Three-dimensional S-wave velocity model of the Bohemian Massif from Bayesian ambient noise tomography

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.

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Three-dimensional lithospheric S wave velocity model of the NE Tibetan Plateau and western North China Craton

Journal of Geophysical Research Solid Earth ◽

10.1002/2017jb014203 ◽

2017 ◽

Vol 122 (8) ◽

pp. 6703-6720 ◽

Cited By ~ 19

Author(s):

Xingchen Wang ◽

Yonghua Li ◽

Zhifeng Ding ◽

Lupei Zhu ◽

Chunyong Wang ◽

...

Keyword(s):

Tibetan Plateau ◽

Wave Velocity ◽

North China Craton ◽

North China ◽

Three Dimensional ◽

Velocity Model ◽

S Wave ◽

Ne Tibetan Plateau

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Antarctic Upper Mantle Rheology

Geological Society London Memoirs ◽

10.1144/m56-2020-19 ◽

2021 ◽

pp. M56-2020-19

Author(s):

E. R. Ivins ◽

W. van der Wal ◽

D. A. Wiens ◽

A. J. Lloyd ◽

L. Caron

Keyword(s):

Wave Velocity ◽

Upper Mantle ◽

Effective Viscosity ◽

Seismic Velocity ◽

Imaging Techniques ◽

Three Dimensional ◽

Velocity Model ◽

Mantle Flow ◽

S Wave ◽

Velocity Changes

AbstractThe Antarctic mantle and lithosphere are known to have large lateral contrasts in seismic velocity and tectonic history. These contrasts suggest differences in the response time scale of mantle flow across the continent, similar to those documented between the northeastern and southwestern upper mantle of North America. Glacial isostatic adjustment and geodynamical modeling rely on independent estimates of lateral variability in effective viscosity. Recent improvements in imaging techniques and the distribution of seismic stations now allow resolution of both lateral and vertical variability of seismic velocity, making detailed inferences about lateral viscosity variations possible. Geodetic and paleo sea-level investigations of Antarctica provide quantitative ways of independently assessing the three-dimensional mantle viscosity structure. While observational and causal connections between inferred lateral viscosity variability and seismic velocity changes are qualitatively reconciled, significant improvements in the quantitative relations between effective viscosity anomalies and those imaged by P- and S-wave tomography have remained elusive. Here we describe several methods for estimating effective viscosity from S-wave velocity. We then present and compare maps of the viscosity variability beneath Antarctica based on the recent S-wave velocity model ANT-20 using three different approaches.

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Crustal and uppermost mantle S-wave velocity structure beneath the Japanese islands from seismic ambient noise tomography

Geophysical Journal International ◽

10.1093/gji/ggs121 ◽

2013 ◽

Vol 193 (1) ◽

pp. 394-406 ◽

Cited By ~ 5

Author(s):

Zhi Guo ◽

Xing Gao ◽

Heng Shi ◽

Weiming Wang

Keyword(s):

Wave Velocity ◽

Ambient Noise ◽

Velocity Structure ◽

S Wave ◽

Ambient Noise Tomography ◽

Uppermost Mantle ◽

Seismic Ambient Noise ◽

Japanese Islands

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Three-dimensional deep S-wave velocity model of the South San Francisco Bay Area obtained from three-component microtremor measurements and microtremor array measurements

10.1190/segam2020-3426922.1 ◽

2020 ◽

Author(s):

Koichi Hayashi ◽

Stefan Burns

Keyword(s):

San Francisco ◽

Wave Velocity ◽

San Francisco Bay ◽

San Francisco Bay Area ◽

Three Dimensional ◽

Velocity Model ◽

S Wave ◽

Bay Area ◽

Array Measurements ◽

Microtremor Measurements

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

Geophysical Journal International ◽

10.1093/gji/ggz537 ◽

2019 ◽

Vol 220 (3) ◽

pp. 1555-1568 ◽

Cited By ~ 2

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.

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