CEUS mag scaling relations

[pmpowers-usgs]

Also noted by @treyapel and @nileshshome

@mpetersen-usgs For the 2014 NSHM, the Somerville (2001) magnitude scaling relation was adopted for gridded/smoothed seismicity sources (point-source distance corrections). What was the justification for doing so while not using this relation also for floating fault ruptures and RLME's?

(Note that only the Charlevoix RLME has an unknown strike and uses WC-length)

cc: @olboyd-usgs @cmueller-usgs @mmoschetti-usgs @haller-usgs @srezaeian-usgs

[pmpowers-usgs]

This inconsistency (as well as with Cascade Mag-Length relations) will be considered in a future release.

Issue moved to nshmp-model-cous-2014 Issue 4