b.guten | R Documentation |
Estimates the parameter of the Gutenberg-Richter law for the magnitude distribution of earthquakes, given a threshold magnitude; it uses moment estimator on transformed data.
b.guten(magn, m0=min(magn))
magn |
a vector of magnitudes coming from an earthquake catalog. |
m0 |
A threshold value. Only values of |
Maximum likelihodd estimation for the Gutenberg-Richter Law:
\log_{10} N(>m) = a - b \ M
where N(>m)
is the number of events exceeding a magnitude m
and a,b
are two parameters: a
is related to the total seismicity rate of the region while b
, to be estimated, should be usually near 1.
Catalog is assumed to be complete (in a certain space-time region) at least for a magnitude m0
,
that is, every earthquake of magnitude at least m0
in that space-time region, is certainly present in the catalog.
b |
estimate of the parameter |
se |
estimate of the standard error of the estimate |
the plot produced by magn.plot
can be used to have an idea, for a given catalog, of the magnitude threshold value.
Marcello Chiodi
Gutenberg, B. and Richter, C. F. (1944). Frequency of earthquakes in California. Bulletin of the Seismological Society of America, 34, 185-188.
magn.plot
data(italycatalog)
b.guten(italycatalog$magn1)
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