메뉴 건너뛰기




Volumn 9, Issue 3, 2011, Pages 841-868

Site effects "on the rock": The case of Castelvecchio Subequo (L'Aquila, central Italy)

Author keywords

2009 L'Aquila earthquake; Ambient seismic noise; Central Italy; Geomechanical analysis; Jointing conditions; Rock sites; Site effects; Spectral ratios; Structural characteristics

Indexed keywords

2009 L'AQUILA EARTHQUAKE; AMBIENT SEISMIC NOISE; CENTRAL ITALY; GEOMECHANICAL ANALYSIS; JOINTING CONDITIONS; SITE EFFECTS; SPECTRAL RATIOS; STRUCTURAL CHARACTERISTICS;

EID: 79955835067     PISSN: 1570761X     EISSN: 15731456     Source Type: Journal    
DOI: 10.1007/s10518-011-9263-5     Document Type: Article
Times cited : (60)

References (63)
  • 2
    • 0033081671 scopus 로고    scopus 로고
    • Effects of surface topography on seismic ground response in Egion (Greece) 15 June 1995 earthquake
    • Athanasopoulos GA, Pelekis PC, Leonidou EA (1999) Effects of surface topography on seismic ground response in Egion (Greece) 15 June 1995 earthquake. Soil Dyn Earthq Eng 18: 135-149.
    • (1999) Soil Dyn Earthq Eng , vol.18 , pp. 135-149
    • Athanasopoulos, G.A.1    Pelekis, P.C.2    Leonidou, E.A.3
  • 5
    • 0020389281 scopus 로고
    • Diffracted waves and displacement fields over twodimensional elevated topographies
    • Bard PY (1982) Diffracted waves and displacement fields over twodimensional elevated topographies. Geophys J Int 71: 731-760.
    • (1982) Geophys J Int , vol.71 , pp. 731-760
    • Bard, P.Y.1
  • 6
    • 0001497124 scopus 로고
    • Underground and ridge site effects: comparison of observation and theory
    • Bard PY, Tucker BE (1985) Underground and ridge site effects: comparison of observation and theory. Bull Seismol Soc Am 75: 905-922.
    • (1985) Bull Seismol Soc Am , vol.75 , pp. 905-922
    • Bard, P.Y.1    Tucker, B.E.2
  • 7
    • 3242763782 scopus 로고    scopus 로고
    • The 1997-1998 Umbria-Marche sequence (central Italy): source, path and site effects estimated from strong motion data recorded in the epicentral area
    • doi:10.1029/2003JB002857
    • Bindi D, Castro R, Franceschina G, Luzi L, Pacor F (2004) The 1997-1998 Umbria-Marche sequence (central Italy): source, path and site effects estimated from strong motion data recorded in the epicentral area. J Geophys Res 109: B04312. doi: 10. 1029/2003JB002857.
    • (2004) J Geophys Res , vol.109
    • Bindi, D.1    Castro, R.2    Franceschina, G.3    Luzi, L.4    Pacor, F.5
  • 8
    • 70450199413 scopus 로고    scopus 로고
    • The Mw 6.3, 2009 L'Aquila earthquake: source, path and site effects from spectral analysis of strong motion data
    • Bindi D, Pacor F, Luzi L, Massa M, Ameri G (2009) The Mw 6. 3, 2009 L'Aquila earthquake: source, path and site effects from spectral analysis of strong motion data. Geophys J Int 179: 1573-1579.
    • (2009) Geophys J Int , vol.179 , pp. 1573-1579
    • Bindi, D.1    Pacor, F.2    Luzi, L.3    Massa, M.4    Ameri, G.5
  • 9
    • 4344690650 scopus 로고    scopus 로고
    • Defining a model of 3D seismogenic sources for Seismic Hazard Assessment applications: the case of central Apennines (Italy)
    • Boncio P, Lavecchia G, Pace B (2004) Defining a model of 3D seismogenic sources for Seismic Hazard Assessment applications: the case of central Apennines (Italy). J Seismol 8: 407-425.
    • (2004) J Seismol , vol.8 , pp. 407-425
    • Boncio, P.1    Lavecchia, G.2    Pace, B.3
  • 11
    • 0000876729 scopus 로고
    • A note on the effect of simple topography on seismic SH waves
    • Boore DM (1972) A note on the effect of simple topography on seismic SH waves. Bull Seismol Soc Am 62: 275-284.
    • (1972) Bull Seismol Soc Am , vol.62 , pp. 275-284
    • Boore, D.M.1
  • 12
    • 0001739527 scopus 로고
    • Stochastic simulation of high-frequency ground motion based on seismological models of the radiated spectra
    • Boore DM (1983) Stochastic simulation of high-frequency ground motion based on seismological models of the radiated spectra. Bull Seism Soc Am 73: 1865-1894.
    • (1983) Bull Seism Soc Am , vol.73 , pp. 1865-1894
    • Boore, D.M.1
  • 13
    • 0037343925 scopus 로고    scopus 로고
    • Simulation of ground motion using the stochastic method
    • Boore DM (2003) Simulation of ground motion using the stochastic method. Pure Appl Geophys 160: 635-676.
    • (2003) Pure Appl Geophys , vol.160 , pp. 635-676
    • Boore, D.M.1
  • 14
    • 0014742110 scopus 로고
    • Effects of local geology on ground motion near San Francisco Bay
    • Borcherdt RD (1970) Effects of local geology on ground motion near San Francisco Bay. Bull Seismol Soc Am 60: 29-61.
    • (1970) Bull Seismol Soc Am , vol.60 , pp. 29-61
    • Borcherdt, R.D.1
  • 15
    • 0013335102 scopus 로고
    • La geologia della media valle dell'Aterno
    • Bosi C, Bertini T (1970) La geologia della media valle dell'Aterno. Mem Soc Geol It 9: 719-777.
    • (1970) Mem Soc Geol It , vol.9 , pp. 719-777
    • Bosi, C.1    Bertini, T.2
  • 16
    • 0030479673 scopus 로고    scopus 로고
    • Seismic response of a hill: the example of Tarzana
    • Bouchon M, Barker JS (1996) Seismic response of a hill: the example of Tarzana. Calif Bull Seismol Soc Am 86: 66-72.
    • (1996) Calif Bull Seismol Soc Am , vol.86 , pp. 66-72
    • Bouchon, M.1    Barker, J.S.2
  • 18
    • 84879880340 scopus 로고    scopus 로고
    • Extensional basins in the tectonically bimodal central Apennines fold-thrust belt, Italy: response to corner flow above a subducting slab in retrograde motion
    • Cavinato GP, De Celles PG (1999) Extensional basins in the tectonically bimodal central Apennines fold-thrust belt, Italy: response to corner flow above a subducting slab in retrograde motion. Geology 27: 955-958.
    • (1999) Geology , vol.27 , pp. 955-958
    • Cavinato, G.P.1    de Celles, P.G.2
  • 19
    • 0001292677 scopus 로고
    • Topographical and geological amplifications determined from strong motion and aftershock records of the 3 March 1985 Chile earthquake
    • Çelebi M (1987) Topographical and geological amplifications determined from strong motion and aftershock records of the 3 March 1985 Chile earthquake. Bull Seismol Soc Am 77: 1147-1167.
    • (1987) Bull Seismol Soc Am , vol.77 , pp. 1147-1167
    • Çelebi, M.1
  • 20
    • 0030441582 scopus 로고    scopus 로고
    • Topographic site effects and HVSR. A comparison between observation and theory
    • Chávez-García F, Sánchez LR, Hatzfeld D (1996) Topographic site effects and HVSR. A comparison between observation and theory. Bull Seismol Soc Am 86: 1559-1573.
    • (1996) Bull Seismol Soc Am , vol.86 , pp. 1559-1573
    • Chávez-García, F.1    Sánchez, L.R.2    Hatzfeld, D.3
  • 21
    • 49349088150 scopus 로고    scopus 로고
    • New GPS constraints on the kinematics of the Apennines subduction
    • Devoti R, Riguzzi F, Cuffaro M, Doglioni C (2008) New GPS constraints on the kinematics of the Apennines subduction. Earth Planet Sci Lett 273: 163-174.
    • (2008) Earth Planet Sci Lett , vol.273 , pp. 163-174
    • Devoti, R.1    Riguzzi, F.2    Cuffaro, M.3    Doglioni, C.4
  • 22
    • 73649091446 scopus 로고    scopus 로고
    • Evidence for surface rupture associated with the Mw 6.3 L'Aquila earthquake sequence of April 2009 (central Italy)
    • Emergeo Working Group
    • Emergeo Working Group: (2010) Evidence for surface rupture associated with the Mw 6. 3 L'Aquila earthquake sequence of April 2009 (central Italy). Terra Nova 22: 43-51.
    • (2010) Terra Nova , vol.22 , pp. 43-51
  • 24
    • 78751582885 scopus 로고    scopus 로고
    • Evidenze di fagliazione normale tardo-olocenica nel settore compreso fra la conca Subequana e la Media Valle dell'Aterno, a sud dell'area epicentrale del terremoto di L'Aquila del 6 Aprile 2009
    • GNGTS 28° Convegno Nazionale, 16-19 Nov., Trieste (Italy)
    • Falcucci E, Gori S, Moro M, Galadini F, Marzorati S, Ladina C, Piccarreda D, Fredi P (2009) Evidenze di fagliazione normale tardo-olocenica nel settore compreso fra la conca Subequana e la Media Valle dell'Aterno, a sud dell'area epicentrale del terremoto di L'Aquila del 6 Aprile 2009. Implicazioni sismotettoniche. GNGTS 28° Convegno Nazionale, 16-19 Nov., Trieste (Italy).
    • (2009) Implicazioni sismotettoniche
    • Falcucci, E.1    Gori, S.2    Moro, M.3    Galadini, F.4    Marzorati, S.5    Ladina, C.6    Piccarreda, D.7    Fredi, P.8
  • 25
    • 79955088129 scopus 로고    scopus 로고
    • The 2009 L'Aquila earthquake (Italy): what next in the region? Hints from stress diffusion analysis and normal fault activity
    • doi:10.1016/j.epsl.2011.03.016
    • Falcucci E, Gori S, Moro M, Pisani AR, Melini D, Galadini F, Fredi P (2011) The 2009 L'Aquila earthquake (Italy): what next in the region? Hints from stress diffusion analysis and normal fault activity. Earth Planet Sci Lett. doi: 10. 1016/j. epsl. 2011. 03. 016.
    • (2011) Earth Planet Sci Lett
    • Falcucci, E.1    Gori, S.2    Moro, M.3    Pisani, A.R.4    Melini, D.5    Galadini, F.6    Fredi, P.7
  • 27
    • 73649142907 scopus 로고    scopus 로고
    • Foglio CARG 1: 50, 000, Foglio N. 369, Sulmona
    • Foglio CARG 1: 50, 000 (2009) Cartografia Geologica Ufficiale. Foglio N. 369, Sulmona.
    • (2009) Cartografia Geologica Ufficiale
  • 28
    • 0033759994 scopus 로고    scopus 로고
    • Active tectonics in the central Apennines (Italy)-input data for seismic hazard assessment
    • Galadini F, Galli P (2000) Active tectonics in the central Apennines (Italy)-input data for seismic hazard assessment. Nat Hazards 22: 225-270.
    • (2000) Nat Hazards , vol.22 , pp. 225-270
    • Galadini, F.1    Galli, P.2
  • 32
    • 0023822844 scopus 로고
    • The effect of topography on earthquake ground motion: a review and new results
    • Géli L, Bard PY (1988) The effect of topography on earthquake ground motion: a review and new results. Bull Seismol Soc Am 78: 42-63.
    • (1988) Bull Seismol Soc Am , vol.78 , pp. 42-63
    • Géli, L.1    Bard, P.Y.2
  • 33
    • 56949088010 scopus 로고    scopus 로고
    • Low-velocity zone and topography as a source of site amplification effect on Tarzana Hill, California
    • Graizer V (2009) Low-velocity zone and topography as a source of site amplification effect on Tarzana Hill, California. Soil Dyn Earthq Eng 29: 324-332.
    • (2009) Soil Dyn Earthq Eng , vol.29 , pp. 324-332
    • Graizer, V.1
  • 34
    • 0000613899 scopus 로고
    • The effect of Appalachian Mountain topography on seismic waves
    • Griffiths DW, Bollinger GA (1979) The effect of Appalachian Mountain topography on seismic waves. Bull Seismol Soc Am 69: 1081-1105.
    • (1979) Bull Seismol Soc Am , vol.69 , pp. 1081-1105
    • Griffiths, D.W.1    Bollinger, G.A.2
  • 36
    • 0004159503 scopus 로고
    • 3rd edn. Institution of Mining and Metallurgy, London
    • Hoek E, Bray JW (1981) Rock slope engineering, 3rd edn. Institution of Mining and Metallurgy, London.
    • (1981) Rock slope engineering
    • Hoek, E.1    Bray, J.W.2
  • 37
    • 0025664568 scopus 로고
    • Topography effect at the critical SV-wave incidence: possible explanation of damage pattern by the Whittier Narrows, California, earthquake of 1 October 1987
    • Kawase H, Aki K (1990) Topography effect at the critical SV-wave incidence: possible explanation of damage pattern by the Whittier Narrows, California, earthquake of 1 October 1987. Bull Seismol Soc Am 80: 1-22.
    • (1990) Bull Seismol Soc Am , vol.80 , pp. 1-22
    • Kawase, H.1    Aki, K.2
  • 38
    • 0031815577 scopus 로고    scopus 로고
    • The spectral element method: an efficient tool to simulate the seismic response of 2D and 3D geological structures
    • Komatitsch D, Vilotte JP (1998) The spectral element method: an efficient tool to simulate the seismic response of 2D and 3D geological structures. Bull Seismol Soc Am 88: 368-392.
    • (1998) Bull Seismol Soc Am , vol.88 , pp. 368-392
    • Komatitsch, D.1    Vilotte, J.P.2
  • 39
    • 0031714911 scopus 로고    scopus 로고
    • Ground-motion characteristics estimated from spectral ratio between horizontal and vertical components of microtremors
    • Konno K, Ohmachi T (1998) Ground-motion characteristics estimated from spectral ratio between horizontal and vertical components of microtremors. Bull Seism Soc Am 88: 228-241.
    • (1998) Bull Seism Soc Am , vol.88 , pp. 228-241
    • Konno, K.1    Ohmachi, T.2
  • 40
    • 0009062496 scopus 로고    scopus 로고
    • Experimental study of the ground motion on a large scale topographic hill at Kitherion (Greece)
    • Le Brun B, Hatzfeld D, Bard PY, Bouchon M (1999) Experimental study of the ground motion on a large scale topographic hill at Kitherion (Greece). J Seismol 3: 1-15.
    • (1999) J Seismol , vol.3 , pp. 1-15
    • Le Brun, B.1    Hatzfeld, D.2    Bard, P.Y.3    Bouchon, M.4
  • 41
    • 0028574502 scopus 로고
    • Are microtremors useful in site response evaluation?
    • Lermo J, Chavez-Garcia FJ (1993) Are microtremors useful in site response evaluation?. Bull Seismol Soc Am 84: 1350-1364.
    • (1993) Bull Seismol Soc Am , vol.84 , pp. 1350-1364
    • Lermo, J.1    Chavez-Garcia, F.J.2
  • 42
    • 0032222068 scopus 로고    scopus 로고
    • 0 from response spectra of large earthquakes in Greece
    • 0 from response spectra of large earthquakes in Greece. Bull Seismol Soc Am 88: 170-182.
    • (1998) Bull Seismol Soc Am , vol.88 , pp. 170-182
    • Margaris, B.N.1    Boore, D.M.2
  • 43
    • 33750454746 scopus 로고    scopus 로고
    • Seismic microzonation of jointed rock-mass ridges through a combined geomechanical and seismometric approach
    • Martino S, Minutolo A, Paciello A, Rovelli A, Scarascia Mugnozza G, Verrubbi V (2006) Seismic microzonation of jointed rock-mass ridges through a combined geomechanical and seismometric approach. Nat Hazards 39: 419-449.
    • (2006) Nat Hazards , vol.39 , pp. 419-449
    • Martino, S.1    Minutolo, A.2    Paciello, A.3    Rovelli, A.4    Scarascia Mugnozza, G.5    Verrubbi, V.6
  • 44
    • 78650148970 scopus 로고    scopus 로고
    • Experimental approach for estimating seismic amplification effects at the top of a ridge and their implication on ground motion predictions: the case of Narni (Central Italy)
    • Massa M, Lovati S, D'Alema E, Ferretti G, Bakavoli M (2010) Experimental approach for estimating seismic amplification effects at the top of a ridge and their implication on ground motion predictions: the case of Narni (Central Italy). Bull Seismol Soc Am 100: 3020-3034.
    • (2010) Bull Seismol Soc Am , vol.100 , pp. 3020-3034
    • Massa, M.1    Lovati, S.2    D'Alema, E.3    Ferretti, G.4    Bakavoli, M.5
  • 45
    • 7244254470 scopus 로고    scopus 로고
    • Ambient noise levels in the continental United States
    • McNamara DE, Buland RP (2004) Ambient noise levels in the continental United States. Bull Seismol Soc Am 94(4): 1517-1527.
    • (2004) Bull Seismol Soc Am , vol.94 , Issue.4 , pp. 1517-1527
    • McNamara, D.E.1    Buland, R.P.2
  • 47
    • 0024480933 scopus 로고
    • A method for dynamic characteristics estimations of subsurface using microtremors on the ground surface
    • Nakamura Y (1989) A method for dynamic characteristics estimations of subsurface using microtremors on the ground surface. Q Rept RTRI Jpn 30: 25-33.
    • (1989) Q Rept RTRI Jpn , vol.30 , pp. 25-33
    • Nakamura, Y.1
  • 48
    • 0002384860 scopus 로고
    • On the amplitude characteristics of microtremor (part 2)
    • (In Japanese with English abstract)
    • Nogoshi M, Igarashi T (1971) On the amplitude characteristics of microtremor (part 2). J Seismol Soc Jpn 24: 26-40 (In Japanese with English abstract).
    • (1971) J Seismol Soc Jpn , vol.24 , pp. 26-40
    • Nogoshi, M.1    Igarashi, T.2
  • 49
    • 0036783621 scopus 로고    scopus 로고
    • Amplification of earthquake ground motion by steep topographic irregularities
    • Paolucci R (2002) Amplification of earthquake ground motion by steep topographic irregularities. Earthq Eng Struct Dyn 31: 1831-1853.
    • (2002) Earthq Eng Struct Dyn , vol.31 , pp. 1831-1853
    • Paolucci, R.1
  • 50
    • 50949131249 scopus 로고    scopus 로고
    • Structural architecture of the central Apennines: Interpretation of the CROP 11 seismic profile from the Adriatic coast to the orographic divide
    • Patacca E, Scandone P, Di Luzio E, Cavinato GP, Parotto M (2008) Structural architecture of the central Apennines: Interpretation of the CROP 11 seismic profile from the Adriatic coast to the orographic divide. Tectonics 27: TC3006.
    • (2008) Tectonics , vol.27
    • Patacca, E.1    Scandone, P.2    Di Luzio, E.3    Cavinato, G.P.4    Parotto, M.5
  • 51
    • 0028666909 scopus 로고
    • Ground-motion amplitude across ridges
    • Pedersen H (1994) Ground-motion amplitude across ridges. Bull Seismol Soc Am 84: 1786-1800.
    • (1994) Bull Seismol Soc Am , vol.84 , pp. 1786-1800
    • Pedersen, H.1
  • 52
    • 77955161088 scopus 로고    scopus 로고
    • Topographic effects on the hill of Nocera Umbra, central Italy
    • doi:10.1111/j.1365-246X.2010.04654.x
    • Pischiutta M, Cultrera G, Caserta A, Luzi L, Rovelli A (2010) Topographic effects on the hill of Nocera Umbra, central Italy. Geophys J Int 2(182): 977-987. doi: 10. 1111/j. 1365-246X. 2010. 04654. x.
    • (2010) Geophys J Int , vol.2 , Issue.182 , pp. 977-987
    • Pischiutta, M.1    Cultrera, G.2    Caserta, A.3    Luzi, L.4    Rovelli, A.5
  • 54
    • 0026299558 scopus 로고
    • Off-fault ground ruptures in the Santa Cruz Mountains, California: Ridge-top spreading versus tectonic extension during the 1989 Loma Prieta earthquake
    • Ponti DJ, Wells RE (1991) Off-fault ground ruptures in the Santa Cruz Mountains, California: Ridge-top spreading versus tectonic extension during the 1989 Loma Prieta earthquake. Bull Seism Soc Am 81: 1480-1510.
    • (1991) Bull Seism Soc Am , vol.81 , pp. 1480-1510
    • Ponti, D.J.1    Wells, R.E.2
  • 56
    • 0036704553 scopus 로고    scopus 로고
    • Can seismic waves be trapped inside an inactive fault zone? The case study of Nocera Umbra, central Italy
    • Rovelli A, Caserta A, Marra F, Ruggiero V (2002) Can seismic waves be trapped inside an inactive fault zone? The case study of Nocera Umbra, central Italy. Bull Seismol Soc Am 92: 2217-2232.
    • (2002) Bull Seismol Soc Am , vol.92 , pp. 2217-2232
    • Rovelli, A.1    Caserta, A.2    Marra, F.3    Ruggiero, V.4
  • 57
    • 0001267087 scopus 로고
    • Diffraction of elastic SH waves by wedges
    • Sánchez-Sesma FJ (1985) Diffraction of elastic SH waves by wedges. Bull Seismol Soc Am 75: 1435-1446.
    • (1985) Bull Seismol Soc Am , vol.75 , pp. 1435-1446
    • Sánchez-Sesma, F.J.1
  • 58
    • 3342973085 scopus 로고
    • Elementary solutions for response of a wedgeshaped medium to incident SH and SV waves
    • Sánchez-Seisma FJ (1990) Elementary solutions for response of a wedgeshaped medium to incident SH and SV waves. Bull Seismol Soc Am 80: 737-742.
    • (1990) Bull Seismol Soc Am , vol.80 , pp. 737-742
    • Sánchez-Seisma, F.J.1
  • 59
    • 0026305524 scopus 로고
    • Diffraction of P, SV, and Rayleigh waves by topographical features: a boundary integral formulation
    • Sánchez-Sesma FJ, Campillo M (1991) Diffraction of P, SV, and Rayleigh waves by topographical features: a boundary integral formulation. Bull Seismol Soc Am 81: 2234-2253.
    • (1991) Bull Seismol Soc Am , vol.81 , pp. 2234-2253
    • Sánchez-Sesma, F.J.1    Campillo, M.2
  • 60
    • 0000645845 scopus 로고
    • A boundary method for elastic wave diffraction: application to scattering of SH waves by surface irregularities
    • Sanchez-Sesma F, Herrera I, Aviles J (1982) A boundary method for elastic wave diffraction: application to scattering of SH waves by surface irregularities. Bull Seismol Soc Am 72: 473-490.
    • (1982) Bull Seismol Soc Am , vol.72 , pp. 473-490
    • Sanchez-Sesma, F.1    Herrera, I.2    Aviles, J.3
  • 61
    • 0030456096 scopus 로고    scopus 로고
    • Directional topographic site response at Tarzana observed in aftershocks of the 1994 Northridge, California, earthquake: implication for mainshock motion
    • Spudich P, Hellweg M, Lee WH (1996) Directional topographic site response at Tarzana observed in aftershocks of the 1994 Northridge, California, earthquake: implication for mainshock motion. Bull Seismol Soc Am 86: 193-208.
    • (1996) Bull Seismol Soc Am , vol.86 , pp. 193-208
    • Spudich, P.1    Hellweg, M.2    Lee, W.H.3
  • 62
    • 73849123559 scopus 로고    scopus 로고
    • L'Aquila (Central Italy) earthquakes: the predecessors of the April 6, 2009 event
    • Tertulliani A, Rossi A, Cucci L, Vecchi M (2009) L'Aquila (Central Italy) earthquakes: the predecessors of the April 6, 2009 event. Seismol Res Lett 80(6): 972-977.
    • (2009) Seismol Res Lett , vol.80 , Issue.6 , pp. 972-977
    • Tertulliani, A.1    Rossi, A.2    Cucci, L.3    Vecchi, M.4
  • 63
    • 79955089234 scopus 로고    scopus 로고
    • Working Group CPTI, INGV, Bologna, Italy, (Last check of the availability: Sept. 2010)
    • Working Group CPTI (2008) Catalogo Parametrico dei Terremoti Italiani, versione 2008 (CPTI08). INGV, Bologna, Italy. http://www. emidius. mi. ingv. it/CPTI/ (Last check of the availability: Sept. 2010).
    • (2008) Catalogo Parametrico dei Terremoti Italiani, versione 2008 (CPTI08)


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.