noiseMatrix2PdfMatrix: Convert matrix of PSDs to matrix of Probability Density...

In IRISSeismic: Classes and Methods for Seismic Data Analysis

Convert matrix of PSDs to matrix of Probability Density Functions

Description

This function converts a noiseMatrix returned by either psdList2NoiseMatrix or psdDF2NoiseMatrix into a matrix of Probability Density values as defined by McNamara and Boaz 2005.

Usage

noiseMatrix2PdfMatrix(noiseMatrix, lo, hi, binSize)

Arguments

noiseMatrix	a noiseMatrx returned from either psdList2NoiseMatrix or psdDF2NoiseMatrix
lo	lowest frequency bin (power level in dB) for the PDF y-axis (default=-200)
hi	highest frequency bin (power level in dB) for the PDF y-axis (default=-50)
binSize	size in dB of each bin (default=1)

Details

The McNamara and Boaz paper describes creating histograms of the discretized power levels at each frequency bin associated with a set of PSDs. The value in each cell of the PDF matrix is the fraction of the corrected PSDs that have that power level at that frequency bin.

To return a PDF matrix that matches those in the McNamara paper, use the default settings.

Value

A matrix is returned with one row for each power level (-250:-50 dB) and one column for each frequency bin.

Author(s)

Jonathan Callahan [e-mail]

References

Seismic Noise Analysis System Using Power Spectral Density Probability Density Functions (McNamara and Boaz 2005)

See Also

McNamaraPSD, psdDF2NoiseMatrix, psdList, psdPlot, psdStatistics

Examples

## Not run: 
# Create a new IrisClient
iris <- new("IrisClient", debug=TRUE)

# Get seismic data
starttime <- as.POSIXct("2011-05-05", tz="GMT") # 2011.125
endtime <- starttime + 1*24*3600
st <- getDataselect(iris,"IU","GRFO","--","BHE",starttime,endtime)

# Generate power spectral density for each hour long segment
psdList <- psdList(st)

# Convert into corrected "noiseMatrix"
noiseMatrix <- psdList2NoiseMatrix(psdList)

# Convert into McNamara "pdfMatrix"
pdfMatrix <- noiseMatrix2PdfMatrix(noiseMatrix)

# NOTE:  Data need to be flipped and tranposed for the XY axes in the
# NOTE:  image() function to match rows and columns in our pdfMatrix
# Plot pdfMatrix
image(t(pdfMatrix[,ncol(pdfMatrix):1]),
      col=c('gray90',rainbow(9)),
      axes=FALSE)

## End(Not run)

IRISSeismic documentation built on Oct. 16, 2022, 1:09 a.m.