Liquefaction Hazard assessment using Horizontal-to-Vertical Spectral Ratio of Microtremor

Subject Areas : Structural Engineering

Mehdi  Mokhberi ¹ (Department of civil engineering, Estahban Branch, Islamic azad University, Shiraz , Iran)
Sadegh  Yazdanpanah Fard ² (bDepartment of civil engineering, Estahban Branch, Islamic azad University, Estahban, Iran)

Received: 2018-07-23 Accepted : 2018-11-29 Published : 2018-09-01

Keywords: Soil liquefaction, microtremor HVSR, predominant frequency, amplification factor, vulnerability index,

Abstract :

In this paper, the spectral ratio of mmicrotremor, HSVR, is presented for estimating the liquefaction potential of layered soil in the coastal area of the Persian Gulf, which consists of a hard sandstone layer situated between two saturated sandy layers. The surface layer is thin, with a thickness between 2 and 5 meters. The purpose of this paper is to identify the relation between the liquefaction potential, the natural frequency and the amplification factor values using microtremors. Liquefaction assessment was done at 27 stations using the HVSR approach provided by Nakamura [1]. HVSR analysis was carried out using the Geopsy software. According to the results of the analysis, the predominant frequency values range from about 0.8 Hz to 2.4 Hz and the amplification factor values range from 1.1 to 2.8. Based on these parameters, the vulnerability index Kg is determined, which can be used as a parameter in calculating the liquefaction potential of an area. The results show that the vulnerability index is related to the sedimentary depth as well as the frequency and amplification factor. Furthermore, the calculated results confirm that the southern area of Bushehr City, which is larger than other areas, has a high liquefaction potential. Furthermore, it is possible to determine the limit of Kg to estimate the liquefaction hazard. Comparing the results confirms that in Bushehr, a soil layer is liquefiable if its related Kg value is over 1.7. This value may change with the conditions of the layer and the soil specification.

References:

 [1] Nakamura, Y., A method for dynamic characteristics estimation of subsurface using microtremor on the ground surface, in Quarterly Report Railway Tech. Res. Inst. 1989. p. 25-30.

[2] Tuladhar, R., et al., Seismic microzonation of the greater Bangkok area using microtremor observations. Earthquake engineering & structural dynamics, 2004. 33(2): p. 211-225.

[3] Walter, T., et al., The 26 May 2006 magnitude 6.4 Yogyakarta earthquake south of Mt. Merapi volcano: Did lahar deposits amplify ground shaking and thus lead to the disaster? Geochemistry, Geophysics, Geosystems, 2008. 9(5).

[4] Seed, H.B. and I.M. Idriss, Simplified procedure for evaluating soil liquefaction potential. Journal of Soil Mechanics & Foundations Div, 1971.

[5] Lermo, J. and F.J. Chávez-García, Site effect evaluation using spectral ratios with only one station. Bulletin of the Seismological Society of America, 1993. 83(5): p. 1574-1594.

[6] Teves-Costa, P., L. Matias, and P. Bard, Seismic behaviour estimation of thin alluvium layers using microtremor recordings. Soil Dynamics and Earthquake Engineering, 1996. 15(3): p. 201-209.

[7] Seed, H.B. and P. De Alba. Use of SPT and CPT tests for evaluating the liquefaction resistance of sands. in Use of in situ tests in geotechnical engineering. 1986. ASCE.

[8] Robertson, P., D. Woeller, and W. Finn, Seismic cone penetration test for evaluating liquefaction potential under cyclic loading. Canadian Geotechnical Journal, 1992. 29(4): p. 686-695.

[9] Harder Jr, L.F., Application of the Becker penetration test for evaluating the liquefaction potential of gravelly soils. 1997.

[10] www.en.wikipedia.org. Bushehr_earthquake. 2013.

[11] Nakamura, Y. Clear identification of fundamental idea of Nakamura’s technique and its applications. in Proceedings of the 12th world conference on earthquake engineering. 2000. Auckland New Zealand.

[12] Nakamura, Y. Clear identification of fundamental idea of Nakamura’s technique and its applications. in Proceedings of the 12th world conference on earthquake engineering. 2000. Auckland New Zealand.

[13] Parolai, S., P. Bormann, and C. Milkereit, New relationships between Vs, thickness of sediments, and resonance frequency calculated by the H/V ratio of seismic noise for the Cologne area (Germany). Bulletin of the seismological society of America, 2002. 92(6): p. 2521-2527.

[14] Chen, Q., et al., Site effects on earthquake ground motion based on microtremor measurements for metropolitan Beijing. Chinese Science Bulletin, 2009. 54(2): p. 280-287.

[15] Mokhberi, M., et al., Experimental evaluation of the H/V spectral ratio capabilities in estimating the subsurface layer characteristics. Iranian Journal of Science and Technology. Transactions of Civil Engineering, 2013. 37(C): p. 457.

[16] Sato, T., Y. Nakamura, and J. Saita. The change of the dynamic characteristics using microtremor. in The 14 th World Conference on Earthquake Engineering. 2008.

[17] Gosar, A., et al., Microtremor study of site effects and soil-structure resonance in the city of Ljubljana (central Slovenia). Bulletin of earthquake engineering, 2010. 8(3): p. 571-592.

[18] Sungkono, D.D.W. and W.U. Triwulan, Evaluation of buildings strength from microtremor analyses. structure, 2011. 6: p. 8.

[19] Huang, H.-C. and Y.-S. Tseng, Characteristics of soil liquefaction using H/V of microtremors in Yuan-Lin area, Taiwan. Terrestrial, Atmospheric and Oceanic Sciences, 2002. 13(3): p. 325-338.

[20] Horike, M., B. Zhao, and H. Kawase, Comparison of site response characteristics inferred from microtremors and earthquake shear waves. Bulletin of the Seismological Society of America, 2001. 91(6): p. 1526-1536.

[21] Nakamura, Y. Seismic vulnerability indices for ground and structures using microtremor. in World Congress on Railway Research in Florence, Italy. 1997.

[22] Mokhberi, M., Vulnerability evaluation of the urban area using the H/V spectral ratio of microtremors. International journal of disaster risk reduction, 2015. 13: p. 369-374.

[23] Andrus, R.D., et al., Comparing liquefaction evaluation methods using penetration-VS relationships. Soil dynamics and earthquake engineering, 2004. 24(9-10): p. 713-721.

[24] Bolton Seed, H., et al., Influence of SPT procedures in soil liquefaction resistance evaluations. Journal of Geotechnical Engineering, 1985. 111(12): p. 1425-1445.

[25] Khalili Noutash, M., R. Dabiri, and M. Hajialilue Bonab, Evaluating the Liquefaction Potential of Soil in the South and Southeast of Tehran based on the Shear Wave Velocity through Empirical Relationships. Journal of Structural Engineering and Geo-Techniques, 2012. 2(1): p. 29-41.

[26] Iwasaki, T. A practical method for assessing soil liquefaction potential based on case studies at various sites in Japan. in Proc. Second Int. Conf. Microzonation Safer Construction Research Application, 1978. 1978.

[27] Baxter, C.D., et al., Correlation between cyclic resistance and shear-wave velocity for providence silts. Journal of geotechnical and geoenvironmental engineering, 2008. 134(1): p. 37-46.

[28] Cetin, K.O., et al., Standard penetration test-based probabilistic and deterministic assessment of seismic soil liquefaction potential. Journal of geotechnical and geoenvironmental engineering, 2004. 130(12): p. 1314-1340.