Revision History for U.S. Geological Survey Circular 1474	

By the Yellowstone Volcano Observatory

Yellowstone Volcano Observatory 2018 Annual Report

---------------------------------------------------------
Posted online February 3, 2021

--------------------------------------------------------
Revised and reposted March 16, 2021

Added Hebgen Lake to five maps.

Added a footnote to p. 9.

Updated ages of two geologic units on the map on p. 22.

Removed a historical site from the map on p. 26.

Removed a historical chemistry monitoring site from the map on p. 27.

Added three missing references to the References Cited list.