Surface wave group velocity in the Osaka sedimentary basin, Japan, estimated using ambient noise cross-correlation functions

Measurement of basement seismic resonance frequencies can elucidate shallow velocity structure, an important factor in earthquake hazard estimation. Ambient noise cross correlation, which is well-suited to studying shallow earth structure, is commonly used to analyze fundamental-mode Rayleigh waves and, increasingly, Love waves. Here we show via multicomponent ambient noise cross correlation that the basement resonance frequency in the Canterbury region of New Zealand can be straightforwardly determined based on the horizontal to vertical amplitude ratio (H/V ratio) of the first higher-mode Rayleigh waves. At periods of 1-3 s, the first higher-mode is evident on the radial-radial cross-correlation functions but almost absent in the vertical-vertical cross-correlation functions, implying longitudinal motion and a high H/V ratio. A one-dimensional regional velocity model incorporating a ~ 1.5 km-thick sedimentary layer fits both the observed H/V ratio and Rayleigh wave group velocity. Similar analysis may enable resonance characteristics of other sedimentary basins to be determined. © 2013. American Geophysical Union. All Rights Reserved.

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Waveform inversion of ambient noise cross-correlation functions in a coastal ocean environment

The Journal of the Acoustical Society of America ◽

10.1121/1.4899795 ◽

2014 ◽

Vol 136 (4) ◽

pp. 2156-2156

Author(s):

Xiaoqin Zang ◽

Michael G. Brown ◽

Neil J. Williams ◽

Oleg A. Godin ◽

Nikolay A. Zabotin ◽

...

Keyword(s):

Correlation Functions ◽

Ambient Noise ◽

Cross Correlation ◽

Waveform Inversion ◽

Coastal Ocean ◽

Ocean Environment ◽

Noise Cross Correlation

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Erratum: On seismic ambient noise cross-correlation and surface-wave attenuation

Geophysical Journal International ◽

10.1093/gji/ggaa225 ◽

2020 ◽

Vol 222 (2) ◽

pp. 1090-1092

Author(s):

Lapo Boschi ◽

Fabrizio Magrini ◽

Fabio Cammarano ◽

Mark van der Meijde

Keyword(s):

Surface Wave ◽

Ambient Noise ◽

Cross Correlation ◽

Wave Attenuation ◽

Seismic Ambient Noise ◽

Noise Cross Correlation

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Evaluating Global Tomography Models With Antipodal Ambient Noise Cross‐Correlation Functions

Journal of Geophysical Research Solid Earth ◽

10.1029/2020jb020444 ◽

2021 ◽

Vol 126 (3) ◽

Author(s):

Jun Xie ◽

Risheng Chu ◽

Sidao Ni

Keyword(s):

Correlation Functions ◽

Ambient Noise ◽

Cross Correlation ◽

Noise Cross Correlation

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Velocity structure of the Whataroa Valley using Ambient Noise Tomography

10.26686/wgtn.17064836.v1 ◽

2021 ◽

Author(s):

◽

Andy McNab

Keyword(s):

Rayleigh Wave ◽

Group Velocity ◽

Shear Wave Velocity ◽

Correlation Functions ◽

Ambient Noise ◽

Cross Correlation ◽

Velocity Dispersion ◽

Group Velocity Dispersion ◽

Velocity Model ◽

Ambient Noise Tomography

<p>This thesis applies ambient noise tomography to investigate the shallow structure of the Whataroa Valley. Ambient noise techniques are applied to continuous seismic recordings acquired on 158 geophones deployed during the Whataroa Active Source Seismic Experiment. Despite only having four days of data, a robust shear-wave velocity model is calculated using a phase-weighted stacking approach to improve the cross-correlation functions' signal-to-noise ratios, allowing for robust velocity measurements to be obtained between periods of 0.3 and 1.8\,s. This yields a database of 12,500 vertical component cross correlation functions and the corresponding Rayleigh wave phase and group velocity dispersion curves. Linearised straight-ray tomography is applied to phase and group velocity dispersion measurements at periods ranging from periods of 0.3 to 1.8\,s. The tomography reveals a velocity that decreases from the vicinity of the DFDP-2B borehole to the centre of the valley. This is interpreted to be the geologic basement deepening towards the centre of the valley. A Monte-Carlo inversion technique is used to jointly invert Rayleigh-wave phase and group velocity dispersion curves constructed from phase and group velocity tomography maps of successively higher periods. Linear interpolation of the resulting 1D shear-wave velocity profiles produces a pseudo-3D velocity model of the uppermost 1,000\,m of the Whataroa Valley. Using sharp increases in velocity to represent lithological change, we interpret two velocity contours at 1,150 and 1,250\,m/s as potential sediment-basement contacts. Depth isocontours of these velocities reveal that the basement deepens towards the centre of the valley, reaching a maximum depth of 400 or 600\,m for the 1,150 and 1,250\,m/s velocity contours respectively. These depths indicate strong glacial over-deepening and have implications for future drilling projects in the Whataroa Valley. A sharp velocity increase of 200\,m/s also occurs at 100\,m depth at the DFDP-2B borehole. We interpret this to be a change in sedimentary rock lithology from fluvial gravels to lacustrine silty sands, related to a change in sedimentary depositional environment.</p>

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Ambient noise cross-correlation observations of fundamental and higher-mode Rayleigh wave propagation governed by basement resonance

10.26686/wgtn.13818893 ◽

2021 ◽

Author(s):

Martha Savage ◽

FC Lin ◽

John Townend

Keyword(s):

Rayleigh Wave ◽

Correlation Functions ◽

Rayleigh Waves ◽

Ambient Noise ◽

Cross Correlation ◽

Amplitude Ratio ◽

Sedimentary Basins ◽

Longitudinal Motion ◽

Resonance Frequencies ◽

Noise Cross Correlation

Measurement of basement seismic resonance frequencies can elucidate shallow velocity structure, an important factor in earthquake hazard estimation. Ambient noise cross correlation, which is well-suited to studying shallow earth structure, is commonly used to analyze fundamental-mode Rayleigh waves and, increasingly, Love waves. Here we show via multicomponent ambient noise cross correlation that the basement resonance frequency in the Canterbury region of New Zealand can be straightforwardly determined based on the horizontal to vertical amplitude ratio (H/V ratio) of the first higher-mode Rayleigh waves. At periods of 1-3 s, the first higher-mode is evident on the radial-radial cross-correlation functions but almost absent in the vertical-vertical cross-correlation functions, implying longitudinal motion and a high H/V ratio. A one-dimensional regional velocity model incorporating a ~ 1.5 km-thick sedimentary layer fits both the observed H/V ratio and Rayleigh wave group velocity. Similar analysis may enable resonance characteristics of other sedimentary basins to be determined. © 2013. American Geophysical Union. All Rights Reserved.

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Velocity structure of the Whataroa Valley using Ambient Noise Tomography

10.26686/wgtn.17064836 ◽

2021 ◽

Author(s):

◽

Andy McNab

Keyword(s):

Rayleigh Wave ◽

Group Velocity ◽

Shear Wave Velocity ◽

Correlation Functions ◽

Ambient Noise ◽

Cross Correlation ◽

Velocity Dispersion ◽

Group Velocity Dispersion ◽

Velocity Model ◽

Ambient Noise Tomography

<p>This thesis applies ambient noise tomography to investigate the shallow structure of the Whataroa Valley. Ambient noise techniques are applied to continuous seismic recordings acquired on 158 geophones deployed during the Whataroa Active Source Seismic Experiment. Despite only having four days of data, a robust shear-wave velocity model is calculated using a phase-weighted stacking approach to improve the cross-correlation functions' signal-to-noise ratios, allowing for robust velocity measurements to be obtained between periods of 0.3 and 1.8\,s. This yields a database of 12,500 vertical component cross correlation functions and the corresponding Rayleigh wave phase and group velocity dispersion curves. Linearised straight-ray tomography is applied to phase and group velocity dispersion measurements at periods ranging from periods of 0.3 to 1.8\,s. The tomography reveals a velocity that decreases from the vicinity of the DFDP-2B borehole to the centre of the valley. This is interpreted to be the geologic basement deepening towards the centre of the valley. A Monte-Carlo inversion technique is used to jointly invert Rayleigh-wave phase and group velocity dispersion curves constructed from phase and group velocity tomography maps of successively higher periods. Linear interpolation of the resulting 1D shear-wave velocity profiles produces a pseudo-3D velocity model of the uppermost 1,000\,m of the Whataroa Valley. Using sharp increases in velocity to represent lithological change, we interpret two velocity contours at 1,150 and 1,250\,m/s as potential sediment-basement contacts. Depth isocontours of these velocities reveal that the basement deepens towards the centre of the valley, reaching a maximum depth of 400 or 600\,m for the 1,150 and 1,250\,m/s velocity contours respectively. These depths indicate strong glacial over-deepening and have implications for future drilling projects in the Whataroa Valley. A sharp velocity increase of 200\,m/s also occurs at 100\,m depth at the DFDP-2B borehole. We interpret this to be a change in sedimentary rock lithology from fluvial gravels to lacustrine silty sands, related to a change in sedimentary depositional environment.</p>

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3D crustal structure of the Ligurian Basin revealed by surface wave tomography using ocean bottom seismometer data

Solid Earth ◽

10.5194/se-12-2597-2021 ◽

2021 ◽

Vol 12 (11) ◽

pp. 2597-2613

Author(s):

Felix N. Wolf ◽

Dietrich Lange ◽

Anke Dannowski ◽

Martin Thorwart ◽

Wayne Crawford ◽

...

Keyword(s):

Surface Wave ◽

Group Velocity ◽

Shear Wave ◽

Shear Wave Velocity ◽

Ambient Noise ◽

Cross Correlation ◽

Ocean Bottom ◽

The South ◽

Teleseismic Events ◽

Ligurian Basin

Abstract. The Liguro-Provençal basin was formed as a back-arc basin of the retreating Calabrian–Apennines subduction zone during the Oligocene and Miocene. The resulting rotation of the Corsica–Sardinia block is associated with rifting, shaping the Ligurian Basin. It is still debated whether oceanic or atypical oceanic crust was formed or if the crust is continental and experienced extreme thinning during the opening of the basin. We perform ambient noise tomography, also taking into account teleseismic events, using an amphibious network of seismic stations, including 22 broadband ocean bottom seismometers (OBSs), to investigate the lithospheric structure of the Ligurian Basin. The instruments were installed in the Ligurian Basin for 8 months between June 2017 and February 2018 as part of the AlpArray seismic network. Because of additional noise sources in the ocean, OBS data are rarely used for ambient noise studies. However, we carefully pre-process the data, including corrections for instrument tilt and seafloor compliance and excluding higher modes of the ambient-noise Rayleigh waves. We calculate daily cross-correlation functions for the AlpArray OBS array and surrounding land stations. We also correlate short time windows that include teleseismic earthquakes, allowing us to derive surface wave group velocities for longer periods than using ambient noise only. We obtain group velocity maps by inverting Green's functions derived from the cross-correlation of ambient noise and teleseismic events, respectively. We then used the resulting 3D group velocity information to calculate 1D depth inversions for S-wave velocities. The group velocity and shear-wave velocity results compare well to existing large-scale studies that partly include the study area. In onshore France, we observe a high-velocity area beneath the Argentera Massif, roughly 10 km below sea level. We interpret this as the root of the Argentera Massif. Our results add spatial resolution to known seismic velocities in the Ligurian Basin, thereby augmenting existing seismic profiles. In agreement with existing seismic studies, our shear-wave velocity maps indicate a deepening of the Moho from 12 km at the south-western basin centre to 20–25 km at the Ligurian coast in the north-east and over 30 km at the Provençal coast. The maps also indicate that the south-western and north-eastern Ligurian Basin are structurally separate. The lack of high crustal vP/vS ratios beneath the south-western part of the Ligurian Basin preclude mantle serpentinisation there.

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