cleanup READMEs

README.md

@@ -21,3 +21,7 @@ decollement-sources/west-flank  | West Flank (extended)   | 5008
 grid-sources/non-summit | Non-Summit - Deep/Shallow       | 5101
 grid-sources/summit     | Summit - Deep/Shallow           | 5100
 zone-sources/caldera    | Caldera Collapse        | 5050
+
+## References
+
+Petersen, M.D, Shumway, A.M., Powers, P.M., Moschetti, M.P., Llenos, A.L., Michael, A.J., Mueller, C.S., Frankel, A.D., Rezaeian, S., Rukstales, K.S., McNamara. D.E., Okubo, P.G., Zeng, Y., Jaiswal, K.S.,, Ahdi, S.K., Altekruse, J.M., and Shiro, B.R., 2021, 2021 U.S. National Seismic Hazard Model for the State of Hawaii, Earthquake Spectra, in press.

volcanic/grid-sources/README.md

@@ -4,6 +4,10 @@ Gridded (and smoothed) seismicity sources are modeled as uniformely distributed
 
 All sub-catalogs were declusterd using nearest-neighbor (`nn`) and Reasenberg (1985; `r85`) algorithms prior to smoothing earthquake rates using a single, adaptive kernel approach.
 
+## Gridded rates
+
+Rates of M = 5.0 earthquakes, `n(m=5)`, given in Table 1 of Petersen et al. (2014) are the Gutenberg-Richter rate of magnitude 5.0 earthquakes derived from the total gridded a-value multiplied by a scale factor for the catalog time period and declustering method. These `n(m=5)` rates are converted to a-values (rate of earthquakes of magnitude 0.0) using ![formula](https://render.githubusercontent.com/render/math?math=n(m)\=10^{a-bm}) for use in grid-source `rate-tree.json` files. Spatial PDFs were created by normalizing the 1960-2019 catalog a-grid file.
+
 ## Grid source rupture set names and IDs
 
 Region     | Depth           | PDF¹ | ID