fmddisc: Analysis of Discontinuities in Frequency Magnitude...

In GRTo: Tools for the Analysis of Gutenberg-Richter Distributions of Earthquake Magnitudes

Description

This function finds significant discontinuities in Frequency Magnitude Distributions (FMD).

Usage

fmddisc(file, header = FALSE, colid = 1, nrep = 200, title = "fmddisc")

Arguments

file	filename of the file to be loaded
header	whether file contains headers or not
colid	field number for the magnitude values in file
nrep	number of replicates for the bootstrap
title	main title for the plot

Details

This function reads magnitude values in the field which number is indicated by colid in file. The function returns values of significant magnitude discontinuities (e. g. deviations from linearity) in the FMD. A bootstrap procedure is used to obtain the 90% confidence interval for magnitude discontinuities. We assumed the distribution of the nrep bootstrap replicates is not skewed. Therefore, the 90% confidence interval is simply formed by taking 5% and 95% quantiles of the bootstrap replicates as the lower and upper bound of the interval respectively. These values and the 50% quantile (median) are returned in a list by the function. The function also returns bootstrap mean and bootstrap standard-error (standard deviation of bootstrap replicate estimates). The bootstrap margin of errors at the 90% normal confidence level is returned as the result of 1.645 \* bootstrap standard-error. The function produces a plot showing the FMD and histograms of magnitude values for the significant discontinuities in the FMD. The plot is stored into a file with name file\_disc.png (png format file). Values of counts in histograms are controlled by the number of replicates nrep that are used.

Value

This function returns a list containing the following components:

quant1	the 5%, 50% and 95% quantiles of the bootstrap replicates for the main discontinuity
valid	the numbers of valid replicates
bmean	the bootstrap mean values
bse	the bootstrap standard-error values
bme	the bootstrap margin of errors values
quant2	the 5%, 50% and 95% quantiles of the bootstrap replicates for the auxiliary discontinuity

Note

Thanks to Scott Kostyshak for telling us about the extra bootstrap package dependency. GRTo version 1.2 fixes this issue.

Author(s)

Daniel Amorese

References

D. Amorese, "Applying a change-point detection method on frequency-magnitude distributions", Bull. seism. Soc. Am. (2007) 97, doi:10.1785\/0120060181

Examples

fmddisc(file=system.file("extdata","IDYLLdeep.data.txt",package="GRTo"),
header=FALSE,colid=15,nrep=200,"FMD mag discontinuities")

GRTo documentation built on May 2, 2019, 6:46 a.m.