diff --git a/phylogenetic/data/README.md b/phylogenetic/data/README.md
index f711a21..edc7e6d 100644
--- a/phylogenetic/data/README.md
+++ b/phylogenetic/data/README.md
@@ -6,4 +6,77 @@ The primary source of data for this build is GenBank. However, there are instanc
 
 This Zika build incorporates data from https://github.com/blab/zika-usvi/. The sequences and metadata for USVI from that GitHub repository have undergone curation and were uploaded to https://github.com/nextstrain/fauna. Subsequently, they were downloaded as sequences and metadata, and a filter was applied to include only those records not yet submitted to NCBI GenBank. The resulting records are now available as a pair of metadata and sequences files in this directory.
 
-The process of merging the USVI data into the GenBank dataset is facilitated through the `append_usvi`` rule.
\ No newline at end of file
+The process of merging the USVI data into the GenBank dataset is facilitated through the `append_usvi`` rule.
+
+
+Steps to create the `metadata_usvi.tsv` and `sequences_usvi.fasta` files were as follows:
+
+1. Sequences were uploaded to the fauna database following [these instructions](https://github.com/nextstrain/fauna/blob/f9e7955cb4381d5e881c337e005778ed43b7c56c/builds/ZIKA.md#fred-hutch-sequences).
+2. Sequences were downloaded from the fauna database following [these instructions](https://github.com/nextstrain/fauna/blob/5d5a1f3faf06805a5f31e91df2c76b06e6f3bf6a/builds/ZIKA.md#download-from-fauna-parse-compress-and-push-to-s3) and saved as `zika.fasta`
+3. Sequences were ingested from GenBank following [these instructions]() and saved as `sequences.fasta`
+4. [NCBI Blastn](https://www.ncbi.nlm.nih.gov/books/NBK279690/) was used to identify fauna sequences that were not one hundred percent identical to GenBank sequences using the following commnads:
+
+
+```bash
+GENBANK_SEQUENCES=sequences.fasta
+FAUNA_SEQUENCES=zika.fasta
+
+# Create a local blast database
+makeblastdb \
+  -in ${GENBANK_SEQUENCES} \  
+  -dbtype nucl
+
+# Blast fauna against GenBank
+blastn \
+  -db ${GENBANK_SEQUENCES} \
+  -query ${FAUNA_SEQUENCES} \
+  -num_alignments 1 \
+  -outfmt 6 \
+  -out blast_output.txt
+
+# USVI strains that
+# + match at 100%
+# + match at least a 5000nt region (to filter out short substring matches)
+cat blast_output.txt \
+| awk -F'\t' '$1~"USVI" && $3>=100 && $4>5000 , OFS="\t" {print $1}' \
+> USVI_100_match.txt
+
+less USVI_100_match.txt
+# USVI/5/2016|zika|MW165881|2016-10-17|north_america|usvi|saint_thomas|saint_thomas|genbank|genome|Santiago
+# USVI/43/2016|zika|MW165884|2016-07-19|north_america|usvi|saint_thomas|saint_thomas|genbank|genome|Santiago
+# USVI/4/2016|zika|MW165880|2016-10-14|north_america|usvi|saint_thomas|saint_thomas|genbank|genome|Santiago
+# USVI/35/2016|zika|MW165883|2016-09-08|north_america|usvi|saint_thomas|saint_thomas|genbank|genome|Santiago
+# USVI/25/2016|zika|MW165882|2016-09-27|north_america|usvi|saint_thomas|saint_thomas|genbank|genome|Santiago
+
+# USVI strains that are not in the 100 match list
+cat blast_output.txt \
+| awk -F'\t' '$1~"USVI" , OFS="\t" {print}' \
+| grep -Fvf USVI_100_match.txt \
+| awk -F'\t' '{print $1}' \
+| sort | uniq \
+> USVI_not_match.txt
+
+head USVI_not_match.txt
+# USVI/1/2016|zika|VI1_1d|2016-09-28|north_america|usvi|saint_croix|saint_croix|fh|genome|Black
+# USVI/11/2016|zika|VI11|2016-03-22|north_america|usvi|saint_thomas|saint_thomas|fh|genome|Black
+# USVI/12/2016|zika|VI12|2016-11-04|north_america|usvi|saint_croix|saint_croix|fh|genome|Black
+# USVI/13/2016|zika|VI13|2016-08-13|north_america|usvi|saint_thomas|saint_thomas|fh|genome|Black
+# USVI/19/2016|zika|VI19_12plex|2016-11-21|north_america|usvi|saint_croix|saint_croix|fh|genome|Black
+# ...
+```
+
+5. Pull out the corresponding `metadata_usvi.tsv` and `sequences_usvi.fasta` using a combination of [smof](https://github.com/incertae-sedis/smof) and [augur parse](https://docs.nextstrain.org/projects/augur/en/stable/usage/cli/parse.html)
+
+```bash
+# Pulls out sequences based on a match against header strings
+smof grep -f USVI_not_match.txt zika.fasta > usvi.fasta
+
+# Splits file into metadata_usvi.tsv and sequences_usvi.fasta
+augur parse \
+  --sequences usvi.fasta \
+  --output-sequences sequences_usvi.fasta \
+  --output-metadata metadata_usvi.tsv \
+  --fields strain virus accession date region country division city db segment authors url title journal paper_url \
+  --prettify-fields region country division city
+```
+