Soil profile characterisation of Christchurch Central Business District strong motion stations
This paper presents an overview of the soil profile characteristics at strong motion station (SMS) locations in the Christchurch Central Business District (CBD) based on recently completed geotechnical site investigations. Given the variability of Christchurch soils, detailed investigations were needed in close vicinity to each SMS. In this regard, CPT, SPT and borehole data, and shear wave velocity (Vs) profiles from surface wave dispersion data in close vicinity to the SMSs have been used to develop detailed representative soil profiles at each site and to determine site classes according to the New Zealand standard NZS1170.5. A disparity between the NZS1170.5 site classes based on Vs and SPT N60 investigation techniques is highlighted, and additional studies are needed to harmonize site classification based on these techniques. The short period mode of vibration of soft deposits above gravels, which are found throughout Christchurch, are compared to the long period mode of vibration of the entire soil profile to bedrock. These two distinct modes of vibration require further investigation to determine their impact on the site response. According to current American and European approaches to seismic site classification, all SMSs were classified as problematic soil sites due to the presence of liquefiable strata, soils which are not directly accounted for by the NZS1170.5 approach.
Bradley BA and Cubrinovski C (2011). “Near-source strong ground motions observed in the 22 February 2011 Christchurch earthquake”. Seismological Research Letters, 82(6): 853-865.
Bradley BA (2012). “Strong ground motion characteristics observed in the 4 September 2010 Darfield, New Zealand earthquake”. Soil Dynamics and Earthquake Engineering, 42: 32-46.
Wotherspoon LM, Orense RP, Bradley BA, Cox BR, Wood CM and Green RA (2014). “Geotechnical characterisation of Christchurch strong motion stations”. Earthquake Commission Biennial Grant Report, Project No. 12/629.
Standards New Zealand. (2004). “NZS1170.5: Structural Design Actions-Part 5: Earthquake Actions”. Standards New Zealand, Wellington, NZ.
Building Seismic Safety Council (2003). “NEHRP Recommended Provisions for Seismic Regulations for New Buildings and other Structures, Part1: Provisions”. FEMA 450, Federal Emergency Management Agency, Washington, D.C.
CEN, European Committee for Standardisation (2003). “Eurocode 8: Design Provisions for Earthquake Resistance of Structures, Part 1.1: General rules, seismic actions and rules for buildings”. PrEN1998-1.
GNS Science (2014). GeoNet. http://www.geonet.org.nz. (accessed June 15, 2014).
Brown LJ and Weeber JH (1992). “Geology of the Christchurch urban area”. Institute of Geological and Nuclear Sciences, Lower Hutt.
Brown LJ and Wilson DD (1988). “Stratigraphy of the late Quaternary deposits of the northern Canterbury plains, New Zealand”. New Zealand Journal of Geology and Geophysics, 31: 305-335.
Cousins J and McVerry G (2010). “Overview of strong motion data from the Darfield Earthquake”. Bulletin of the New Zealand Society for Earthquake Engineering, 43(4): 222-227.
Canterbury Earthquake Recovery Authority (CERA) (2012). Geotechnical database for Canterbury earthquake sequence. https://canterburygeotechincaldatabase.projectorbit.com. (accessed June 15, 2014).
Wood CM, Cox BR, Wotherspoon LM and Green RA (2011). “Dynamic site characterization of Christchurch strong motion stations”. Bulletin of the New Zealand Society for Earthquake Engineering, 44(4): 195-204.
Nazarian S and Stokoe II KH (1984). “In situ shear wave velocities from spectral analysis of surface wave tests”. Proc. Eighth World Conference on Earthquake Engineering, San Francisco, California, 31-38.
Stokoe II KH, Wright SG, Bay JA and Roesset JM (1994). “Characterization of geotechnical sites by SASW method”. Proc. 13th International Conference on Soil Mechanics and Foundation Engineering, New Delhi, India, 923-930.
Park CB, Miller RD and Xia J (1999). “Multichannel analysis of surface waves” Geophysics, 64: 800-880.
Tokimatsu K, Shinzawa K, and Kuwayama S (1992). “Use of short-period microtremors for Vs profiling”. Journal of Geotechnical Engineering, 118(10): 1544-1558.
Okada H (2003). “The Microtremor Survey Method”. Geophysical Monograph Series no. 12. Society of Exploration Geophysicists,: 135 pp.
Joh SH (1996). “Advances in interpretation and analysis techniques for spectral-analysis-of-surface-waves (SASW) measurements”. Ph.D. Dissertation, Dept. of Civil, Architectural, and Environmental Engineering, University of Texas, Austin, TX, 240 p.
Nakamura Y (1989). “A Method for Dynamic Characteristics Estimation of Subsurface Using Microtremor on the Ground Surface”. Quarterly Report of the Railway Technical Research Institute, 30(1): 25-33.
Konno K and Ohmachi T (1998). “Ground-motion characteristics estimated from spectral ratio between horizontal and vertical components of microtremor”. Bulletin of the Seismological Society of America, 88(1): 228-241.
Orense RP, Pender MJ and Wotherspoon LM (2011). “Analysis of soil liquefaction during recent Canterbury (New Zealand) earthquakes”. Geotechnical Engineering Journal SEAGS & AGSSEA, 42(3): 8-17.
Robertson PK and Wride CE (1998). “Evaluating cyclic liquefaction potential using the cone penetration test”. Canadian Geotechnical Journal, 35: 442-459.
Lunne T, Robertson PK and Powell JJM (1997). “Cone Penetration Testing in Geotechnical Engineering Practice”. Blackie Academic and Professional, New York.
Wotherspoon LM, Li Z and Haycock I (2015). “Assessment of SPT-CPT correlations using Canterbury site investigation database”. 12th Australia New Zealand Conference on Geomechanics, February 22-25, Wellington, New Zealand
Larkin T and van Houtte C (2014). “Determination of site period for NZS1170.5: 2004”. Bulletin of the New Zealand Society for Earthquake Engineering, 47(1): 28-40.
Standards New Zealand. (2004b). “NZS1170.5: Structural Design Actions-Part 5: Earthquake Actions- Commentary”. Standards New Zealand, Wellington, NZ.
Toshinawa T, Taber JJ and Berrill JB (1997). “Distribution of ground-motion intensity inferred from questionnaire survey, earthquake recordings, and microtremor measurements – A case study in Christchurch, New Zealand, during the 1994 Arthurs Pass earthquake”. Bulletin of the Seismological Society of America, 87(2): 356-369.
Mucciarelli M (2011). “Ambient noise measurements following the 2011 Christchurch earthquake: Relationships with previous microzonation studies, liquefaction, and nonlinearity”. Seismological Research Letters, 82(6): 919-926.
Wotherspoon LM, Orense RP, Bradley BA, Cox BR, Green RA and Wood CM (2014). “Soil profile characterization of Christchurch strong motion stations”. 10th US National Conference on Earthquake Engineering, 21-25 July, Anchorage, Alaska.
Wotherspoon LM, Bradley BA, Thomson EM, Hills AJ, Jeong S, Wood CM and Cox BR (2015). “Development of deep Vs profiles and site periods for the Canterbury region”. NZSEE Annual Technical Conference, April 10-12, Rotorua, New Zealand.
Wotherspoon LM, Orense RP, Green RA, Bradley BA, Cox BR and Wood CM (2013). “Analysis of liquefaction characteristics at Christchurch strong motion stations” in Soil Liquefaction during Recent Large-Scale Earthquakes. CRC Press, Leiden, The Netherlands, 33-44.
Wotherspoon LM, Orense RP, Green RA, Bradley BA, Cox BR and Wood CM (2015). “Assessment of liquefaction evaluation procedures and surficial manifestation severity at Christchurch strong motion stations”. Soil Dynamics and Earthquake Engineering, doi:10.1016/j.soildyn.2015.03.022.
Moss RES, Seed RB, Kayen RE, Stewart JP, Der Kiureghian A, and Cetin KO (2006). “CPT-based probabilistic and deterministic assessment of in situ seismic soil liquefaction potential”. Journal of Geotechnical and Geoenvironmental Engineering, 132(8): 1032-1051.
Idriss IM and Boulanger RW (2008). “Soil liquefaction during earthquakes. Monograph MNO-12”. Earthquake Engineering Research Institute, Oakland, CA, 261 pp.
Nasseri-Moghaddam A, Bennett J and Polan B (2010). “Seismic site class determination using multichannel analysis of surface waves (MASW)”. 9th US National and 10th Canadian Conference on Earthquake Engineering, 25-29 July, Toronto, Canada.
American Association of State Highway and Transportation Officials (2011). "Guide Specifications for LRFD Seismic Bridge Design”. 2nd Edition, Washington, DC.
Copyright (c) 2015 Liam M. Wotherspoon, Rolando P. Orense, Brendon A. Bradley, Brady R. Cox, Clinton M. Wood, Russell A. Green
This work is licensed under a Creative Commons Attribution 4.0 International License.