A Method to Estimate Phase Velocities of Rayleigh Waves Using Microseisms Simultaneously Observed at Two Sites

Morikawa, Hitoshi; Sawada, Sumio; Akamatsu, Junpei

doi:10.1785/0120030020

Cited by 58 publications

(33 citation statements)

References 10 publications

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“…In order to estimate the subsurface S-wave velocity at the Itoiz dam, we performed a field campaign in May 2009 to record seismic noise. We computed the coherence among the signáis recorded in pairs of stations which were separated distances from 4.5 m up to 150 m. Thus, using the two stations spatial autocorrelation method (see, e.g., MORIKAWA et al 2004;CHÁVEZ-GARCÍA et al 2005; CHÁVEZ- GARCÍA and LUZÓN 2005;RAPTAKIS and MAKRA 2010), we computed a phase velocity dispersión curve for Rayleigh waves, which was inverted using the computer codes by HERRMANN (1987) to obtain the S-wave velocity model for the subsurface soil at Itoiz dam. In the inversión process we considered one fixed layer with 30 m depth overlaying the halfspace.…”

Section: Geological and Geotechnical Conditionsmentioning

confidence: 99%

Seismic Hazard and Ground Motion Characterization at the Itoiz Dam (Northern Spain)

Rivas-Medina

Santoyo

Luzón

et al. 2011

Pure Appl. Geophys.

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Abstract-This paper presents a new hazard-consistent ground motion characterization of the Itoiz dam site, located in Northern Spain. Firstly, we propose a methodology with different approximation levéis to the expected ground motion at the dam site. Secondly, we apply this methodology taking into account the particular characteristics of the site and of the dam. Hazard calculations were performed following the Probabilistic Seismic Hazard Assessment method using a logic tree, which accounts for different seismic source zonings and different ground-motion attenuation relationships. The study was done in terms of peak ground acceleration and several spectral accelerations of periods coinciding with the fundamental vibration periods of the dam. In order to estímate these ground motions we consider two different dam conditions: when the dam is empty (T = 0.1 s) and when it is filled with water to its máximum capacity (T = 0.22 s). Additionally, seismic hazard analysis is done for two return periods: 975 years, related to the project earthquake, and 4,975 years, identified with an extreme event. Soil conditions were also taken into account at the site of the dam. Through the proposed methodology we deal with different forms of characterizing ground motion at the study site. In a first step, we obtain the uniform hazard response spectra for the two return periods. In a second step, a disaggregation analysis is done in order to obtain the controlling earthquakes that can affect the dam. Subsequently, we characterize the ground motion at the dam site in terms of specific response spectra for target motions defined by the expected valúes SA (7) of T = 0.1 and 0.22 s for the return periods of 975 and 4,975 years, respectively. Finally, synthetic acceleration time histories for earthquake events matching the controlling parameters are generated using the discrete wave-number method and subsequently analyzed. Because of the short relative distances between the controlling earthquakes and the dam site we considered finite sources in these computations. We conclude that directivity effects Special issue on Deformation and Gravity Change: Indicators of Isostasy, Tectonics, Volcanism and Climate Change PAGEOPH.should be taken into account as an important variable in this kind of studies for ground motion characteristics.

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Section: Geological and Geotechnical Conditionsmentioning

confidence: 99%

Seismic Hazard and Ground Motion Characterization at the Itoiz Dam (Northern Spain)

Rivas-Medina

Santoyo

Luzón

et al. 2011

Pure Appl. Geophys.

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“…are used for obtaining these parameters. The methods have been used by numerous researchers [2,3,4,5,1,13,14,15].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Shear Wave Velocity and Predominant Period Properties of Bornova Plain (IZMIR) and Its Surroundings

Pamuk¹,

Özdağ²,

Tunçel³

et al. 2017

IOSR JAGG

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“…Sensor-array was simplified into line (CHÁ VEZ-GARCÍA et al 2006;MARGARYAN et al 2009) and even only two sensors (MORIKAWA et al 2004; CHÁ VEZ-GARCÍA et al 2005). It has been demonstrated that reliable Rayleigh-wave phase velocities would be calculated with two sensors using SPAC method (BOSCHI et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Potential Misidentification of Love-Wave Phase Velocity Based on Three-Component Ambient Seismic Noise

Xia

Luo

et al. 2015

Pure Appl. Geophys.

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People have calculated Rayleigh-wave phase velocities from vertical component of ambient seismic noise for several years. Recently, researchers started to extract Love waves from transverse component recordings of ambient noise, where ''transverse'' is defined as the direction perpendicular to a greatcircle path or a line in small scale through observation sensors. Most researches assumed Rayleigh waves could be negligible, but Rayleigh waves can exist in the transverse component when Rayleigh waves propagate in other directions besides radial direction. In study of data acquired in western Junggar Basin near Karamay city, China, after processing the transverse component recordings of ambient noise, we obtain two energy trends, which are distinguished with Rayleigh-wave and Love-wave phase velocities, in the frequency-velocity domain using multichannel analysis of surface waves (MASW). Rayleigh waves could be also extracted from the transverse component data. Because Rayleigh-wave and Love-wave phase velocities are close in high frequencies ([0.1 Hz), two kinds of surface waves might be merged in the frequency-velocity domain. Rayleigh-wave phase velocities may be misidentified as Love-wave phase velocities. To get accurate surface-wave phase velocities from the transverse component data using seismic interferometry in investigating the shallow geology, our results suggest using MASW to calculate real Love-wave phase velocities.

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A Method to Estimate Phase Velocities of Rayleigh Waves Using Microseisms Simultaneously Observed at Two Sites

Cited by 58 publications

References 10 publications

Seismic Hazard and Ground Motion Characterization at the Itoiz Dam (Northern Spain)

Seismic Hazard and Ground Motion Characterization at the Itoiz Dam (Northern Spain)

Investigation of Shear Wave Velocity and Predominant Period Properties of Bornova Plain (IZMIR) and Its Surroundings

Potential Misidentification of Love-Wave Phase Velocity Based on Three-Component Ambient Seismic Noise

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