ارزیابی بسامد طبیعی خاک در محل احداث پل های غیرهم سطح و مناطق مسکونی در حال توسعه شهر کرمان

نوع مقاله: مقاله پژوهشی

نویسندگان

1 فارغ‌التحصیل کارشناسی ارشد ژئوفیزیک- زلزله شناسی، دانشگاه تحصیلات تکمیلی صنعتی و فناوری پیشرفته، کرمان

2 استادیار ژئوفیزیک– زلزله شناسی، دانشگاه تحصیلات تکمیلی صنعتی و فناوری پیشرفته، کرمان

چکیده

یکی از مسائل مهم در رابطه با تخریب سازه­ها در هنگام وقوع زمین‏لرزه، رفتار خاک روی سنگ بستر است که به­عنوان اثر ساختگاه شناخته می­شود. با توجه به موقعیت شهر کرمان و قرارگیری آن در ایالت لرزه زمین­ساختی ایران مرکزی و شرق ایران و مجاورت آن با چندین گسل از جمله گلباف، سیرچ، نایبند و کوهبنان و همچنین توسعه روزافزون آن، انجام مطالعات به منظور کاهش خسارات زمین‏لرزه ضروری می‌باشد. در این مطالعه، داده‌های میکروترمور در 52 ایستگاه لرزه­سنجی سه­مؤلفه­ای برداشت شده است. جهت در اختیار داشتن داده­هایی با نوفه محیطی کمینه، تمامی برداشت­ها در بازه زمانی 24 تا 5 صبح صورت گرفته است. محدوده­های برداشت، مناطق در حال توسعه شهر کرمان و محل احداث چهار پل مهم در حال ساخت در این شهر را پوشش می‏دهد. با توجه به هدف مطالعه که در حقیقت برآورد بسامد طبیعی و شاخص آسیب‌پذیری زمین می‏باشد، میکروترمور‌های ثبت شده در ایستگاه‏های لرزه‏نگاری با استفاده از روش نسبت طیفی مؤلفه افقی به قائم (H/V) پردازش شدند. مقادیر بسامد در این مناطق بین 3/0 تا 2/1 هرتز تغییر می‌کند. بر اساس بسامد به‌دست‌آمده و مقایسه با جداول استانداردبرای خاک، تمامی ایستگاه‌ها در رده­ ساختگاهی I از نوع خاک سست قرار گرفته­اند. در نهایت، نقشه پهنه‌بندی بسامد و شاخص آسیب‌پذیری رسم شد. نتایج نشان می­دهد که شاخص آسیب­پذیری در محدوده­های طرح توسعه شهر کرمان زیاد می‏باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Soil Natural Frequency Assessment for Planned Grade-Separated Junctions and Under-Development Areas in the City of Kerman

نویسندگان [English]

  • Fatemeh Jahanpoor 1
  • MohammadReza Sepahvand 2
  • Afsaneh Nasrabasdi 2
1 Graduated MSc. of Geophysics, Graduate University of Advanced Technology, Kerman, I. R. Iran.
2 Assistant Professor of Geophysics, Graduate University of Advanced Technology, Kerman, I. R. Iran.
چکیده [English]

One of the important issues in infrastructures' destruction by earthquake is the impact of soil on the bedrock, which is known as “site effect”. Considering the fact that city of Kerman is located in the tectonic seismic state of eastern Iran and is situated near the Golbaf, Koohbanan, Sirch and Nayband faults, it is essential to reduce the dangers of the earthquake. Moreover, one of the most important structures which will be damaged during an earthquake is urban bridges. Thus, in designing the bridges, the impact of earthquake and vulnerability of bridges in places in which earthquake is likely to occur must be taken into consideration. In this study, recorded microtremor data in 52 three-component seismometric stations have been used. To have data with minimum environmental noise, all the measurements were performed in time period of midnight to 5 am in the morning. In this paper, the microtremor data related to the developing areas in Kerman and the erection site of four important bridges which are under construction has been investigated. Considering the objective of the study, which is estimation of the natural frequency and the earth vulnerability index, the recorded microtremors in the seismometric stations were processed using spectral ratio of H/V horizontal to vertical components. Results showed that frequency values vary from 0.3 to 1.2 Hz. Based on the achieved frequencies and comparison to the standard tables, it has been concluded that all the stations are of the soft-soil type in site class I. Finally, the frequency zoning map and vulnerability indices were drawn. Results showed that vulnerability index is high in the developing areas of the city of Kerman

کلیدواژه‌ها [English]

  • Earthquake
  • Site effects
  • Microtremor
  • H/V method

حسن‌زاده، ر.، عباس‌نژاد، ا.، علوی، ا. و شریفی، ا. 1390. "تحلیل خطر لرزه‌ای شهر کرمان با تأکید بر کاربرد GIS در ریز‌پهنه‌بندی مقدماتی درجه 2". علوم زمین، 81: 23-30.

Asten, M.W. 1978. “Geological control of the three-component spectra of Rayleigh-wave microseismic”. Bull. Seismol. Soc. Am., 68(6): 1623-1636.

Bard, P.Y. 1999. “Microtremor measurements: A tool for site effect estimation?” Proceedings of the Second International Symposium on the Effects of Surface Geology on Seismic Motion, 3: 1251-1279.

Borcherdt, R.D. 1970. “Effects of local geology on ground motion near San Francisco Bay”. Bull. Seismol. Soc. Am., 60: 29-61.

Chen, Q.F., Liu, L.B., Wang, W.J. and Rohrbach, E. 2009. “Site effects on earthquake ground motion based on microtremor measurements for metropolitan Beijing”. Chinese Sci. Bull., 54(2): 280-287.

Flores, H., Malischewsky, P. and Jentzsch, G. 2013. “H/V spectral ratio analysis and Rayleigh modelization in Eastern Thuringia, Germany”. Geofísica Internacion, 52(4): 355-364.

Gutenberg, B. 1958. “Microseisms”. Adv. Geophy., 5: 53-92.

Hashemi, H., Eskandarpour, M.R., Adib, D.R. and Fatemi Aghda, D.R. 2007. “A case study of microtremor analysis in Baneh city for the purpose of seismic hazard estimation”. EAGE 69th Conference and Exhibition.

Kazemi, A.M. and Adib, A. 2014. “Geotechnical zoning and determining land types by microteremor: A case study of Ardakan, Yazd, Iran”. Geodyn. Res. Anal. Int. Quart. Bull., 2(1): 11-18.

Komak­ Panah, A., Hafezi Moghaddas, N., Ghayamghamian, M.R., Motosaka, M., Jafari, M.K. and Uromieh, A. 2002.  “Site effect classification in east-central of Iran”. J. Seismol. Earthq. Eng., 4(1): 37-48.

Mac Murdo, J. 1824. “Papers relating to the earthquake which occurred in India in 1819”. Philos. Mag., 63: 105-177.

Massa, M., Lovati, S., Marzorati, S. and Augliera, P. 2011. “Seismic ground amplifications estimated by means of spectral ratio techniques: Examples for different geological and morphological settings”. Earth Environ. Sci., Doi:10.5772/27766.

Mirzaei, N., Mengtan, G. and Yuntai, C. 1998. “Seismic source regionalization for seismic zoning of Iran: Major seismotectonic provinces”. J. Earthq. Predic. Res., 7: 465-495.

Mirzaoglu, M. and Dykmen, U. 2003. “Application of microtremors to seismic microzoning procedure”. J. Balkan Geophys. Soc., 6: 143-156. 

Mucciarelli, M. and Gallipoli, M.R. 2001. “A critical review of 10 years of microtremor HVSR technique”. Boll. di Geofisica Teorica Applicata, 42: 255-266.

Nakai, S.H. and Nakagawa, H. 2011.“Wave propagation analysis of a ground with three-dimensional irregularities based on the finite element method”. 4th IASPEI/IAEE International Symposium.

Nakamura, Y. 1989. “A method for dynamic characteristics estimation of subsurface using microtremor on the ground surface [Internet]. Q. Rep. Railw. Tech. Reasearch Inst., pp. 25-33.

Nakamura, Y. 1997. “Seismic vulnerability indices for ground and structures using microtremor”. World Congress on Railway Research, Florence.

Nakamura, Y. 2000. “Clear identification of fundamental idea of Nakamura's technique and its applications". 12th WCEE, www.sdr.co.jp/papers/n_tech_and_application.pdf.

Nakamura, Y. 2008a. “Characteristics of H/V spectrum”. www.researchgate.net/publication/268381223.

Nakamura, Y. 2008b. “On the H/V spectrum”. The 14th World Conference on Earthquake Engineering, Beijing, China.

Nogoshi, Y. and Igarashi, T. 1971. “On the amplitude characteristics of microtremor (part 2). J. Seis. Soc. Jap. 24: 26-40.

Omori, F. 1908. “On microtremor”. Res. Imp. Earthq. Inv. COMM., 6: 1-6.

Pitilakis K. 2007. “Earthquake Geotechnical Engineering”. 4th International Conference on Earthquake Geotechnical Engineering- Invited Lectures, Series: Geotechnical, Geological and Earthquake Engineering, The Netherlands, pp. 93-129.

Reid, H.F. 1910. “The mechanics of the earthquake”. Vol. II of Lawson, A.C., chairman, The California earthquake of April 18, 1906, Report of the State Earthquake Investigation Commission, Carnegie Institution of Washington, Publication 87, 192 p.

Rinne, E.E. 1994. “Development of new site coefficients for building codes”. Proceeding of the Fifht US National Conference on Earthquake Engineering, Chicago, 3: 64-78.

Roca, A., Oliveira, C.S., Ansal, A. and Figueras, S. 2008. “Local site effects and microzonation”. In: Oliveira, C.S., Roca, A. and Goula, X. (Eds.), Assessing and Managing Earthquake Risk, Geotechnical, Geological and Earthquake Engineering, Vol. 2, Springer, Dordrecht.

Talha Qadri, S.M., Nawaz, B., Sajjad, S.H. and Ahmad Sheikh, R. 2015. “Ambient noise H/V spectral ratio in site effects estimation in Fateh Jang area, Pakistan”. Earthq. Sci., 28(1): 87-95.

Tezcan, S.S., Kaya, E., Bal, I.E. and Ozdemir, Z. 2002. “Seismic amplification at Avcilar, Istanbul”. Eng. Struc., 24(5): 661-667.

Theilen-Willige, B. 2010. “Detection of local site conditions influencing earthquake shaking and secondary effects in Southwest-Haiti using remote sensing and GIS-methods”. Nat. Haz. Earth Sys. Sci., 10: 1183-1196.

Wenbo, Z.H. and Koji, M.A. 2000. “Comparison of site-amplification estimated from different methods using a strong motion observation array in Tangshan”. WCEE, China.

Wood, H.0. 1908. Distribution of apparent intensity in San Francisco, in the California earthquake of April 18, 1906. Report of the State Earthquake Investigation Commission: Carnegie Inst. Washington Pub. 87, Washington, D.C., pp. 220-245.