| Eruption | Duration | Interval |
|---|---|---|
| 05 Sep 1976 @ 1840 | 7h 2m | |
| 05 Sep 1976 @ 1138 | 2h 59m | |
| 05 Sep 1976 @ 0839 | 11d 10h 1m | |
| 24 Aug 1976 @ 2238 | 2h 56m | |
| 24 Aug 1976 @ 1942 | 10d 21h 36m | |
| 13 Aug 1976 @ 2206 | 3h 3m | |
| 13 Aug 1976 @ 1903 | 15d 16h 8m | |
| 29 Jul 1976 @ 0255 | 7h 20m | |
| 28 Jul 1976 @ 1935 ie | 3h 5m | |
| 28 Jul 1976 @ 1630 ie | 308d 20h 4m | |
| 23 Sep 1975 @ 2026 | 5h 14m | |
| 23 Sep 1975 @ 1512 | 47d 7h 5m | |
| 07 Aug 1975 @ 0807 | 2h 37m | |
| 07 Aug 1975 @ 0530 ie | 13d 10h 30m | |
| 24 Jul 1975 @ 1900 | 346d 1h 38m | |
| 12 Aug 1974 @ 1722 | 3h 7m | |
| 12 Aug 1974 @ 1415 | 1y 34d 53m | |
| 09 Jul 1973 @ 1322 | 2y 345d 18h 52m | |
| 29 Jul 1970 @ 1830 | 14y 347d 5h 30m | |
| 20 Aug 1955 @ 1200 A |
| Interval Count | 19 |
| Min | 2h 37m |
| Max | 14y 347d 5h 30m |
| Mean | 1y 39d 14h 11m |
| Median | 10d 21h 36m |
| Note ID | Start Time (US/Mountain) | End Time (US/Mountain) | Entrant | Note |
|---|---|---|---|---|
| 13169 | 11 Aug 2019 @ 1210 | --- | bbev | Steamy and gurgling from main and north vents. |
| 7678 | 02 Oct 1974 @ 1800 | --- | research-mab | 10/2/74 Koehn observed & heard Union Geyser erupt from Bear Landing “Observed and heard eruption… sounded like a jet taking off.” {From Shoshone Cove Log Book - transcribed by Rick H- no time known} |