[Geysers] Moats Report on Azure Spring

[sgryc at comcast.net]

>From Will Moats: 





Hello Everyone, 




Ben Hoppe wrote "A group consisting of nine of us (assuming I can count) made a trip to the River Group this morning... However, I will say that contrary to yesterday's report, there was no significant wash or evidence of increased runoff from Azure Spring. So that's that, and onto the Upper Geyser Basin...". 




I completely disagree with the above conclusion. I was the one that reported by radio that Azure Spring must have had a significant eruption based on wash and scoured drainage channels. I also reported that my son Steven and I witnessed a small eruption of Azure Spring which achieved a height of about 2 feet. I recorded on video part of this small eruption. After this small eruption occurred, the water level of Azure Spring dropped about a foot, then recovered about 8 inches by the time we left the area. 




Eruptions of Azure Spring are rare events. However, evidence that a significant eruption of Azure Spring recently occurred is abundantly clear. I will lay out my case below. I have photographs to back my position, but posting them to the listserve would be a problem for those with dial-up access to the web. If you want to see photos, contact me off the listserve. Better yet, maybe I'll include them with an article in the Sput. 




Evidence of a significant eruption: 




1. There are concentric ripple marks around the bank surrounding the edge of the pool of Azure Spring, formed by wave action that I estimate was about 1 foot in height. When was the last time any gazers saw waves on Azure Spring a foot high? Although the small eruption we witnessed caused waves to form on the water surface, they were only about an inch high. These ripple marks, cut into the loose sinter banks, will likely be destroyed by the first heavy rainfall. But I have pictures of their existence. 




2. Plants in low spots surrounding the banks of the pool are dead (brown). Plants along the edge of the top of the bank are also dead because hot water infiltrated into the sinter banks and killed their roots. This suggests that the largest waves were just able to reach the top of the banks, but were not high enough to overtop the banks and kill more extensive areas of vegetation. 




3. The drainage channel leading from Azure Spring shows ample evidence of fresh scouring from a voluminous flow of water. The channel bifurcates several times as it approaches the river and was cut perhaps 4-6 inches deeper in places along the old channel floor. If you examine the channel closely, you will note 1.) the channel sides are vertical along a significant portion of the channel length, and in a places, the sides actually undercut surrounding soil, and 2.) where the water could not cut through the hard sinter at a depth of about 4-6 inches or so below the old channel floor, the channel bottoms have been swept absolutely clean of all loose sediments. Vertical channel sides, and certainly areas where the channel sides undercut loose soil are not going to last long in a place that receives as much rain as Yellowstone. The banks will erode, and the undercut areas will soon collapse. Debris would soon cover the channel bottoms swept clean of sediments. All of this evidence of scouring suggests that Azure Spring had a significant eruption not long ago which released a substantial surge of water down the drainage channel. 




I'm amazed that nine people missed ALL of this evidence. Perhaps others should go have a look. 




As an aside, while at Azure Spring, a small geyser (RVG-4?) erupted for us to see 4 times before it quit, with its water level dropping and starting to recover at about the same time as Azure Spring. Perhaps its activity was related to that of Azure Spring. The geyser is located about 75 feet west of the west edge of Azure Spring. The eruption height was only about 1 foot, and intervals 2-3 minutes. I have both video and a photograph of this geyser in action. 




-- Will Moats 
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