R: Get Corner Frequency: Linear Model

get.corner {RSEIS} | R Documentation

## Get Corner Frequency: Linear Model

### Description

Search for low frequency asymptote, corner frequency, and fall off slope of seismic spectrum.

### Usage

    get.corner(INfreq, INspec, dt, f1, f2, PLOT = FALSE, VERBOSE = FALSE)

### Arguments

`INfreq` | frequency vector
`INspec` | spectrum
`dt` | deltaT
`f1` | low frequency for modeling, Hz
`f2` | High frequency for modeling, Hz
`PLOT` | logical, TRUE=plot
`VERBOSE` | TRUE=diagnostics

### Details

This routine does not assume any particular mathematical model. It searches for a three parameters that describe two lines that mimic the displacement spectrum. The search is done via least squares.

### Value

Model of 3 parameters, best fit.

### Author(s)

Jonathan M. Lees<jonathan.lees.edu>

### See Also

brune.doom

### Examples

    data(CE1)

    ##   set frequency range for modeling for this high frequency data
    ##   we use f2 = 50, but for volcano data should be f2<15

    f1 <- 0.01
    f2 <- 50.0

    ##  set up data and parameters
    amp <-  CE1$y
    len2 <- 2*next2(length(amp))
    a <- list(y=amp, dt=CE1$dt)

    Spec <- MTMdisp(a, f1=f1, f2=f2, len2=len2, PLOT=FALSE )

    lspec <- Spec$displ

    ###  get initial estimate of parameters
    xc <- get.corner(  Spec$f , lspec, CE1$dt, f1, f2, PLOT=FALSE)

[Package RSEIS version 3.7-4 Index]