Delineating a low velocity zone using joint inversion of rayleigh-wave dispersion curve

Padjadjaran Earth Dialogues, International Symposium on Geophysical Issues

Rubaiyn, Al^1 ; Priyono, Awali^2 ; Safani, Jamhir^3

Master Program of Geophysical Engineering, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung

40132, Indonesia^1

Global Geophysics Group, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung

40132, Indonesia^2

Department of Geophysical Engineering, Universitas Halu Oleo, Kampus Hijau Bumi Tridharma, Anduonohu, Kambu, Kota Kendari

93232, Indonesia^3

关键词: Low velocity layers;    Low velocity zones;    Phase-shift method;    Rayleigh-wave dispersion;    Seismic velocities;    Shallow subsurface;    Shear wave velocity;    Site investigations;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/311/1/012077/pdf
DOI  :  10.1088/1755-1315/311/1/012077

来源: IOP

【 摘 要 】

Seismic methods widely used to study the shallow subsurface for different purposes. Analysis of P-wave refraction cannot uniquely determine the seismic velocities as a function of depth when a low velocity layer is present. It is situation commonly encountered in geotechnical site investigation. Utilization of Rayleigh wave dispersion can be uses to determine the structure with existence of low velocity zone. In this study, we discuss efficiency and effectiveness of a joint inversion of Rayleigh wave dispersion curve which combining the genetic algorithm and the Occam's algorithm to delineate a low velocity zone. Numerical test is presented. The shear wave velocity and thickness errors which is the difference between the true and inverted model parameters is used to appraise the value accuracy inversion model. The result provides accurate solution models with is 2.3 % and is 13.4%. Finally, we demonstrates the joint inversion scheme to invert Rayleigh wave dispersion curve which calculated by phase-shift method from a real example data.