Recent Instrumental Magnitude Issuesor

Magnitude: the Necessary Evil of Statistical Seismology

Andy Michael

Does this affect UCERF3?Still in reprocessing mode.Compute rates for M≥4, little affect thereCompute b-values with smaller events, could affect that

Do we need to recompute b-value with smaller events?Is there agreement that b = 1 in California (at least southern Cal.)?

Tormann et al.

Concluded that:remapping of magnitudes and computation of a result

(e.g. b-value) must be done many times and then take the mean of the result.

declustering should be done before remapping so that spatially and temporally localized magnitude behavior is maintained.

UCERF3 plans: do remapping if we need to use small event magnitudes.

UCERF4 plans: hope they are done reprocessing magnitudes!