This paper presents application of microtremor (ambient vibration) and surface wave field techniques for post-earthquake geotechnical reconnaissance purposes in Kathmandu, Nepal. Horizontal-to-vertical spectral ratios (HVSR) are computed from microtremor recordings at 16 individual measurement locations to obtain an estimate of fundamental frequency (site period) of the subsurface soils. A combination of active- and passive-source surface wave array testing was accomplished at five key sites including Kathmandu's Durbar Square and Airport. Joint inversion of each site's higher frequency dispersion and lower frequency HVSR data sets provides an estimate of subsurface material stiffness [i.e., shear wave velocity (VS) depth profiles]. Direct comparison of our VS profiling at Kathmandu Durbar Square and that accomplished by downhole VS and/or standard penetration testing (SPT) profiling yield similar results. Classification of the five sites based on average VS, site period, and/or basin depth is presented. There is little differentiation in these site classification designations amongst the five sites, which does not capture significant differences in observed earthquake damage.
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References
1.
BhandaryN. P., YatabeR., YamamotoK., and PaudyalY. R., 2014. Use of a sparse geo-info database and ambient ground vibration survey in earthquake disaster risk study: A case of Kathmandu Valley, Journal of Civil Engineering Research4, 20–30.
2.
BhattaraiM., AdhikariL. B., GautamU. P., LaurendeauA., LabonneC., Hoste-ColomerR., SèbeO., and HernandezB., 2015. Overview of the large 25 April, 2015, Gorkha, Nepal, earthquake from accelerometric perspectives, Seismological Research Letters86, 1540–1548.
3.
BrownL. T., DiehlJ. G., and NigborR. L., 2000. A simplified procedure to measure average shearwave velocity to a depth of 30 meters (VS30), in Proceedings, 6th International Conference on Seismic Zonation, 12–15 November, 2000, Palm Springs, California.
4.
CordingE. J., 1981. Evaluation of the South-Eastern Slope, Swayambhu Site, Kathmandu Valley, UNESCO Technical Report RP/1979-80/4/3.6/04, Paris, France.
5.
DayS. M., GravesR., BielakJ., DregerD., LarsenS., OlsenK. B., PitarkaA., and Ramirez-GuzmanL., 2008. Model for basin effects on long-period response spectra in southern California, Earthquake Spectra24, 257–277.
6.
ENG1, 1998. Engineering and Environmental Geological Map of Kathmandu Valley, Department of Mines and Geology, Government of Nepal, 1:50,000.
7.
FotiS., HollenderF., GarofaloF., AlbarelloD., AstenM., BardP-Y., CominaC., CornouC., CoxB., Di GiulioG., ForbrigerT., HayashiK., LunedeiE., MartinA., MerceratD., OhrnbergerM., PoggiV., RenalierF., SiciliaD., and SoccoV., 2017. Guidelines for the good practice of surface wave analysis: A product of the InterPACIFIC project, Bulletin of Earthquake Engineering, 1–54, doi:10.1007/s10518-017-0206-7.
8.
GaletzkaJ., MelgarD., GenrichJ. F., GengJ., OwenS., LindseyE. O., XuX., BockY., AvouacJ. P., AdhikariL. B., UpretiB. N., Pratt-SitaulaB., BhattaraiT. N., SitaulaB. P., MooreA., HudnutK. W., SzeligaW., NormandeauJ., FendM., FlouzatM., BollingerL., ShresthaP., KoiralaB., GautamU., BhatteraiM., GuptaR., KandelT., TimsinaC., SapkotaS. N., RajaureS., and MaharjanN., 2015. Slip pulse and resonance of the Kathmandu basin during the 2015 Gorkha earthquake, Nepal, Science349, 1091–1095.
9.
GautamD., 2016. Empirical correlation between uncorrected standard penetration resistance (N) and shear wave velocity (VS) for Kathmandu Valley, Nepal, Geomatics, Natural Hazards and Risk, doi:10.1080/19475705.2016.1243588.
10.
HunterJ. A., and CrowH. L. (eds.), 2012. Shear Wave Velocity Measurement Guidelines for Canadian Seismic Site Characterization in Soil and Rock, Geological Survey of Canada, Open File 7078, doi:10.4095/291753.
11.
Japan International Cooperation Agency (JICA), 2002. The Study on Earthquake Disaster Mitigation in the Kathmandu Valley, Kingdom of Nepal, Japan International Cooperation Agency (JICA) and Ministry of Home Affairs (MoHA), His Majesty's Government of Nepal.
MartinS. S., HoughS. E., and HungC.2015. Ground motions from the 2015 Mw 7.8 Gorka, Nepal, earthquake constrained by a detailed assessment of macroseismic data, Seismological Research Letters86, 1524–1532, doi: 10.1785/0220150138.
14.
MolnarS., and AdhikariS. R., 2015. Seismological aspects and observations of the M7.8 2015 Gorkha earthquake and M7.3 aftershock, in Report on Earthquake Reconnaissance of the M7.8 Gorkha, Nepal Earthquake on April 25, 2015 and its Aftershocks, Canadian Association of Earthquake Engineering, Vancouver, Canada, 17–24.
15.
MolnarS., CassidyJ. F., CastellaroS., CornouC., CrowH., HunterJ. A., MatsushimaS., Sanchez-SesmaF. J., and YongA., 2017a. Application of MHVSR for site characterization: State-of-the-art, Surveys in Geophysics, submitted.
16.
MolnarS., OnwuemekaJ., and AdhikariS., 2017b. Use of ambient vibration methods for post-earthquake geotechnical reconnaissance in Kathmandu, Nepal, Paper 1869, in Proceedings, 16th World Conference on Earthquake Engineering, 9–13 January, 2017, Santiago, Chile.
17.
MolnarS., VenturaC. E., BoroschekR., and ArchilaM., 2015. Site characterization at Chilean strong-motion stations: Comparison of downhole and microtremor shear-wave velocity methods, Soil Dynamics and Earthquake Engineering79, 22–35.
18.
MossR. E. S., ThompsonE. M., KiefferD. S., TiwariB., HashashY. M. A., AcharyaI., Raj AdhikariB., AsimakiD., ClahanK. B., CollinsB. D., DahalS., JibsonR. W., KhadkaD., MacDonaldA., MadugoC. L. M., MasonH. B., PehlivanM., RayamajhiD., and UpretyS., 2015. Geotechnical effects of the 2015 magnitude 7.8 Gorkha, Nepal, earthquake and aftershocks, Seismological Research Letters86, 1514–1523.
19.
National Building Code (NBC), 1994. Nepal National Building Code, Seismic Design of Buildings in Nepal, Government of Nepal, Ministry of Physical Planning and Works, Department of Urban Development and Building Construction, Babar Mahal, Kathmandu, Nepal, 26 pp.
20.
New Zealand Standards (NZS), 2004. NZS 1170.5:2004 Structural Design Actions – Part 5: Earthquake Actions, Standards New Zealand, Ministry of Business, Innovation & Employment, Wellington, New Zealand.
21.
ParkC. B., MillerR. D., and XiaJ., 1999. Multichannel analysis of surface waves, Geophysics64, 800–808.
22.
PaudyalY. R, YatabeR., BhandaryN. P., and DahalR. K., 2013. Basement topography of the Kathmandu Basin using microtremor observation. Journal of Asian Earth Sciences62, 627–637.
23.
PiyaB. K., 2004. Generation of a Geological Database for the Liquefaction Hazard Assessment in Kathmandu Valley, Master's Thesis, International Institute for Geo-Information Science and Earth Observation, Enschede, the Netherlands.
24.
PoovarodomN., ChamlagainD., JirasakjamroonsriA., and WarnitchaiP., 2017. Site characteristics of the Kathmandu Valley from array microtremor observations, Earthquake Spectra33, S85–S93.
25.
RajaureS., AsimakiD., ThompsonE., HoughS. E., MartinS., AmpueroJ. P., DhitalM. R., InbalA., TakaiN., ShigefujiM., BijukchenS., IchiyanagiM., SasataniT., and PaudelL., 2017. Characterizing the Kathmandu Valley sediment response through strong motion recordings of the 2015 Gorkha earthquake sequence, Tectonophysics714–715, 146–157, doi:10.1016/j.tecto.2016.09.030.
26.
Rodriguez-MarekA., BrayJ. D., and AbrahamsonN. A., 2001. An empirical geotechnical seismic site response procedure, Earthquake Spectra17, 65–87.
27.
SakaiH., 2001a. The Kathmandu Basin: An archive of Himalayan uplift and past monsoon climate, Journal of the Nepal Geological Society25 (Special Issue), 1–8.
28.
SakaiH., 2001b. Stratigraphic division and sedimentary facies of the Kathmandu Basin group, central Nepal, Journal of the Nepal Geological Society25 (Special Issue), 19–32.
29.
Tallett-WilliamsS., GoshB., WilkinsonS., FentonC., BurtonP., WhitworthM., DatlaS., FrancoG., TrieuA., DejongM., NovellisV., WhiteT., and LloydT., 2016. Site amplification in the Kathmandu Valley during the 2015 M7.8 Gorkha, Nepal earthquake, Bulletin of Earthquake Engineering14, 3301–3315.
30.
TakaiN., ShigefujiM., RajaureS., BijukchenS., IchiyanagiM., Raj DhitalM., and SasataniT., 2016. Strong ground motion in the Kathmandu Valley during the 2015 Gorkha, Nepal, earthquake, Earth, Planets and Space68, doi:10.1186/s40623-016-0383-7.
31.
WatheletM., 2008. An improved neighborhood algorithm: Parameter conditions and dynamic scaling, Geophysical Research Letters35, doi:10.1029/2008GL033256.
32.
ZhaoJ. X., 2011. Comparison between vS30 and site period as site parameters in ground-motion prediction equations for response spectra, in Proceedings, 4th IASPEI/IAEE International Symposium: Effects of Surface Geology on Seismic Motion, 23–26 August, 2011, University of California, Santa Barbara, CA.
33.
ZhaoJ. X., ZhangJ., AsanoA., OhnoY., OouchiT., TakahashiT., OgawaH., IrikuraK., ThioH. K., SomervilleP. G., FukushimaY., and FukushimaY., 2006. Attenuation relations of strong ground motion in Japan using site classification based on predominant period, Bulletin of the Seismological Society of America96, 898–913.
