| Date: | 2018-09-12 |
| Time: | 0423 |
| Geyser: | Steamboat |
| Webcam: | No |
| Initial: | No |
| Major/Minor: | Major |
| Duration: | ~55m |
| Standardized Duration: | ~55m |
| Time Entered: | 2018-09-12 04:48:39 |
| Time Updated: | 2018-09-12 22:40:00 |
| Time Uploaded: | 2019-05-13 21:42:39 |
| Entrant: | mhreed |
| Observer: | Demetri S and Mara R for the start, Bill and Carol Beverly soon after |
| Submitted to: | GeyserTimes for iOS |
| Comments: | Summary: initiated by series of three strong minors starting at 0420. Early eruption reached at least 200 feet before steam obscured jetting. Several transitions between full water, mixed phase (sometimes segregated by vent), and steam. See details for duration calculation. // Detailed: Demetri and I began our night watch by 2130. Until the eruption, we relied entirely on the sound of jetting/runoff and what little we could see by starlight to note observations. I noted loud minors with near vertical or vertical jetting from at least one vent at 2312, 2317, 2331, 2352, 0030, 0037, 0048, and 0126. After this time I dozed a bit and stopped recording until a "woohoo" minor at 0254. In the hour leading up to the eruption, runoff became noticeably louder and North jetting became progressively more percussive. South threw in more sustained vertical play between concerted minors. At 0420 we observed a strong minor with volume ("oh my god" to "holy cuss") and lit up the geyser. Two follow-up minors (similar to "false starts" described by previous observers) followed at 0421 and 0422, and ten seconds after jetting initiated at 0423 we had no doubt the eruption was starting. Demetri ran to steerage while I gathered up our yardsale (pro tip: don't do this, even if you don't expect an eruption!) and backed down the ramp from the lower platform to avoid the spray. I could look almost straight up and discern water jetting into my field of vision before the steam obscured everything. Bill and Carol arrived as steam dominated the eruption around 0438 (the runoff channel down to steerage was still flowing but the runoff from North died down). Demetri remembers this to be the loudest part of the eruption. By 0445, it was water-dominated again. Another transition to primarily steam came at 0504. Probably back to water at 0508. At 0510 the vents segregated by phase: North in water and South in steam. North began trying to shut down; jetting stopped and was replaced by percussive bursting At 0512 North vent quit altogether and South entered a high velocity, deep steam phase (I thought this was louder than normal steam phase from both vents). Carol and Demetri reported North Vent gushing as viewed from the upper platform. Bill and I watched North throwing increasingly powerful jets (some were muddy; this was the only muddy water we could see during the entire eruption) until full water phase returned in North to ~150 feet and South steam lessened in intensity (see first attachment). This sequence repeated at 0514. Both vents became steam-dominated again at 0518. I note this as the end of the eruption because runoff from both and North and South vents finally died down. Thanks much to Bill and Carol for their help in watching for phase transitions and confirming that yes, this was actually happening. One more thing of interest: as we were walking back to the parking lot, we could hear the steam phase suddenly stop for a few seconds before restarting with what sounded like some jetting. You can see five of these on the seismic trace starting at 0539 (see second attachment). |
| South Vent in heavy steam while North restarts with some forceful jets at 0514. | ||
| https://image.ibb.co/mZDjfU/YNM_09_12.png | Brief pauses in the steam phase followed by restarts that sounded from afar like they had water show on the seismogram from University of Utah station YNM (located at the Norris Museum). | Entrant: mhreed Time Entered:2018-09-12 22:30:09 Time Updated:2018-09-12 22:31:55 Time Uploaded:2018-09-12 22:30:43 Submitted to: |
Time Entered:2018-09-12 13:36:01
Time Uploaded:2018-09-12 14:07:58
Submitted to:GeyserTimes for Android
Time Entered:2018-09-12 19:16:39
Time Uploaded:2018-09-12 19:16:41
Submitted to:GeyserTimes for Android