Relations between long-period ground motions and subsurface structures

Abstract Applicability of long-period microtremors in inferring subsurface structure is examined using measurements of microtremors in the northwestern part of the Kanto Plain in Japan. Short-term continuous measurements of long-period microtremors at both sediment and basement sites were taken. A spectral peak at a period of 4 to 5 sec is stable with time, while peaks at periods less than 2 sec are time variant, suggesting a variation of microtremor sources. However, it was found that the spectral ratio between vertical and horizontal microtremors (ellipticity) at each site is stable with time. Good agreement was found between ellipticities of microtremors at the sediment site and those computed for Rayleigh waves in which the structure of the sediments beneath the site was taken into account. We also found that the ellipticities of Rayleigh waves in earthquake ground motions were consistent with those of the microtremors. These comparisons provide strong evidence that long-period microtremors in the area studied consist mainly of Rayleigh waves. The ellipticity of microtremors was investigated by observing microtremors at temporary observation sites in the Kanto Plain where the sediment thickness varied from 0 to 1 km. The subsurface structures were deduced by trial-and-error fitting of observed ellipticities with theoretical ellipticities that were calculated assuming Rayleigh waves. These results show that ellipticity of long-period microtremors is effective for deducing structure from microtremor data at a single site.

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AMPLIFICATION FACTOR OF VERTICAL DISTRIBUTION OF SHEAR FORCE COEFFICIENT FOR SEISMICALLY ISOLATED BUILDINGS CORRESPONDING TO INPUT LEVEL OF DESIGN LONG-PERIOD AND LONG-DURATION GROUND MOTIONS

Journal of Structural and Construction Engineering (Transactions of AIJ) ◽

10.3130/aijs.85.1545 ◽

2020 ◽

Vol 85 (778) ◽

pp. 1545-1553

Author(s):

Masahito KOBAYASHI ◽

Masataka GODA

Keyword(s):

Vertical Distribution ◽

Shear Force ◽

Amplification Factor ◽

Ground Motions ◽

Force Coefficient ◽

Long Period ◽

Long Duration ◽

Seismically Isolated ◽

Input Level

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APPLICABILITY OF AMPLIFICATION FACTOR OF VERTICAL DISTRIBUTION OF SHEAR FORCE COEFFICIENT FOR SEISMICALLY ISOLATED BUILDINGS TO LONG-PERIOD AND LONG-DURATION GROUND MOTIONS

Journal of Structural and Construction Engineering (Transactions of AIJ) ◽

10.3130/aijs.84.617 ◽

2019 ◽

Vol 84 (759) ◽

pp. 617-626

Author(s):

Masahito KOBAYASHI ◽

Kenya ISHIMOTO

Keyword(s):

Vertical Distribution ◽

Shear Force ◽

Amplification Factor ◽

Ground Motions ◽

Force Coefficient ◽

Long Period ◽

Long Duration ◽

Seismically Isolated

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Reply to "Comment on 'Statistical Features of Short-Period and Long-Period Near-Source Ground Motions' by Masumi Yamada, Anna H. Olsen, and Thomas H. Heaton" by Roberto Paolucci, Carlo Cauzzi, Ezio Faccioli, Marco Stupazzini, and Manuela Villani

Bulletin of the Seismological Society of America ◽

10.1785/0120100210 ◽

2011 ◽

Vol 101 (2) ◽

pp. 919-924 ◽

Cited By ~ 1

Author(s):

M. Yamada ◽

A. H. Olsen ◽

T. H. Heaton

Keyword(s):

Ground Motions ◽

Statistical Features ◽

Long Period ◽

Short Period

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Sloshing Response of Floating Roofed Liquid Storage Tanks Subjected to Earthquakes of Different Types

Journal of Pressure Vessel Technology ◽

10.1115/1.4006858 ◽

2012 ◽

Vol 134 (5) ◽

Cited By ~ 4

Author(s):

F. G. Golzar ◽

R. Shabani ◽

S. Tariverdilo ◽

G. Rezazadeh

Keyword(s):

Ground Motions ◽

Far Field ◽

Storage Tanks ◽

Natural Period ◽

Design Spectrum ◽

Long Period ◽

Lateral Forces ◽

Different Types ◽

Hamiltonian Variational Principle ◽

Stress Patterns

Using extended Hamiltonian variational principle, the governing equations for sloshing response of floating roofed storage tanks are derived. The response of the floating roofed storage tanks is evaluated for different types of ground motions, including near-source and long-period far-field records. Besides comparing the response of the roofed and unroofed tanks, the effect of different ground motions on the wave elevation, lateral forces, and overturning moments induced on the tank is investigated. It is concluded that the dimensionless sloshing heights for the roofed tanks are solely a function of their first natural period. Also it is shown that while long-period far-field ground motions control the free board height, near-source records give higher values for lateral forces and overturning moments induced on the tank. This means that same design spectrum could not be used to evaluate the free board and lateral forces in the seismic design of storage tanks. Finally, two cases are studied to reveal the stress patterns caused by different earthquakes.

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