Seattle fault weights and rates

[pmpowers-usgs]

The Seattle fault is modeled as having three possible strands in the geologic model; only the northern strand is included with the geodetic source models (see nshmp-haz-fortran #32).

In the geologic model, the characteristic rate of the northern strand is assigned the a-priori 5000yr. rate and the middle and southern strands are assigned a negligible 10-million year rate. The GR rates for all three strands, however, are equal. Why?

[pmpowers-usgs]

Per @haller-usgs:
We made the change to three traces in 2008. Those records show that the middle and northern were only gr input, like the attached.
seattleFZ.txt

[pmpowers-usgs]

Given the complexity of estimating the recurrence rate on the Seattle Fault and variants, it was decided not to use geodetic slip rates. However, perhaps they should be considered, for consistency with all other WUS faults, possibly while imposing rate maxima in the geodetic inversions.

[pmpowers-usgs]

The Seattle and other exceptional faults will be revisited in the next update to the geodetic models.