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Now Some Implications of Deformation Models & Seismicity Observations…

Now Some Implications of Deformation Models & Seismicity Observations…. Moment Rates (10 19 Nm/ yr ). Increase on faults comes from addition of new faults; old faults came down a bit 57% of new fault increase is from three of the new faults.

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Now Some Implications of Deformation Models & Seismicity Observations…

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  1. Now Some Implications of Deformation Models & Seismicity Observations…

  2. Moment Rates (1019 Nm/yr) Increase on faults comes from addition of new faults; old faults came down a bit 57% of new fault increase is from three of the new faults. • Include creep-based moment-rate reductions (default = 0.1). • 57% of Geologic on-fault increase (0.31) is from: Cerro Prieto (0.077  1019 Nm/yr); Mendocino (0.054  1019 Nm/yr); and Brawley (Seismic Zone) alt 1 (0.049  1019 Nm/yr). • On-fault moment rate change for the same faults as used in the UCERF2 model. • UCERF2 value includes both “C-Zones (aseismic)” and “Non-CA Faults” (treated as off fault here). • Relative to the UCERF2 total value of 2.37 1019 Nm/yr, which includes contributions from “C-Zones (aseismic)”. • Assuming a truncated GR distribution with 8.7 M  5 events per year (Appendix L) and a b-value of 1.0

  3. Moment Rates (1019 Nm/yr) Off-fault increases are from 11% to 45% These off-fault moment rates are not used to constrain UCERF3 (but rather provide an implied off-fault aseismcity) • Include creep-based moment-rate reductions (default = 0.1). • 57% of Geologic on-fault increase (0.31) is from: Cerro Prieto (0.077  1019 Nm/yr); Mendocino (0.054  1019 Nm/yr); and Brawley (Seismic Zone) alt 1 (0.049  1019 Nm/yr). • On-fault moment rate change for the same faults as used in the UCERF2 model. • UCERF2 value includes both “C-Zones (aseismic)” and “Non-CA Faults” (treated as off fault here). • Relative to the UCERF2 total value of 2.37 1019 Nm/yr, which includes contributions from “C-Zones (aseismic)”. • Assuming a truncated GR distribution with 8.7 M  5 events per year (Appendix L) and a b-value of 1.0

  4. Deformation Model Moment Rates UCERF2 (2.1) Geologic ABM NeoKinema Zeng UCERF3 Ave 17 10 On fault Mo Rate (Nm/yr) 15 10 Off Fault Total 13 10 +2 log10(Ratio) Ratio to U3 Ave -2

  5. Moment Rates Average Deformation Model UCERF2 Smooth Seismicity Implied UCERF3 Smooth Seismicity Implied (Geologic, Zeng, ABM, & NeoKinema) (Assuming same total moment rate as for Ave DefMod & constant Mmax and b-value) log(Moment Rate)

  6. Smooth Seismicity Divided By Ave Deformation Model UCERF2 UCERF3 log10(ratio)

  7. Smooth Seismicity Divided By Ave Deformation Model • Temporal rate changes • orange/red areas are more active (& green/blue less active) in recent times • Inadequate Declustering • under declustered in orange/red areas (& over declustered in green/blue areas) • Aseismicity • green/blue areas are more aseismic (at least at lower mags); this can’t explain orange/red areas (and we wouldn’t see aseis that only influences larger events like on Creeping SAF) • Mmax Variability • orange/red areas have lower Mmax & green/blue areas have higher Mmax • b-value Variability • orange/red areas have higher, & green/blue have lower b-value • Char MFDs On Faults • where faults appear green/blue; rest of region would need to be a bit more orange/red. • Undetected Earthquakes • in green/blueareas • No real significant differences (given uncertainties in both)? UCERF3 UCERF2 Assumptions log10(ratio)

  8. Smooth Seismicity Divided By Ave Deformation Model • Temporal rate changes • orange/red areas are more active (& green/blue less active) in recent times • Inadequate Declustering • under declustered in orange/red areas (& over declustered in green/blue areas) • Aseismicity • green/blue areas are more aseismic (at least at lower mags); this can’t explain orange/red areas (and we wouldn’t see aseis that only influences larger events like on Creeping SAF) • Mmax Variability • orange/red areas have lower Mmax & green/blue areas have higher Mmax • b-value Variability • orange/red areas have higher, & green/blue have lower b-value • Char MFDs On Faults • where faults appear green/blue; rest of region would need to be a bit more orange/red. • Undetected Earthquakes • in green/blueareas • No real significant differences (given uncertainties in both)? Implied Mmax if both deformation models and smoothed seismicity are correct (assuming GR) UCERF3

  9. Now General Discussion

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