Location

San Diego, California

Session Start Date

5-24-2010

Session End Date

5-29-2010

Abstract

Numerical Green’s function is effective for simulating low-frequency ground motions in the near field, in which the whole computing region is divided into a homogenous zone including the source and an inhomogeneous zone (named overburden layer) from the ground surface to a certain depth. In this paper, a procedure to build a 3-D model that properly describes the shear-wave velocity structure of overburden layer and the topography of ground surface was presented. In this procedure, the overburden layer is discretized into finite elements based on the topography of ground surface and buried rock surface; shear-wave velocity data from inversion, surveying line and borehole are assigned to elements according to their locations in the overburden layer. For elements without available velocity data, a Kriging interpolation method based on the spherical variation function model was employed, and dummy borehole is also used to improve the validity of the interpolation based on sparse data. Particularly, block interpolation and interface smooth was suggested for computing region that contains several different geological conditions, such like a sedimentary basin and its vicinity. As an example, the 3-D shear-wave velocity of the Lanzhou sedimentary basin and its vicinity in Gansu, China was modeled using the procedure. Low-frequency ground motions at 10854 surface points in this region was simulated by Numerical Green’s function based on this velocity model, among which ground motions at 7 representative points were compared with those simulated based on horizontal layered velocity model.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Fifth Conference

Publisher

Missouri University of Science and Technology

Publication Date

5-24-2010

Document Version

Final Version

Rights

© 2010 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 24th, 12:00 AM May 29th, 12:00 AM

3-D Modeling of Shear-Wave Velocity for Numerical Green’s Function in Near-Field Ground Motion Simulation

San Diego, California

Numerical Green’s function is effective for simulating low-frequency ground motions in the near field, in which the whole computing region is divided into a homogenous zone including the source and an inhomogeneous zone (named overburden layer) from the ground surface to a certain depth. In this paper, a procedure to build a 3-D model that properly describes the shear-wave velocity structure of overburden layer and the topography of ground surface was presented. In this procedure, the overburden layer is discretized into finite elements based on the topography of ground surface and buried rock surface; shear-wave velocity data from inversion, surveying line and borehole are assigned to elements according to their locations in the overburden layer. For elements without available velocity data, a Kriging interpolation method based on the spherical variation function model was employed, and dummy borehole is also used to improve the validity of the interpolation based on sparse data. Particularly, block interpolation and interface smooth was suggested for computing region that contains several different geological conditions, such like a sedimentary basin and its vicinity. As an example, the 3-D shear-wave velocity of the Lanzhou sedimentary basin and its vicinity in Gansu, China was modeled using the procedure. Low-frequency ground motions at 10854 surface points in this region was simulated by Numerical Green’s function based on this velocity model, among which ground motions at 7 representative points were compared with those simulated based on horizontal layered velocity model.