scholarly journals A compilation of the geology and measured and estimated shear-wave velocity profiles at strong-motion stations that recorded the Loma Prieta, California, earthquake

1991 ◽  
Author(s):  
T.E. Fumal
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Strong Motion ◽  
Velocity Profiles ◽  
Loma Prieta

Strong Motion Station Characterization and Site Effects during the 1999 Earthquakes in Turkey

2003 ◽  
Vol 19 (3) ◽  
pp. 653-675 ◽  
Author(s):  
Ellen M. Rathje ◽  
Kenneth H. Stokoe ◽  
Brent Rosenblad
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Strong Motion ◽  
Velocity Profiles ◽  
Kocaeli Earthquake ◽  
Amplification Factors ◽  
Motion Data ◽  
Long Period ◽  
Attenuation Relationships

The 1999 Kocaeli and Duzce earthquakes in Turkey generated a moderate amount of strong ground motion data. This paper describes the shear-wave velocity profiles measured at a number of strong motion stations in Turkey using the spectral-analysis-of-surface-waves (SASW) method. The shear-wave velocity profiles from SASW testing compare well with deeper profiles developed by microtremor surface wave inversion, but SASW provides more shear-wave velocity resolution near the ground surface. The developed shear-wave velocity profiles are used to define site classifications for each station. For the Kocaeli earthquake, event-specific attenuation relationships are developed. These relationships show considerable amplification of peak ground acceleration and spectral acceleration (at a period of 0.3 s) at deep soil sites in the far field, but no amplification in the near-fault region. For spectral accelerations at longer spectral periods (1.0 and 2.0 s), amplification is indicated in both the near field and far field. Amplification factors derived from the Kocaeli earthquake strong motion data are generally larger than those used in current attenuation relationships and building codes. The short-period amplification factors derived from the regression decrease with increasing rock motion intensity (PGArock), and the derived long-period amplification factors increase with increasing PGArock. These trends are most likely due to soil nonlinearity. The increase in long-period amplification factors with PGArock is not taken into account in current building codes.

Identification of Engineering Bedrock in Taiwan based on Site Amplification and Velocity Structures of Strong-motion Stations

2020 ◽  
Author(s):  
Che-Min Lin ◽  
Jyun-Yan Huang ◽  
Chun-Hsiang Kuo ◽  
Kuo-Liang Wen
Keyword(s):  
Shear Wave ◽  
Ground Motion ◽  
Wave Velocity ◽  
Earthquake Engineering ◽  
Shear Wave Velocity ◽  
Receiver Function ◽  
Ground Surface ◽  
Strong Motion ◽  
Site Amplification ◽  
Velocity Profiles

<p>There are two kinds of bedrocks that are widely used in seismology and earthquake engineering respectively. The seismology field uses the “seismic bedrock” to define an interface that has a practically lateral extent. The strata deeper than this interface is much more homogeneous in comparison with the shallower one. It is common to set the seismic bedrock within the upper crust has 3000 m/sec of the shear wave velocity. In contrast, the earthquake engineering prefers the shallower interface which dominates the main seismic site amplification, especially the predominant frequency of ground motion. The interface is called “Engineering Bedrock”, which the underlying stratum has the shear wave velocity from 300 to 1000 m/sec for different purposes. But, the reference shear wave velocity of the engineering bedrock is mostly defined as 760 m/sec for ground motion prediction and simulation. In Taiwan, the Central Weather Bureau (CWB) constructed and operates a dense strong-motion network called TSMIP (Taiwan Strong Motion Instrument Program), which provides numerous ground motion data for seismology and earthquake engineering. In our previous studies, the shallow shear wave velocity profiles of over 700 TSMIP stations were estimated by the Receiver Function method. The velocity profiles are from the ground surface to the depth with the shear wave velocity of at least 2000 m/sec. It allows us to compare the theoretical site amplification of the velocity profile of TSMIP stations with their observed one from the seismic records. The variance of fitness between theoretical and observed amplifications through shear wave velocity is analyzed to evaluate which reference velocity can appropriately define the depth of engineering bedrock, where the most site amplification occur beneath, in all of Taiwan. The difference between local geology is also discussed. Finally, an engineering bedrock map is proposed for further applications in earthquake engineering.</p>

scholarly journals Evaluation of liquefaction potentials based on shear wave velocities in Pohang City, South Korea

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yumin Ji ◽  
Byungmin Kim ◽  
Kiseog Kim
Keyword(s):  
South Korea ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Ground Surface ◽  
Velocity Profiles ◽  
Liquefaction Potential ◽  
Attenuation Relationships ◽  
Cyclic Resistance ◽  
Sand Boils

AbstractThis study evaluates the potentials of liquefaction caused by the 2017 moment magnitude 5.4 earthquake in Pohang City, South Korea. We obtain shear wave velocity profiles measured by suspension PS logging tests at the five sites near the epicenter. We also perform downhole tests at three of the five sites. Among the five sites, the surface manifestations (i.e., sand boils) were observed at the three sites, and not at the other two sites. The maximum accelerations on the ground surface at the five sites are estimated using the Next Generation Attenuation relationships for Western United State ground motion prediction equations. The shear wave velocity profiles from the two tests are slightly different, resulting in varying cyclic resistance ratios, factors of safety against liquefaction, and liquefaction potential indices. Nevertheless, we found that both test approaches can be used to evaluate liquefaction potentials. The liquefaction potential indices at the liquefied sites are approximately 1.5–13.9, whereas those at the non-liquefied sites are approximately 0–0.3.

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