scholarly journals Ambient Noise Tomography for a High-resolution 3D S-Wave Velocity Model of the Kinki Region, Southwestern Japan, using Dense Seismic Array Data

2021 ◽  
Author(s):  
BOKANI NTHABA ◽  
Tatsunori Ikeda ◽  
Hiro Nimiya ◽  
Takeshi Tsuji ◽  
Yoshihisa Iio
Keyword(s):  
High Resolution ◽  
Wave Velocity ◽  
Ambient Noise ◽  
Velocity Model ◽  
Seismic Array ◽  
S Wave ◽  
Ambient Noise Tomography ◽  
Array Data ◽  
Dense Seismic Array

scholarly journals South Ilan Plain High-Resolution 3-D S-Wave Velocity from Ambient Noise Tomography

2016 ◽  
Vol 27 (3) ◽  
pp. 375 ◽  
Author(s):  
Kai-Xun Chen ◽  
Po-Fei Chen ◽  
Li-Wei Chen ◽  
Huajian Yao ◽  
Hongjian Fang ◽  
...  
Keyword(s):  
High Resolution ◽  
Wave Velocity ◽  
Ambient Noise ◽  
S Wave ◽  
Ambient Noise Tomography

Sedimentary structure of the Sichuan Basin derived from seismic ambient noise tomography

2020 ◽  
Author(s):  
Xin Xia ◽  
Zhiwei Li ◽  
Feng Bao ◽  
Jun Xie ◽  
Yutao Shi ◽  
...  
Keyword(s):  
Wave Velocity ◽  
Sichuan Basin ◽  
Ambient Noise ◽  
Large Scale ◽  
Velocity Model ◽  
S Wave ◽  
Ambient Noise Tomography ◽  
Ground Acceleration ◽  
The Sichuan Basin ◽  
Sedimentary Layer

Summary Determining a detailed 3-D velocity model with high resolution for the sedimentary layer in the Sichuan Basin is potentially beneficial both to the industrial oil/gas exploration and earthquake hazards mitigation. In this study, we apply the ambient noise tomography method to construct a 3-D S-wave velocity model. This model focuses on the sedimentary layer of the Sichuan Basin, with a 0.3° × 0.3° grid precision. Dispersion curves of both group and phase velocities of Rayleigh wave at 4 to 40 s periods are utilized, which are extracted from 87 broadband stations in the Sichuan Basin and the surrounding areas. The 3-D model reveals a thick sedimentary layer of the Sichuan Basin with S-wave velocity ranging from ∼2.0 km/s to 3.4 km/s. The sediment thickness in the margins of the Sichuan Basin is generally greater than the typical values of 6–10 km in the central areas due to surrounding orogenic activities, with a maximum depth of ∼13 km in the northwestern margin. Moreover, a prominent low S-wave velocity anomaly in the margins may be caused by the sediment accumulations from large-scale landslides and pronounced denudation of the surrounding orogenic belts. Major geologic units in the sedimentary layer are delineated in this study. The S-wave velocity values within each geologic unit and their bottom interfaces are obtained. Based on our model, we calculate synthetic ground motions for the 2013 Lushan earthquake and obtain the distribution of the peak ground acceleration from the earthquake epicenter to the western Sichuan Basin. The result clearly illustrates the basin amplification effect on the seismic waves.

3-D crustal structure of the Iran plateau using phase velocity ambient noise tomography

2019 ◽  
Vol 220 (3) ◽  
pp. 1555-1568 ◽  
Author(s):  
R Movaghari ◽  
G Javan Doloei
Keyword(s):  
Phase Velocity ◽  
Shear Wave ◽  
Wave Velocity ◽  
Crustal Structure ◽  
Shear Wave Velocity ◽  
Ambient Noise ◽  
Velocity Model ◽  
Central Iran ◽  
Ambient Noise Tomography ◽  
Iran Plateau

SUMMARY More accurate crustal structure models will help us to better understand the tectonic convergence between Arabian and Eurasian plates in the Iran plateau. In this study, the crustal and uppermost mantle velocity structure of the Iran plateau is investigated using ambient noise tomography. Three years of continuous data are correlated to retrieve Rayleigh wave empirical Green's functions, and phase velocity dispersion curves are extracted using the spectral method. High-resolution Rayleigh wave phase velocity maps are presented at periods of 8–60 s. The tomographic maps show a clear consistency with geological structures such as sedimentary basins and seismotectonic zones, especially at short periods. A quasi-3-D shear wave velocity model is determined from the surface down to 100 km beneath the Iran plateau. A transect of the shear wave velocity model has been considered along with a profile extending across the southern Zagros, the Sanandaj-Sirjan Zone (SSZ), the Urumieh-Dokhtar Magmatic Arc (UDMA) and Central Iran and Kopeh-Dagh (KD). Obvious crustal thinning and thickening are observable along the transect of the shear wave velocity model beneath Central Iran and the SSZ, respectively. The observed shear wave velocities beneath the Iran plateau, specifically Central Iran, support the slab break-off idea in which low density asthenospheric materials drive towards the upper layers, replacing materials in the subcrustal lithosphere.

A pilot project of ambient noise tomography on a dense seismic array in Ji’nan urban area

2018 ◽  
Vol 31 (5-6) ◽  
pp. 262-271
Author(s):  
Feng Liang ◽  
◽  
Lei Gao ◽  
Zhihui Wang ◽  
Tao Wang ◽  
...  
Keyword(s):  
Urban Area ◽  
Ambient Noise ◽  
Pilot Project ◽  
Seismic Array ◽  
Ambient Noise Tomography ◽  
Dense Seismic Array

scholarly journals High-resolution 3D shallow crustal structure in Long Beach, California: Application of ambient noise tomography on a dense seismic array

Geophysics ◽  
2013 ◽  
Vol 78 (4) ◽  
pp. Q45-Q56 ◽  
Author(s):  
Fan-Chi Lin ◽  
Dunzhu Li ◽  
Robert W. Clayton ◽  
Dan Hollis
Keyword(s):  
Phase Velocity ◽  
Ambient Noise ◽  
Velocity Structure ◽  
Shear Velocity ◽  
Seismic Array ◽  
Clear Correlation ◽  
Long Beach ◽  
Ambient Noise Tomography ◽  
Station Pair ◽  
Dense Seismic Array

Ambient noise tomography has proven to be effective in resolving shallow earth structure. We applied ambient noise tomography on a dense seismic array in Long Beach, California. The array was composed of more than 5200 stations with an average spacing close to 100 m. Three weeks of passive ambient noise were crosscorrelated between each station pair, which resulted in more than 13.5 million crosscorrelations within the area. Clear fundamental-mode Rayleigh waves were observed between 0.5 and 4 Hz, which were most sensitive to structure above 1-km depth. For each station pair, we applied frequency-time analysis to determine the phase traveltime dispersion, and, for each frequency, we applied eikonal tomography to determine the Rayleigh wave phase velocity map. The eikonal tomography accounted for ray bending by tracking the wavefront and allowed uncertainties to be estimated through statistical analysis. The compilation of phase velocity maps was then used to invert for 3D shear velocity structure. The inverted model showed clear correlation with the known geologic features such as the shallow south–north velocity dichotomy and a deeper fast anomaly associated with the Newport-Inglewood fault zone. Our results can potentially be used to complement traditional active source studies.

Ambient noise tomography across Mount St. Helens using a dense seismic array

2017 ◽  
Vol 122 (6) ◽  
pp. 4492-4508 ◽  
Author(s):  
Yadong Wang ◽  
Fan-Chi Lin ◽  
Brandon Schmandt ◽  
Jamie Farrell
Keyword(s):  
Ambient Noise ◽  
Seismic Array ◽  
Ambient Noise Tomography ◽  
Dense Seismic Array ◽  
Mount St Helens

scholarly journals High-Resolution Crustal S-wave Velocity Model and Moho Geometry Beneath the Southeastern Alps: New Insights From the SWATH-D Experiment

2021 ◽  
Vol 9 ◽  
Author(s):  
Amir Sadeghi-Bagherabadi
Keyword(s):  
High Resolution ◽  
Wave Velocity ◽  
Depth Map ◽  
Velocity Model ◽  
Velocity Profiles ◽  
Dispersion Curves ◽  
Crystalline Basement ◽  
S Wave ◽  
Basement Depth ◽  
External Dinarides

We compiled a dataset of continuous recordings from the temporary and permanent seismic networks to compute the high-resolution 3D S-wave velocity model of the Southeastern Alps, the western part of the external Dinarides, and the Friuli and Venetian plains through ambient noise tomography. Part of the dataset is recorded by the SWATH-D temporary network and permanent networks in Italy, Austria, Slovenia and Croatia between October 2017 and July 2018. We computed 4050 vertical component cross-correlations to obtain the empirical Rayleigh wave Green’s functions. The dataset is complemented by adopting 1804 high-quality correlograms from other studies. The fast-marching method for 2D surface wave tomography is applied to the phase velocity dispersion curves in the 2–30 s period band. The resulting local dispersion curves are inverted for 1D S-wave velocity profiles using the non-perturbational and perturbational inversion methods. We assembled the 1D S-wave velocity profiles into a pseudo-3D S-wave velocity model from the surface down to 60 km depth. A range of iso-velocities, representing the crystalline basement depth and the crustal thickness, are determined. We found the average depth over the 2.8–3.0 and 4.1–4.3 km/s iso-velocity ranges to be reasonable representations of the crystalline basement and Moho depths, respectively. The basement depth map shows that the shallower crystalline basement beneath the Schio-Vicenza fault highlights the boundary between the deeper Venetian and Friuli plains to the east and the Po-plain to the west. The estimated Moho depth map displays a thickened crust along the boundary between the Friuli plain and the external Dinarides. It also reveals a N-S narrow corridor of crustal thinning to the east of the junction of Giudicarie and Periadriatic lines, which was not reported by other seismic imaging studies. This corridor of shallower Moho is located beneath the surface outcrop of the Permian magmatic rocks and seems to be connected to the continuation of the Permian magmatism to the deep-seated crust. We compared the shallow crustal velocities and the hypocentral location of the earthquakes in the Southern foothills of the Alps. It revealed that the seismicity mainly occurs in the S-wave velocity range between ∼3.1 and ∼3.6 km/s.

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