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Volumn 93, Issue 1-2, 2008, Pages 74-88

Determination of elastic properties of shallow sedimentary deposits applying a spatial autocorrelation method

Author keywords

Geotechnical studies; Seismic microtremor; Shallow sedimentary deposits; Shear wave velocity profile

Indexed keywords

AUTOCORRELATION; BOREHOLE GEOPHYSICS; ELASTIC PROPERTY; LOVE WAVE; MICROTREMOR; RAYLEIGH WAVE; S-WAVE; SEDIMENT PROPERTY; SEISMIC REFRACTION; VELOCITY PROFILE; WAVE VELOCITY;

EID: 35649028995     PISSN: 0169555X     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.geomorph.2006.12.018     Document Type: Article
Times cited : (17)

References (54)
  • 2
    • 0001142955 scopus 로고
    • Space and time spectra of stationary stochastic waves, with special reference to microtremors
    • Aki K. Space and time spectra of stationary stochastic waves, with special reference to microtremors. Bull. Earthq. Res. Inst. Univ. Tokyo 35 (1957) 415-456
    • (1957) Bull. Earthq. Res. Inst. Univ. Tokyo , vol.35 , pp. 415-456
    • Aki, K.1
  • 3
    • 3142640644 scopus 로고    scopus 로고
    • Microtremors Analysis at Teide Volcano (Canary Islands, Spain): assessment of natural frequencies of vibration using time-dependent horizontal-to-vertical spectral ratios
    • Almendros J., Luzón F., and Posadas A. Microtremors Analysis at Teide Volcano (Canary Islands, Spain): assessment of natural frequencies of vibration using time-dependent horizontal-to-vertical spectral ratios. Pure Appl. Geophys. 161 (2004) 1579-1596
    • (2004) Pure Appl. Geophys. , vol.161 , pp. 1579-1596
    • Almendros, J.1    Luzón, F.2    Posadas, A.3
  • 4
    • 0346154958 scopus 로고    scopus 로고
    • Determination of S-wave velocity structure using microtremors and SPAC method applied in Thessaloniki (Greece)
    • Apostolidis P., Raptakis D., Roumelioti Z., and Pitilakis K. Determination of S-wave velocity structure using microtremors and SPAC method applied in Thessaloniki (Greece). Soil Dyn. Earthqu. Eng. 24 (2004) 49-67
    • (2004) Soil Dyn. Earthqu. Eng. , vol.24 , pp. 49-67
    • Apostolidis, P.1    Raptakis, D.2    Roumelioti, Z.3    Pitilakis, K.4
  • 5
    • 0041806569 scopus 로고    scopus 로고
    • Effects of Rayleigh and Love Waves on microtremors H/V spectra
    • Proc. 12th World Conf. on Earthquake Engineering CD-ROM
    • Arai H., and Tokimatsu K. Effects of Rayleigh and Love Waves on microtremors H/V spectra. Proc. 12th World Conf. on Earthquake Engineering. Paper vol. 2232 (2000) CD-ROM
    • (2000) Paper , vol.2232
    • Arai, H.1    Tokimatsu, K.2
  • 6
    • 28144435346 scopus 로고    scopus 로고
    • S-wave velocity profiling by joint inversion of microtremor dispersion curve and horizontal-to-vertical (H/V) spectrum
    • Arai H., and Tokimatsu K. S-wave velocity profiling by joint inversion of microtremor dispersion curve and horizontal-to-vertical (H/V) spectrum. Bull. Seismol. Soc. Am. 95 (2005) 1766-1778
    • (2005) Bull. Seismol. Soc. Am. , vol.95 , pp. 1766-1778
    • Arai, H.1    Tokimatsu, K.2
  • 7
    • 0000166278 scopus 로고    scopus 로고
    • Microtremor measurements: a tool for site effect estimation?
    • Irikura K., Kudo K., Okada H., and Satasini T. (Eds), Balkema, Rotterdam
    • Bard P.Y. Microtremor measurements: a tool for site effect estimation?. In: Irikura K., Kudo K., Okada H., and Satasini T. (Eds). The Effects of Surface Geology on Seismic Motion vol. 3 (1999), Balkema, Rotterdam 1251-1279
    • (1999) The Effects of Surface Geology on Seismic Motion , vol.3 , pp. 1251-1279
    • Bard, P.Y.1
  • 8
    • 79953686470 scopus 로고    scopus 로고
    • Analysis of dense array noise measurements using the modified spatial auto-correlation method (SPAC): application to the Grenoble area
    • Bettig B., Bard P.Y., Scherbaum F., Riepl J., Cotton F., Cornou C., and Hatzfeld D. Analysis of dense array noise measurements using the modified spatial auto-correlation method (SPAC): application to the Grenoble area. Boll. Geofis. Teor. Appl. 42 (2001) 281-304
    • (2001) Boll. Geofis. Teor. Appl. , vol.42 , pp. 281-304
    • Bettig, B.1    Bard, P.Y.2    Scherbaum, F.3    Riepl, J.4    Cotton, F.5    Cornou, C.6    Hatzfeld, D.7
  • 9
    • 0014642808 scopus 로고
    • High-resolution frequency-wavenumber spectrum analysis
    • Capon J. High-resolution frequency-wavenumber spectrum analysis. Proc. I.E.E.E. 57 (1969) 1408-1418
    • (1969) Proc. I.E.E.E. , vol.57 , pp. 1408-1418
    • Capon, J.1
  • 10
    • 35648949657 scopus 로고    scopus 로고
    • Geotechnical report on the Sport Center of the University of Almeria
    • (in Spanish)
    • CEMALSA. Geotechnical report on the Sport Center of the University of Almeria. Survey Number SR2. Geotechnical Report (2004) (in Spanish)
    • (2004) Survey Number SR2. Geotechnical Report
    • CEMALSA1
  • 11
    • 30144435814 scopus 로고    scopus 로고
    • On the correlation of the seismic microtremors
    • 10.1029/2005JB003671
    • Chávez-García F.J., and Luzón F. On the correlation of the seismic microtremors. J. Geophys. Res. 110 (2005) 10.1029/2005JB003671
    • (2005) J. Geophys. Res. , vol.110
    • Chávez-García, F.J.1    Luzón, F.2
  • 12
    • 18144401274 scopus 로고    scopus 로고
    • An alternative approach to the SPAC analysis of microtremors: exploiting stationarity of noise
    • Chávez-García F.J., Rodríguez M., and Stephenson W.R. An alternative approach to the SPAC analysis of microtremors: exploiting stationarity of noise. Bull. Seismol. Soc. Am. 95 (2005) 277-293
    • (2005) Bull. Seismol. Soc. Am. , vol.95 , pp. 277-293
    • Chávez-García, F.J.1    Rodríguez, M.2    Stephenson, W.R.3
  • 13
    • 84988288895 scopus 로고    scopus 로고
    • A new method to determine phase velocities of Rayleigh waves from microseisms
    • Cho I., Tada I., and Shinozaki Y. A new method to determine phase velocities of Rayleigh waves from microseisms. Geophysics 69 (2004) 1535-1551
    • (2004) Geophysics , vol.69 , pp. 1535-1551
    • Cho, I.1    Tada, I.2    Shinozaki, Y.3
  • 14
    • 33645052970 scopus 로고    scopus 로고
    • A generic formulation for microtremor exploration methods using three-components records from a circular array
    • Cho I., Tada T., and Shinozaki Y. A generic formulation for microtremor exploration methods using three-components records from a circular array. Geophys. J. Int. 165 (2006) 236-258
    • (2006) Geophys. J. Int. , vol.165 , pp. 236-258
    • Cho, I.1    Tada, T.2    Shinozaki, Y.3
  • 15
    • 0037824426 scopus 로고    scopus 로고
    • SPAC: an alternative method to estimate earthquake site effects in Mexico City
    • Flores-Estrella H., and Aguirre-González J. SPAC: an alternative method to estimate earthquake site effects in Mexico City. Geofís. Int. 42 (2003) 227-236
    • (2003) Geofís. Int. , vol.42 , pp. 227-236
    • Flores-Estrella, H.1    Aguirre-González, J.2
  • 16
    • 33745444715 scopus 로고    scopus 로고
    • Characterization of the sedimentary cover of the Zafarraya basin (Southern Spain) by means of ambient noise
    • García-Jerez A., Luzón F., Navarro M., and Pérez-Ruiz J.A. Characterization of the sedimentary cover of the Zafarraya basin (Southern Spain) by means of ambient noise. Bull. Seismol. Soc. Am. 96 (2006) 957-967
    • (2006) Bull. Seismol. Soc. Am. , vol.96 , pp. 957-967
    • García-Jerez, A.1    Luzón, F.2    Navarro, M.3    Pérez-Ruiz, J.A.4
  • 17
    • 84865844592 scopus 로고    scopus 로고
    • Computation of dispersion curves for Rayleigh and Love waves using horizontal components of seismic microtremor
    • Eighth U.S. National Conference on Earthquake Engineering, San Francisco
    • García-Jerez A., Luzón F., and Navarro M. Computation of dispersion curves for Rayleigh and Love waves using horizontal components of seismic microtremor. Eighth U.S. National Conference on Earthquake Engineering, San Francisco. Paper vol. 1377 (2006)
    • (2006) Paper , vol.1377
    • García-Jerez, A.1    Luzón, F.2    Navarro, M.3
  • 18
    • 0002392976 scopus 로고
    • The dispersion of surface waves on multilayered media
    • Haskell N.A. The dispersion of surface waves on multilayered media. Bull. Seismol. Soc. Am. 43 (1953) 17-34
    • (1953) Bull. Seismol. Soc. Am. , vol.43 , pp. 17-34
    • Haskell, N.A.1
  • 19
    • 0018434339 scopus 로고
    • A signal processing method for circular arrays
    • Henstridge D.J. A signal processing method for circular arrays. Geophysics 44 (1979) 179-184
    • (1979) Geophysics , vol.44 , pp. 179-184
    • Henstridge, D.J.1
  • 21
    • 0347776242 scopus 로고    scopus 로고
    • Microtremor measurements used to map thickness of soft sediments
    • Ibs von Seht M., and Wohlenberg J. Microtremor measurements used to map thickness of soft sediments. Bull. Seismol. Soc. Am. 89 (1999) 250-259
    • (1999) Bull. Seismol. Soc. Am. , vol.89 , pp. 250-259
    • Ibs von Seht, M.1    Wohlenberg, J.2
  • 23
    • 13344294353 scopus 로고    scopus 로고
    • Array measurements of S-wave velocities from ambient vibrations
    • Kind F., Fäh D., and Giardini D. Array measurements of S-wave velocities from ambient vibrations. Geophys. J. Int. 160 (2005) 114-126
    • (2005) Geophys. J. Int. , vol.160 , pp. 114-126
    • Kind, F.1    Fäh, D.2    Giardini, D.3
  • 24
    • 0031714911 scopus 로고    scopus 로고
    • Ground-motion characteristics estimated from spectral ratio between horizontal and vertical components of microtremor
    • Konno K., and Ohmachi T. Ground-motion characteristics estimated from spectral ratio between horizontal and vertical components of microtremor. Bull. Seismol. Soc. Am. 88 (1998) 228-241
    • (1998) Bull. Seismol. Soc. Am. , vol.88 , pp. 228-241
    • Konno, K.1    Ohmachi, T.2
  • 25
    • 0029476344 scopus 로고
    • Simulation of the seismic response of a 2D sedimentary basin: a comparison between the indirect boundary element method and a hybrid technique
    • Luzón F., Aoi S., Fäh D., and Sánchez-Sesma F.J. Simulation of the seismic response of a 2D sedimentary basin: a comparison between the indirect boundary element method and a hybrid technique. Bull. Seismol. Soc. Am. 85 (1995) 1501-1506
    • (1995) Bull. Seismol. Soc. Am. , vol.85 , pp. 1501-1506
    • Luzón, F.1    Aoi, S.2    Fäh, D.3    Sánchez-Sesma, F.J.4
  • 26
    • 1642488194 scopus 로고    scopus 로고
    • Three-dimensional simulation of ground motion in the Zafarraya basin (Southern Spain) up to 1.335 Hz under incident plane waves
    • Luzón F., Gil-Zepeda S.A., Sánchez-Sesma F.J., and Ortiz-Alemán C. Three-dimensional simulation of ground motion in the Zafarraya basin (Southern Spain) up to 1.335 Hz under incident plane waves. Geophys. J. Int. 156 (2004) 584-594
    • (2004) Geophys. J. Int. , vol.156 , pp. 584-594
    • Luzón, F.1    Gil-Zepeda, S.A.2    Sánchez-Sesma, F.J.3    Ortiz-Alemán, C.4
  • 27
    • 33744781013 scopus 로고    scopus 로고
    • A method to estimate phase velocities of surface waves using array observations records of three-component microtremors
    • Morikawa H. A method to estimate phase velocities of surface waves using array observations records of three-component microtremors. Struct. Eng./ Earthqu. Eng. JSCE 23 (2006) 143s-148s
    • (2006) Struct. Eng./ Earthqu. Eng. JSCE , vol.23
    • Morikawa, H.1
  • 28
    • 4243096215 scopus 로고    scopus 로고
    • A method to estimate phase velocities of Rayleigh waves using microseism simultaneously observed at two sites
    • Morikawa H., Sawada S., and Akamatsu J. A method to estimate phase velocities of Rayleigh waves using microseism simultaneously observed at two sites. Bull. Seismol. Soc. Am. 94 (2004) 961-976
    • (2004) Bull. Seismol. Soc. Am. , vol.94 , pp. 961-976
    • Morikawa, H.1    Sawada, S.2    Akamatsu, J.3
  • 29
    • 0024480933 scopus 로고
    • A method for dynamic characteristics estimation of subsurface using microtremors on the ground surface
    • Nakamura Y. A method for dynamic characteristics estimation of subsurface using microtremors on the ground surface. Q. Rep. RTRI 30 (1989) 25-33
    • (1989) Q. Rep. RTRI , vol.30 , pp. 25-33
    • Nakamura, Y.1
  • 31
    • 35649025075 scopus 로고    scopus 로고
    • Nazarian, S., 1984. In situ determination of elastic moduli of soil deposits and pavement systems by spectral analysis of surface waves method. Ph.D. dissertation, Univ. of Texas, Austin.
  • 32
    • 0000238336 scopus 로고
    • A simplex method for function minimization
    • Nelder J.A., and Mead R. A simplex method for function minimization. Comput. J. 7 (1965) 308-313
    • (1965) Comput. J. , vol.7 , pp. 308-313
    • Nelder, J.A.1    Mead, R.2
  • 33
    • 35648997688 scopus 로고    scopus 로고
    • Determination of subsurface structure of Tottori plain using microtremors and gravity anomaly
    • Noguchi T., and Nishida R. Determination of subsurface structure of Tottori plain using microtremors and gravity anomaly. J. Nat. Disaster Sci. 24 (2002) 1-13
    • (2002) J. Nat. Disaster Sci. , vol.24 , pp. 1-13
    • Noguchi, T.1    Nishida, R.2
  • 34
    • 0036704521 scopus 로고    scopus 로고
    • A comparison of ESAC and FK methods of estimating phase velocity using arbitrarily shaped microtremor arrays
    • Ohori M., Nobata A., and Wakamatsu K. A comparison of ESAC and FK methods of estimating phase velocity using arbitrarily shaped microtremor arrays. Bull. Seismol. Soc. Am. 92 (2002) 2323-2332
    • (2002) Bull. Seismol. Soc. Am. , vol.92 , pp. 2323-2332
    • Ohori, M.1    Nobata, A.2    Wakamatsu, K.3
  • 35
    • 0017946399 scopus 로고
    • Empirical shear wave velocity equations in terms of characteristic soil indexes
    • Ohta Y., and Goto N. Empirical shear wave velocity equations in terms of characteristic soil indexes. Earthq. Eng. Struct. Dyn. 6 (1978) 167-187
    • (1978) Earthq. Eng. Struct. Dyn. , vol.6 , pp. 167-187
    • Ohta, Y.1    Goto, N.2
  • 36
    • 33750372276 scopus 로고    scopus 로고
    • Frequency wavenumber and spatial autocorrelation methods for dispersion curve determination from ambient vibration recordings
    • XIII World conference on Earthquake Engineering, Vancouver, B.C., Canada
    • Ohrnberger M., Schissele E., Cornou C., Bonnefoy-Claudet S., Wathelet M., Savvaidis A., Scherbaum F., and Jongmans D. Frequency wavenumber and spatial autocorrelation methods for dispersion curve determination from ambient vibration recordings. XIII World conference on Earthquake Engineering, Vancouver, B.C., Canada. Paper vol. 0946 (2004)
    • (2004) Paper , vol.946
    • Ohrnberger, M.1    Schissele, E.2    Cornou, C.3    Bonnefoy-Claudet, S.4    Wathelet, M.5    Savvaidis, A.6    Scherbaum, F.7    Jongmans, D.8
  • 37
    • 33744784369 scopus 로고
    • An exploration method using microtremors (1) - an analytical background to discriminate Love wave in microtremors
    • (in Japanese)
    • Okada H., and Matsushima T. An exploration method using microtremors (1) - an analytical background to discriminate Love wave in microtremors. Proc. 81st Annual Meeting for Society of Exploration Geophysicist of Japan (1989) 15-19 (in Japanese)
    • (1989) Proc. 81st Annual Meeting for Society of Exploration Geophysicist of Japan , pp. 15-19
    • Okada, H.1    Matsushima, T.2
  • 38
    • 0033133621 scopus 로고    scopus 로고
    • Multichannel analysis of surface waves
    • Park C.B., Miller R.D., and Xia J. Multichannel analysis of surface waves. Geophysics 64 (1999) 800-808
    • (1999) Geophysics , vol.64 , pp. 800-808
    • Park, C.B.1    Miller, R.D.2    Xia, J.3
  • 39
    • 31444455204 scopus 로고    scopus 로고
    • S-wave velocity profiles for earthquake engineering purposes for the Cologne Area (Germany)
    • Parolai S., Richwalski S.M., Milkereit C., and Fäh D. S-wave velocity profiles for earthquake engineering purposes for the Cologne Area (Germany). Bull. Earthq. Eng. 4 (2006) 65-94
    • (2006) Bull. Earthq. Eng. , vol.4 , pp. 65-94
    • Parolai, S.1    Richwalski, S.M.2    Milkereit, C.3    Fäh, D.4
  • 40
    • 3042727937 scopus 로고    scopus 로고
    • Pumping seawater from coastal aquifers for supplying desalination plants
    • Pulido-Bosch A., Pulido-Leboeuf P., and Gisbert J. Pumping seawater from coastal aquifers for supplying desalination plants. Geol. Acta 2 (2004) 97-107
    • (2004) Geol. Acta , vol.2 , pp. 97-107
    • Pulido-Bosch, A.1    Pulido-Leboeuf, P.2    Gisbert, J.3
  • 41
    • 85009348042 scopus 로고    scopus 로고
    • Resolving a velocity inversion al the geotechnical scale using the microtremor (passive seismic) survey method
    • Roberts J.C., and Asten M.W. Resolving a velocity inversion al the geotechnical scale using the microtremor (passive seismic) survey method. Explor. Geophys. 35 (2004) 14-18
    • (2004) Explor. Geophys. , vol.35 , pp. 14-18
    • Roberts, J.C.1    Asten, M.W.2
  • 42
    • 0032753561 scopus 로고    scopus 로고
    • Geophysical inversion with a neighbourhood algorithm: I. Searching a parameter space
    • Sambridge M. Geophysical inversion with a neighbourhood algorithm: I. Searching a parameter space. Geophys. J. Int. 138 (1999) 479-494
    • (1999) Geophys. J. Int. , vol.138 , pp. 479-494
    • Sambridge, M.1
  • 43
    • 0032695503 scopus 로고    scopus 로고
    • Geophysical inversion with a neighbourhood algorithm: II. Appraising the ensemble
    • Sambridge M. Geophysical inversion with a neighbourhood algorithm: II. Appraising the ensemble. Geophys. J. Int. 138 (1999) 727-746
    • (1999) Geophys. J. Int. , vol.138 , pp. 727-746
    • Sambridge, M.1
  • 44
    • 33845600704 scopus 로고    scopus 로고
    • Elastodynamic 2D Green function retrieval from cross-correlation: canonical inclusion problem
    • 10.1029/2006GL026454
    • Sánchez-Sesma F.J., Pérez-Ruiz J.A., Campillo M., and Luzón F. Elastodynamic 2D Green function retrieval from cross-correlation: canonical inclusion problem. Geophys. Res. Lett. 33 (2006) L13305 10.1029/2006GL026454
    • (2006) Geophys. Res. Lett. , vol.33
    • Sánchez-Sesma, F.J.1    Pérez-Ruiz, J.A.2    Campillo, M.3    Luzón, F.4
  • 45
    • 0037342923 scopus 로고    scopus 로고
    • Determination of shallow shear wave velocity profiles in the Cologne, Germany area using ambient vibrations
    • Scherbaum F., Hinzen K.G., and Ohrnberger M. Determination of shallow shear wave velocity profiles in the Cologne, Germany area using ambient vibrations. Geophys. J. Int. 152 (2003) 597-612
    • (2003) Geophys. J. Int. , vol.152 , pp. 597-612
    • Scherbaum, F.1    Hinzen, K.G.2    Ohrnberger, M.3
  • 47
    • 1842829978 scopus 로고    scopus 로고
    • Comparison of body and rayleigh wave displacements generated by a vertical force on a layered elastic medium
    • Proc. 11th World Conference on Earthquake Engineering CD-ROM
    • Tamura S. Comparison of body and rayleigh wave displacements generated by a vertical force on a layered elastic medium. Proc. 11th World Conference on Earthquake Engineering. Paper vol. 1722 (1996) CD-ROM
    • (1996) Paper , vol.1722
    • Tamura, S.1
  • 48
    • 0019999145 scopus 로고
    • Generalized nonlinear inverse problems solved using the least-squares criterion
    • Tarantola A., and Valette B. Generalized nonlinear inverse problems solved using the least-squares criterion. Rev. Geophys. Space Phys. 20 (1982) 219-232
    • (1982) Rev. Geophys. Space Phys. , vol.20 , pp. 219-232
    • Tarantola, A.1    Valette, B.2
  • 49
    • 0000602822 scopus 로고    scopus 로고
    • Geotechnical site characterization using surface waves
    • Ishihara K. (Ed), Balkema, Rótterdam
    • Tokimatsu K. Geotechnical site characterization using surface waves. In: Ishihara K. (Ed). Earthquake Geotechnical Engineering (1997), Balkema, Rótterdam 1333-1368
    • (1997) Earthquake Geotechnical Engineering , pp. 1333-1368
    • Tokimatsu, K.1
  • 50
    • 0026941973 scopus 로고
    • Effects of multiple modes on Rayleigh wave dispersion characteristics
    • Tokimatsu K., Tamura S., and Kojima H. Effects of multiple modes on Rayleigh wave dispersion characteristics. J. Geotech. Eng. ASCE 118 (1992) 1529-1543
    • (1992) J. Geotech. Eng. ASCE , vol.118 , pp. 1529-1543
    • Tokimatsu, K.1    Tamura, S.2    Kojima, H.3
  • 51
    • 35649024479 scopus 로고    scopus 로고
    • Wathelet, M., 2005. Array recordings of ambient vibrations: surface-wave inversion. PhD thesis, University of Liège, Belgium.
  • 52
    • 0028197806 scopus 로고
    • Seismic refraction testing - a tutorial
    • Woods R.C. (Ed), Balkema, Rótterdam
    • Whiteley R.J. Seismic refraction testing - a tutorial. In: Woods R.C. (Ed). Geophysical Characterisation of Sites (1994), Balkema, Rótterdam 45-47
    • (1994) Geophysical Characterisation of Sites , pp. 45-47
    • Whiteley, R.J.1
  • 53
    • 21644435310 scopus 로고    scopus 로고
    • Comparison of performance of heuristic search methods for phase velocity inversion in shallow surface wave method
    • Yamanaka H. Comparison of performance of heuristic search methods for phase velocity inversion in shallow surface wave method. J. Environ. Eng. Geophys. 10 (2005) 163-173
    • (2005) J. Environ. Eng. Geophys. , vol.10 , pp. 163-173
    • Yamanaka, H.1
  • 54
    • 0030454299 scopus 로고    scopus 로고
    • Application of generic algorithms to an inversion of surface-wave dispersion data
    • Yamanaka H., and Ishida H. Application of generic algorithms to an inversion of surface-wave dispersion data. Bull. Seismol. Soc. Am. 86 (1996) 436-444
    • (1996) Bull. Seismol. Soc. Am. , vol.86 , pp. 436-444
    • Yamanaka, H.1    Ishida, H.2


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