Menu entry MS Prague

Determination of surface wave magnitude. Needs measurement of amplitude of one or more S waves before. These S amplitude measurements are usually done on SRO-LP simulated seismograms. The steps to perform to get an MS magnitude are:

• Make source location of event
• Apply SRO-LP simulation filter
• Measure surface wave amplitude on vertical component (via pseudo phase L, e.g. using Surface-Ampl automatic)
• Call Menu entry MS Prague

The MS magnitudes are determined from all S amplitudes found using the Prague formula:

ms = log10(ampl/period) + 1.66*log10(distance) + 3.3

Depending on the epicentral distance there is a minimum period of the signal used for amplitude measurement. Periods smaller than this minimum period are not accepted.

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