Penta Geyser is located in the Upper Geyser Basin of Yellowstone and is a part of the Sawmill complex. Penta geyser rarely erupts if the complex is in Sawmill mode where Sawmill is active. In Sawmill mode Penta only erupts a few times a year. When the complex is in Penta-Churn mode it may erupt as often as a few times per day.
Penta Geyser:
Image copyright 1998, Mas Hayakawa. All rights reserved.
Penta Geyser May 2001:
Image copyright 2001, Michael Frazier. All rights reserved.