Re: nee - W wie moment (ist doch klar *gg*)

Geschrieben von franz_liszt am 10. Oktober 2002 19:05:21:

Als Antwort auf: Re: nee ernsthaft geschrieben von mica am 10. Oktober 2002 18:49:55:

Hallo mica,

nach einem Mittelwert, der für Maximalwerte steht, musste ich doch mal suchen. *g*

Hier die Erklärung von der USGS-Seite
http://wwwneic.cr.usgs.gov/neis/general/handouts/so_many_magnitudes.html

Gruß franz_liszt


Why Are There So Many Earthquake Magnitude Scales?

Earthquake size, as measured by the Richter Scale is a well known, but not well understood, concept. What is even less well
understood is the proliferation of magnitude scales and their relation to Richter's original magnitude scale. The idea of a
logarithmic earthquake magnitude scale was first developed by Charles Richter in the 1930's for measuring the size of
earthquakes occurring in southern California using relatively high-frequency data from nearby seismograph stations. This
magnitude scale was referred to as ML, with the L standing for local. This is what was to eventually become known as the
Richter magnitude.

As more seismograph stations were installed around the world, it became apparent that the method developed by Richter was
strictly valid only for certain frequency and distance ranges. In order to take advantage of the growing number of globally
distributed seismograph stations, new magnitude scales that are an extension of Richter's original idea were developed. These
include body-wave magnitude, mb, and surface-wave magnitude, MS. Each is valid for a particular frequency range and type
of seismic signal. In its range of validity each is equivalent to the Richter magnitude.

Because of the limitations of all three magnitude scales, ML, mb, and MS, a new, more uniformly applicable extension of the
magnitude scale, known as moment magnitude, or MW, was developed. In particular, for very large earthquakes moment
magnitude gives the most reliable estimate of earthquake size. New techniques that take advantage of modern
telecommunications have recently been implemented, allowing reporting agencies to obtain rapid estimates of moment
magnitude for significant earthquakes.

2002/10/10 12:29:35 1.30S 133.91E 10.0 6.0 A IRIAN JAYA REGION, INDONESIA
2002/10/10 12:28:25 1.48S 133.97E 10.0 6.7 A IRIAN JAYA REGION, INDONESIA
2002/10/10 12:27:52 1.47S 134.17E 10.0 5.5 A IRIAN JAYA REGION, INDONESIA
2002/10/10 10:50:20 1.71S 134.16E 10.0 7.6 A IRIAN JAYA REGION, INDONESIA



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