerra British Columbia, 14, 161-172.

Mukerji, A. B., 1976. Terminal fans of inlands streams insutlej-yamuna plain, india, zeitschrift fur Geomorphology, 20, 190-204.

Ramirrez-Herrera, M .T., 1998. Geomorphic assessment of active tectonics in the Acambaygarban, Mexican Volcanic belt. Earth surface process and landforms. 23,452.pp 317-322.

Rockwell, T. k. et. Al., 1984. alatePleistocence- Holocence soil chronosquence in theventura basin southern California u.s.aallen and unwin, 16 .476.309-327.