diff --git a/README.md b/README.md
index 7639a874bdab9f4d9a7175d05c66e6803b70d133..6f6ec6c9dc65fd6d55d64275141f16a4e0488cc2 100644
--- a/README.md
+++ b/README.md
@@ -66,6 +66,41 @@ See the *nshmp-haz* user guide [site specification section][4] for more details
 
 **Suggested citation:**  TBD.
 
+### 2007 Implementation Details (from xml repo v2.1.2; TODO clean)
+
+Notable implementation details (in fortran source and inputs) that set Alaska 2007 apart from
+later COUS models and this updated nshmp-haz implementation of the Alaska model:
+
+* Grid and slab optimization tables use discretization of 2km out to 200km.
+  * nshmp-haz: __discretization = 1km__
+* Grid and slab sources use the Wells & Coppersmith (1994) magnitude-length scaling relation.
+  * nshmp-haz: __slab sources use Youngs et al. (1997)__ (aka 'geomatrix'; consistent with 2014
+    COUS NSHM)
+* Grid and slab sources randomize strike at M≥6.
+  * nshmp-haz: __uses point-source distance corrections for M≥6__ (in relations above; consistent
+    with 2014 COUS NSHM)
+* Ground motion models do not impose one-sided 3σ upper truncation on exceedances.
+  * nshmp-haz: __no change__
+* Other details:
+  * nshmp-haz: __grid source maxDepth = 15 km__
+* Focal mechansim variations are encoded into coefficients supplied with each input file; flavors
+  for strike-slip and mixed strike-slip/reverse were ported from the 2002 COUS model.
+  * nshmp-haz: __point sources generate focal mechanism specific ruptures with appropriate rake
+    that are processed independently, consistent with 2014 COUS NSHM__
+* Aleatory uncertainty was added in the 2002 COUS model and was carried over here as a
+  moment-balanced Gaussian distribution on mMax of M±0.15 discretized over 5 values with σ=0.12.
+  The 2008 COUS model increased the width of the distribution to M±2σ and increased the
+  discretization to 11 values. Both implementations require custom code; the more recent approach
+  is more straightforward with the distribution a function of σ.
+  * nshmp-haz: __uses more recent (11-point; ±2σ) aleatory uncertainty model__
+* Hazard curves are not truncated at 3σ.
+  * nshmp-haz: __no change__
+
+### 2007 Other Notes (from xml repo v2.1.2; TODO clean)
+
+* Consistent with 2008 and 2014 COUS models, slab and grid Gutenberg-Richter MFD magnitudes bins are centered on 0.05; interface MFD bins are centered on 0.1.
+
+
 [1]: https://code.usgs.gov/ghsc/nshmp/nshmp-haz
 [2]: https://code.usgs.gov/ghsc/nshmp/nshmp-haz/-/blob/main/docs/README.md
 [3]: https://www.usgs.gov/programs/earthquake-hazards/seismic-hazard-maps-and-site-specific-data