An Alternative Approach to the SPAC Analysis of Microtremors: Exploiting Stationarity of Noise

Chávez-García, Francisco J.; Rodríguez, Miguel; Stephenson, W. R.

doi:10.1785/0120030179

Cited by 110 publications

(73 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In the frequency domain, the real part of averaged cross-coherence is SPAC coefficient q x; r ð Þ ( Fig. 4a) (CHÁ VEZ-GARCÍA et al 2005;EKSTRÖ M et al 2009) and the SPAC coefficient is equal to J 0 xr c x ð Þ as following equation (AKI 1957;OKADA 2003):…”

Section: Phase Velocity Measurementmentioning

confidence: 99%

See 1 more Smart Citation

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

Xia

Luo

et al. 2015

Pure Appl. Geophys.

View full text Add to dashboard Cite

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.

show abstract

Section: Phase Velocity Measurementmentioning

confidence: 99%

“…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.

View full text Add to dashboard Cite

show abstract

“…Ohori et al 2002;Cho et al 2004Cho et al , 2006aChávez-García et al 2005;Asten 2005, 2007;Wathelet et al 2005Wathelet et al , 2008Tada et al 2006;Köhler et al 2007;Fäh et al 2008;García-Jerez et al 2008;Gouédard et al 2008;Morikawa and Udagawa 2009). The appeal of these methods is due to several properties: their nondestructiveness, for example in comparison to borehole measurements; their ease of use and cost-effectiveness (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Chávez-García et al (2005) present array measurements at the same site for two time periods 8 years apart. However, their main motivation for the second measurement was to check the reliability of their results at low frequencies and extend the observations further in the low-frequency range.…”

Section: Introductionmentioning

confidence: 99%

On the repeatability and consistency of three-component ambient vibration array measurements

Endrun

Ohrnberger

Savvaidis

2009

Bull Earthquake Eng

View full text Add to dashboard Cite

Ambient vibration measurements with small, temporary arrays that produce estimates of surface wave dispersion have become increasingly popular as a low-cost, noninvasive tool for site characterisation. An important requirement for these measurements to be meaningful, however, is the temporal consistency and repeatability of the resulting dispersion and spatial autocorrelation curve estimates. Data acquired within several European research projects (NERIES task JRA4, SESAME, and other multinational experiments) offer the chance to investigate the variability of the derived data products. The dataset analysed here consists of repeated array measurements, with several years of time elapsed between them. The measurements were conducted by different groups in different seasons, using different instrumentations and array layouts, at six sites in Greece and Italy. Ambient vibration amplitude spectra and locations of dominant sources vary between the two measurements at each location. Still, analysis indicates that this does not influence the derived dispersion information, which is stable in time and neither influenced by the instrumentation nor the analyst. The frequency range over which the dispersion curves and spatial autocorrelation curves can be reliably estimated depends on the array dimensions (minimum and maximum aperture) used in the specific deployment, though, and may accordingly vary between the repeated experiments. The relative contribution of Rayleigh and Love waves to the wavefield can likewise change between repeated measurements. The observed relative contribution of Rayleigh waves is generally at or below 50%, with especially low values for the rural sites. Besides, the visibility of higher modes depends on the noise wavefield conditions. The similarity of the dispersion and autocorrelation curves measured at each site indicates B. Endrun (B) · M. Ohrnberger 123 536 Bull Earthquake Eng (2010) 8:535-570 that the curves are stable, mainly determined by the sub-surface structure, and can thus be used to derive velocity information with depth. Differences between velocity models for the same site derived from independently determined dispersion and autocorrelation curves-as observed in other studies-are consequently not adequately explained by uncertainties in the measurement part.

show abstract

“…The SPAC method is usually preferred in the literature to the f-k one, because of its requirement of fewer sensors to achieve the same array resolution and for its better resolution at low frequencies, corresponding to deep materials, for the same array aperture (Asten and Henstridge, 1984;Chávez-García et al, 2005;Okada, 2006;Claprood and Asten, 2010). In this way, Claprood and Asten (2010) propose an alternative method to detect the predominant propagation direction of microtremor wavefield, based on the azimuthal distribution of the mean square of residuals factors for SPAC observations.…”

mentioning

confidence: 99%

Optimizing the number of stations in arrays measurements: Experimental outcomes for different array geometries and the f–k method

Rosa-Cintas¹,

Galiana-Merino²,

Alfaro³

et al. 2014

Journal of Applied Geophysics

View full text Add to dashboard Cite

An Alternative Approach to the SPAC Analysis of Microtremors: Exploiting Stationarity of Noise

Cited by 110 publications

References 23 publications

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

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

On the repeatability and consistency of three-component ambient vibration array measurements

Optimizing the number of stations in arrays measurements: Experimental outcomes for different array geometries and the f–k method

Contact Info

Product

Resources

About