[Geysers] Opal Pool - no eruption

[Ralph Taylor]

There was a mention a week or so ago of a report that Opal Pool in Midway
Geyser Basin had erupted.  Dick Powell and I were there a few days ago doing
our thermal cleaning, and we examined the area and concluded that Opal Pool
did NOT erupt any time recently.  We based this on several observations.  

First, the microbial mats were undisturbed, although a drop in water level
had left some of them above water.  

Second, there was no sign of recent wash in the berm of sinter gravel around
the formation; eruptions send a strong wave to the edges and change the berm
configuration.

Third, markers were not washed.

Fourth, the data logger did not show any unusual temperature fluctuations.

The water level in Opal has changed from no visible water to overflowing and
back during the past few years, largely depending on the overflow from Grand
Prismatic Spring.

So, though I wish I could verify an eruption, I cannot.  I will leave the
data logger there just in case, for the same reason I keep one on Splendid
Geyser--a strong hope that eruptions will resume.

Ralph Taylor