Preliminary results of the analysis of site response across the San Gabriel and San Bernardino Basins using ambient-noise spectral-ratio measurements
- Anisha Tyagi (California State Polytechnic University-Pomona) | Margaret Grenier (California State Polytechnic University-Pomona) | Rachel Kreuziger (California State Polytechnic University-Pomona) | Jacob Kays (California State Polytechnic University-Pomona) | Jascha Polet (California State Polytechnic University-Pomona)
- Document ID
- Society of Exploration Geophysicists
- 2018 SEG International Exposition and Annual Meeting, 14-19 October, Anaheim, California, USA
- Publication Date
- Document Type
- Conference Paper
- 2018. Society of Exploration Geophysicists
- Noise, Passive acquisition, Spectral analysis
- 0 in the last 30 days
- 11 since 2007
- Show more detail
The San Gabriel and San Bernardino Basins are sedimentary basins located in southern California that are surrounded by a network of faults and comprised of soft sediments. Sedimentary basins are known to amplify earthquake ground motions and increase their duration. The San Gabriel and San Bernardino Basins are densely populated areas; therefore, it is important to determine site characteristics for seismic hazard mitigation. Furthermore, if a major rupture were to occur on the Southern San Andreas Fault, the San Gabriel and San Bernardino Basins could potentially amplify the ground motion and funnel the energy from the rupture into the Los Angeles Basin (Denolle et al., 2014), acting as a waveguide. Therefore, it is important to better characterize these basins and to understand their resonance period, amplification and site response. Three seismic profiles, containing over 200 threecomponent nodes, were installed across the San Gabriel and San Bernardino Basins in the first quarter of 2017 and collected approximately one month of continuous waveform data. We apply the Horizontal-to-Vertical Spectral Ratio (HVSR) method to the ambient noise waveform data from this experiment. The resulting spectral ratio curves show clear long period peaks (between 2 and 5 seconds) that likely correspond to basin resonance and that indicate significant variation in amplification factors and resonance frequencies across both basins. Preliminary results show these long period peaks for nodes to the South of the Raymond Fault along a profile in the Western part of the San Gabriel Basin, as well as across the central part of this basin. The peak frequencies for the Western profile suggest that the basin is relatively deeper in this area. Nodes in the Southern half of the Chino Basin indicate values for peak frequencies between those measured for the San Gabriel Basin lines. Peak amplitudes vary between 2 and 4.5, which indicates potential for significant ground motion amplification.
Presentation Date: Wednesday, October 17, 2018
Start Time: 1:50:00 PM
Location: Poster Station 14
Presentation Type: Poster
|File Size||2 MB||Number of Pages||5|
Anderson,M.,J.Matti, andR.Jachens,2004,Structural model of the San Bernardino Basin, California, from analysis of gravity, aeromagnetic, and seismicity data:Journal of Geophysical Research: Solid Earth,109,10.1029/2003jb002544.
Day,S.,D.Roten, andK. B.Olsen,2012,Adjoint analysis of the source and path sensitivities of basin- guided waves:Geophysical Journal International,189,1103–1124,10.1111/j.1365-246X.2012. 05416.x.
Denolle,M. A.,E. M.Dunham,G. A.Prieto, andG. C.Beroza,2013,Ground motion prediction of realistic earthquake sources using the ambient seismic field:Journal of Geophysical Research: Solid Earth,118,2102–2118,10.1029/2012JB009603.
Denolle,M. A.,E. M.Dunham,G. A.Prieto, andG. C.Beroza,2014,Strong ground motion prediction using virtual earthquakes:Science,343,399–403,10.1126/science.1245678.
Di Giulio,G.,C.Cornou,M.Ohrnberger,M.Wathelet, andA.Rovellii,2006,Deriving wavefield characteristics and shear-velocity profiles from two-dimensional small-aperture arrays analysis of ambient vibrations in a small-size Alluvial Basin, Colfiorito, Italy:Bulletin of the Seismological Society of America,96,1915–1933,10.1785/0120060119.
Flores-Estrella,H.,S.Yussim, andC.Lomnitz,2006,Seismic response of the Mexico City Basin: A review of twenty years of research:Natural Hazards,40,357–372,10.1007/s11069-006-0034-6.
Geology of the San Gabriel Basin. Watershed, LA County DWP,2005.www.water.ca.gov%2fpubs%2fgroundwater%2fbulletin_118%2fbasindescriptions%2f4-13.pdf&p=DevEx,5068.1.
Graves,R. W.,1995,Preliminary analysis of long-period basin response in the Los Angeles Region from the 1994 Northridge Earthquake:Geophysical Research Letters,22,101–104,10.1029/94gl02894.
Graves,R. W.,A.Pitarka, andP. G.Somerville,1998,Ground-motion amplification in the Santa Monica area: Effects of shallow basin-edge structure:Bulletin of the Seismological Society of America,88,1224–1242,10.1785/0120000510.
Graves,R.,T. H.Jordan,S.Callaghan,E.Deelman,E.Field,G.Juve,C.Kesselman,P.Maechling,G.Mehta,K.Milner,D.Okaya,P.Small, andK.Vahi,2011,Cybershake: A physics-based seismic hazard model for Southern California:Pure and Applied Geophysics,168,367–381,10.1007/s00024-010-0161-6.
Hall,J. F., andJ. L.Beck,1986,Structural damage in Mexico City:Geophysical Research Letters,136,589–592,10.1029/gl013i006p00589.
Lee,E. J.,P.Chen, andT. H.Jordan,2014,Testing waveform predictions of 3D velocity models against two recent Los Angeles earthquakes:Seismological Research Letters,85,2014,1275–1284,10.1785/0220140093.
Ma,S., andG. C.Beroza,2012,Ambient-field Green’s functions from asynchronous seismic observations:Geophysical Research Letters,39,L06301,10.1029/2011GL050755.
Olsen,K. B.,S. M.Day,J. B.Minster,Y.Cui,A.Chourasia,M.Faerman,R.Moore,P.Maechling, andT.Jordan,2006,Strong shaking in Los Angeles expected from a southern San Andreas earthquake:Geophysical Research Letters,33,L07305,10.1029/2005JL025472.
Olsen,K. B.,S. M.Day,L. A.Dalguer,J. E.Mayhew,Y.Cui,J.Zhu, andA.Chourasia,2009,ShakeOut-D: Ground motion estimates using an ensemble of large earthquakes on the southern San Andreas fault with spontaneous rupture propagation:Geophysical Research Letters,36,1–6,10.1029/2008GL036832.
Roten,D.,K. B.Olsen,S. M.Day,Y.Cui, andD.Fah,2014,Expected seismic shaking in Los Angeles reduced by San Andreas fault zone plasticity:Geophysical Research Letters,41,2769–2777,10.1002/2014GL059411.
SESAME European Research Project,2004,Guidelines for the implementation of the H/V spectral ratio technique on ambient vibrations.Retrieved fromhttps://sesame.geopsy.org/Papers/HV_User_Guidelines.pdf.
Wang,F., andT. J.Jordan,2014,Comparison of probabilistic seismic-hazard models using averaging- based factorization:Bulletin of Seismological Society of America,104,1230–1257,10.1785/0120130263.
Wathelet,M.,D.Jongmans,M.Ohrnberger, andS.Bonnefoy-Claudet,2008,Array performances for ambient vibrations on a shallow structure and consequences over Vs inversion:Journal of Seismology,12,1–19,10.1007/s10950-007-9067-x.
Yeats,R. S.,2004,Tectonics of the San Gabriel Basin and Surroundings, Southern California:Geological Society of America Bulletin,116,1158,10.1130/b25346.1.