[ghsc-seminars] January 11th: USGS-GHSC Seminar: Professor Bob Herrmann

[Mirus, Benjamin]

*"**Magnitude, moment, and ground motion"*

*Professor Bob Herrmann,*
* University of St. Louis*


The relation between local magnitude and Mw can be empirically determined
with the qualification the local magnitude is a measure of observed ground
motion and not  the source and that moment magnitude is a derived quantity
that depends on an assumed crustal model and source depth. Neither local
nor moment magnitude are easy to determine and their relation to each other
is problematic Using a new method for adapting the IASPEI ML formula to
different regional propagation, the question is whether this technique is
robust enough for operations.  Drawing upon > 1200 ML and Mw estimate,
successes and problems will be highlighted.  Using IRIS archived waveforms
to study earthquakes several years ago permits an investigation of data
sampling – the NX data provide close-in estimates but were not available at
the time of the events.  Even with problems in ML, the ability to estimate
Mw from ML is  required. Can the scatter be understood?

*Thursday, January 11th, 2017*
*10-11 am​  (Mountain Time)*
*USGS, 1711 Illinois Street, Golden, CO*
*Entry Level Seminar Room*

*Note: Please arrive *~5 minutes early* and *bring photo ID* for
airport-style security measures now in place at the USGS building.

Thank you,
GHSC Seminar Committee

Mirus, Ben - bbmirus at usgs.gov
Josh Rigler - erigler at usgs.gov
Oliver Boyd - oboyd at usgs.gov

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