Cascadia northern zone weights incorrect

[pmpowers-usgs]

Late in the 2014 NSHMP development process it was noted (by C.B. Crouse) that the weight being assigned to the Cascade 'Northern Zone' segment model was 0.1 instead of 0.125 (segmented-0.5 * northern-0.25). This resulted in modifications to the cascade combine files as well as Figure 65 in the OFR:

Updates were supplied by @CGS-ruichen, and @mmoschetti-usgs committed the updated combine files to the repository some time ago. For some reason, an earlier Cascadia combine file was used when computing hazard for the first edition of the 2014 model. This issue will be closed without any related commits.

[pmpowers-usgs]

Additional documents related to the Cascadia source model that explain its weights and rates in more detail than was provided in the 2014 NSHM Open-File Report:

• Summary of Cascadia Source Model Implementation.pdf
• Spreadsheet attachment.xlsx
• combine.sub2014_final.docx