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Seismic response of L’Aquila downtown from comparison between 2D synthetics spectral ratios of SH, P-SV and Rayleigh waves and observations of the 2009 earthquake sequence
Author(s)
Language
English
Obiettivo Specifico
4.1. Metodologie sismologiche per l'ingegneria sismica
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
3/9(2011)
Publisher
Springer
Pages (printed)
761-781
Issued date
February 2011
Alternative Location
Keywords
Abstract
We have studied two velocity-depth models with the aim of outlining the behavior of a velocity reversal in the top layer, which is associated with the stiff Brecce de L’Aquila unit (BrA). In this setting, the SMTH model is topped by a
layer with about 2:1 impedance contrast with the underlying layer while the NORV model
has no velocity reversal. We have simulated the propagation of SH and P-SV wavefields in
the range 0–10 Hz for incidence 0◦ –90◦ . Earthquake spectral ratios of the horizontal and
vertical components at six sites in L’Aquila downtown are compared to corresponding syn-
thetics spectral ratios. The vertical component of P-SV synthetics enables us to investigate a
remarkable amplification effect seen in the vertical component of the recorded strong motion.
Sites AQ04 and AQ05 are best matched by synthetics from the NORV model while FAQ5
and AQ06 have a better match with synthetics spectral ratios from the SMTH model. All
simulations show this behavior systematically, with horizontal and near-horizontal incident
waves predicting the overall pattern of matches more clearly than vertical and near-vertical
incidence. The model inferences are in agreement with new geological data reporting lateral
passages in the top layer from the stiff BrA to softer sediments. Matches are good in terms
of frequency of the first amplification peak and of spectral amplitude: the horizontal compo-nents have spectral ratio peaks predominantly at 0.5 Hz in the simulations and at 0.7 Hz in the
data, both with amplitudes of 4, while the vertical component spectral ratios reach values of
6 at frequencies of about 1 Hz in both data and simulations. The vertical component spectral
ratios are very well matched using Rayleigh waves with incidence at 90◦ . The NORV model
without the velocity reversal predicts spectral ratio peaks for the horizontal components at
frequencies up to 6 Hz. The reversal of velocity acts as a low-pass frequency filter on the
horizontal components reducing the amplification effect of the sediment filled valley.
layer with about 2:1 impedance contrast with the underlying layer while the NORV model
has no velocity reversal. We have simulated the propagation of SH and P-SV wavefields in
the range 0–10 Hz for incidence 0◦ –90◦ . Earthquake spectral ratios of the horizontal and
vertical components at six sites in L’Aquila downtown are compared to corresponding syn-
thetics spectral ratios. The vertical component of P-SV synthetics enables us to investigate a
remarkable amplification effect seen in the vertical component of the recorded strong motion.
Sites AQ04 and AQ05 are best matched by synthetics from the NORV model while FAQ5
and AQ06 have a better match with synthetics spectral ratios from the SMTH model. All
simulations show this behavior systematically, with horizontal and near-horizontal incident
waves predicting the overall pattern of matches more clearly than vertical and near-vertical
incidence. The model inferences are in agreement with new geological data reporting lateral
passages in the top layer from the stiff BrA to softer sediments. Matches are good in terms
of frequency of the first amplification peak and of spectral amplitude: the horizontal compo-nents have spectral ratio peaks predominantly at 0.5 Hz in the simulations and at 0.7 Hz in the
data, both with amplitudes of 4, while the vertical component spectral ratios reach values of
6 at frequencies of about 1 Hz in both data and simulations. The vertical component spectral
ratios are very well matched using Rayleigh waves with incidence at 90◦ . The NORV model
without the velocity reversal predicts spectral ratio peaks for the horizontal components at
frequencies up to 6 Hz. The reversal of velocity acts as a low-pass frequency filter on the
horizontal components reducing the amplification effect of the sediment filled valley.
References
Amoroso S, Del Monaco F, Di Eusebio F, Monaco P, Taddei B, Tallini M, Totani F, Totani G (2010) Campagna
di indagini geologiche, geotecniche e geofisiche per lo studio della risposta sismica locale della città
dell’Aquila: la stratigrafia dei sondaggi (Giugno - Agosto 2010). Report CERFIS n. 1, http:// www.cerfis.
it/ en/ download/ cat_view/ 67- pubblicazioni- cerfis/ 68- reports
Anzidei M, Boschi E, Cannelli V, Devoti R, Esposito A, Galvani A, Melini D, Pietrantonio G, Riguzzi F,
Sepe V, Serpelloni E (2009) Coseismic deformation of the destructive April 6, 2009 L’Aquila earthquake
(central Italy) from GPS data. Geophys Res Let. doi:10.1029/ 2009GL039145
Atzori S, Hunstad S, Chini M, Salvi S, Tolomei C, Bignami C, Stramondo S, Trasatti E, Antonioli A, Boschi
E (2009) Finite fault inversion of DInSAR coseismic displacement of the 2009 L’Aquila earthquake
(central Italy). Geophys Res Let. doi:10.1029/ 2009GL039293
Blumetti AM, Di Filippo M, Zaffiro P, Marsan P, Toro B (2002) Seismic hazard of the city of L’Aquila (Ab-
ruzzo-Central Italy): new data from geological, morphotectonic and gravity prospecting analysis. Stud
Geol Camerti 1:7–18
Bordoni P, Di Giulio G, Haines AJ, Milana G, Rovelli A (2010) Issues in choosing the references to use for
spectral ratios from observations and modeling at Cavola Landslide in Northern Italy. Bull Seism Soc
Am. doi:10.1785/ 0120090116
Chiarabba C et al (2009) The 2009 L’Aquila (central Italy) Mw6.3 earthquake: main shock and aftershocks.
Geophys Res Lett 36:L18308. doi:10.1029/ 2009GL039627
Cirella A, Piatanesi A, Cocco M, Tinti E, Scognamiglio L, Michelini A, Lomax A, Boschi E (2009) Rupture
history of the 2009 L’Aquila (Italy) earthquake from non-linear joint inversion of strong motion and GPS
data. Geophys Res Let. doi:10.1029/ 2009GL039795
De Luca G, Marcucci S, Milana G, Sano‘ T (2005) Evidence of low frequency amplification in the city of
l’Aquila, Central Italy, through a multidisciplinary approach including strong and weak-motion data,
ambient noise, and numerical modeling. Bull Seism Soc Am 95(4):1469–1481
EMERGEO Working Group (2009) Evidence for surface rupture associated with the Mw 6.3 L’Aquila earth-
quake sequence of April 2009 (central Italy). Terra Nova 22: 43–51. doi:10.1111/ j.1365- 3121.2009.
00915
Galli P, Camassi R (eds) (2009) Rapporto sugli effetti del terremoto aquilano del 6 aprile 2009. DPC-INGV
QUEST Team (http:// www.mi.ingv.it/ eq/ 090406/ quest.html)
Goldstein P, Dodge D, Firpo M, Minner L (2003) SAC2000: signal processing and analysis tools for seismol-
ogists and engineers. In: Lee WHK, Kanamori H, Jennings PC, Kisslinger C (eds) Invited contribution
to ‘The IASPEI international handbook of earthquake and engineering seismology’. Academic Press,
London
Gruppo di lavoro MS (2008) Indirizzi e criteri per la microzonazione sismica. Conferenza delle regioni e
provincie autonome. Dipartimento della protezione civile, Roma, vol 3, e Cd-rom
Gruppo di lavoro MS_AQ (2010) La Microzonazione Sismica dell’area aquilana. 2 vol + 1 DVD
Haines AJ, de Hoop MV (1996) An invariant bedding analysis of general scattering problems. J Math Phys
37:3854–3881
Haines AJ, Hulme T, Yu J (2004) General elastic wave scattering problems using an impedance operator
approach—I. Mathematical development. Geophys J Int 159:643–657
Hulme T, Haines AJ, Yu J (2004) General elastic wave scattering problems using an impedance operator
approach—II. Two-dimensional isotropic validation and examples. Geophys J Int 159:658–666
Kennett BLN (1983) Seismic wave propagation in stratified media. Cambridge University Press, Cambridge
Milana G, Azzara RM, Bergamaschi F, Bertrand E, Bordoni P, Cara F, Cogliano R, Cultrera G, Di Giu-
lio G, Duval AM, Fodarella A, Marcucci S, Pucillo S, Régnier J, Riccio G (2011) The contribution
of seismic data in microzonation studies for downtown L’Aquila. Bull Earthquake Eng. doi:10.1007/
s10518- 011- 9246- 6
Pino NA, Di Luccio F (2009) Source complexity of the 6 April 2009 L’Aquila (central Italy) earthquake and
its strongest aftershock revealed by elementary seismological analysis. Geophys Res Let. doi:10.1029/
2009GL041331
Stewart JP, Chiou S, Bray JD, Graves RW, Somerville PG, Abrahamson NA (2001) Ground motion evalu-
ation procedures for performance-based design. Pacific earthquake engineering research center report
2001/09. College of Engineering, University of California, California
Tertulliani A, Arcoraci L, Berardi M, Bernardini F, Camassi R, Castellano C, Del Mese S, Ercolani E, Graziani
L, Leschiutta I, Rossi A, Vecchi M (2010) An application of EMS98 in a medium-sized city: the case of
L’Aquila (Central Italy) after the April 6, 2009 Mw 6.3 earthquake. Bull Earthquake Eng. doi:10.1007/
s10518- 010- 9188- 4
di indagini geologiche, geotecniche e geofisiche per lo studio della risposta sismica locale della città
dell’Aquila: la stratigrafia dei sondaggi (Giugno - Agosto 2010). Report CERFIS n. 1, http:// www.cerfis.
it/ en/ download/ cat_view/ 67- pubblicazioni- cerfis/ 68- reports
Anzidei M, Boschi E, Cannelli V, Devoti R, Esposito A, Galvani A, Melini D, Pietrantonio G, Riguzzi F,
Sepe V, Serpelloni E (2009) Coseismic deformation of the destructive April 6, 2009 L’Aquila earthquake
(central Italy) from GPS data. Geophys Res Let. doi:10.1029/ 2009GL039145
Atzori S, Hunstad S, Chini M, Salvi S, Tolomei C, Bignami C, Stramondo S, Trasatti E, Antonioli A, Boschi
E (2009) Finite fault inversion of DInSAR coseismic displacement of the 2009 L’Aquila earthquake
(central Italy). Geophys Res Let. doi:10.1029/ 2009GL039293
Blumetti AM, Di Filippo M, Zaffiro P, Marsan P, Toro B (2002) Seismic hazard of the city of L’Aquila (Ab-
ruzzo-Central Italy): new data from geological, morphotectonic and gravity prospecting analysis. Stud
Geol Camerti 1:7–18
Bordoni P, Di Giulio G, Haines AJ, Milana G, Rovelli A (2010) Issues in choosing the references to use for
spectral ratios from observations and modeling at Cavola Landslide in Northern Italy. Bull Seism Soc
Am. doi:10.1785/ 0120090116
Chiarabba C et al (2009) The 2009 L’Aquila (central Italy) Mw6.3 earthquake: main shock and aftershocks.
Geophys Res Lett 36:L18308. doi:10.1029/ 2009GL039627
Cirella A, Piatanesi A, Cocco M, Tinti E, Scognamiglio L, Michelini A, Lomax A, Boschi E (2009) Rupture
history of the 2009 L’Aquila (Italy) earthquake from non-linear joint inversion of strong motion and GPS
data. Geophys Res Let. doi:10.1029/ 2009GL039795
De Luca G, Marcucci S, Milana G, Sano‘ T (2005) Evidence of low frequency amplification in the city of
l’Aquila, Central Italy, through a multidisciplinary approach including strong and weak-motion data,
ambient noise, and numerical modeling. Bull Seism Soc Am 95(4):1469–1481
EMERGEO Working Group (2009) Evidence for surface rupture associated with the Mw 6.3 L’Aquila earth-
quake sequence of April 2009 (central Italy). Terra Nova 22: 43–51. doi:10.1111/ j.1365- 3121.2009.
00915
Galli P, Camassi R (eds) (2009) Rapporto sugli effetti del terremoto aquilano del 6 aprile 2009. DPC-INGV
QUEST Team (http:// www.mi.ingv.it/ eq/ 090406/ quest.html)
Goldstein P, Dodge D, Firpo M, Minner L (2003) SAC2000: signal processing and analysis tools for seismol-
ogists and engineers. In: Lee WHK, Kanamori H, Jennings PC, Kisslinger C (eds) Invited contribution
to ‘The IASPEI international handbook of earthquake and engineering seismology’. Academic Press,
London
Gruppo di lavoro MS (2008) Indirizzi e criteri per la microzonazione sismica. Conferenza delle regioni e
provincie autonome. Dipartimento della protezione civile, Roma, vol 3, e Cd-rom
Gruppo di lavoro MS_AQ (2010) La Microzonazione Sismica dell’area aquilana. 2 vol + 1 DVD
Haines AJ, de Hoop MV (1996) An invariant bedding analysis of general scattering problems. J Math Phys
37:3854–3881
Haines AJ, Hulme T, Yu J (2004) General elastic wave scattering problems using an impedance operator
approach—I. Mathematical development. Geophys J Int 159:643–657
Hulme T, Haines AJ, Yu J (2004) General elastic wave scattering problems using an impedance operator
approach—II. Two-dimensional isotropic validation and examples. Geophys J Int 159:658–666
Kennett BLN (1983) Seismic wave propagation in stratified media. Cambridge University Press, Cambridge
Milana G, Azzara RM, Bergamaschi F, Bertrand E, Bordoni P, Cara F, Cogliano R, Cultrera G, Di Giu-
lio G, Duval AM, Fodarella A, Marcucci S, Pucillo S, Régnier J, Riccio G (2011) The contribution
of seismic data in microzonation studies for downtown L’Aquila. Bull Earthquake Eng. doi:10.1007/
s10518- 011- 9246- 6
Pino NA, Di Luccio F (2009) Source complexity of the 6 April 2009 L’Aquila (central Italy) earthquake and
its strongest aftershock revealed by elementary seismological analysis. Geophys Res Let. doi:10.1029/
2009GL041331
Stewart JP, Chiou S, Bray JD, Graves RW, Somerville PG, Abrahamson NA (2001) Ground motion evalu-
ation procedures for performance-based design. Pacific earthquake engineering research center report
2001/09. College of Engineering, University of California, California
Tertulliani A, Arcoraci L, Berardi M, Bernardini F, Camassi R, Castellano C, Del Mese S, Ercolani E, Graziani
L, Leschiutta I, Rossi A, Vecchi M (2010) An application of EMS98 in a medium-sized city: the case of
L’Aquila (Central Italy) after the April 6, 2009 Mw 6.3 earthquake. Bull Earthquake Eng. doi:10.1007/
s10518- 010- 9188- 4
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