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Observations for 2023 September 27


Another side trip to watch an hour or so of Strokkur eruptions. Today it was raining but the wind wasn't as strong. Also early enough that we missed the tours. (although tour season seems to be pretty much over.)

In a series of fourteen eruptions, we saw a couple of two strong burst eruptions, along with along with at least three weak eruptions. The second burst both came about 20 seconds after the first, when it looked like the pool was just trying to quietly refill. The weak eruptions were followed by short intervals, in one case well less than two minutes, while it was ten minutes following the two bursts. Most of the other intervals were around five to seven minutes.


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Observations for 2023 September 26


First we revisited Littli Geyser at Gamla Laugin/Secret Lagoon in Fluðir. While it was dry, it was also overcast and extremely windy (as in having to pay attention to the gusts or be blown over.)

The activity has changed a bit since the last visit three weeks ago. This time we saw six major eruptions from 9 to 12 minutes apart. The four eruptions for which I got a duration all lasted 38 seconds. In all cases the vent drained after the eruption as after the major eruptions in our previous visit.

Then it was on to Haukadalur. It's my opinion that the wind was having an adverse effect on Strokkur. We saw a number of weak eruptions, some only a couple of meters high. The intervals seemed longer also. That the runoff channel from the pool was exactly downwind could easily explain the changes.

While we did see some two burst eruptions, only once was the second burst powerful. The one three burst we saw had a boil up for the second, then a weak third burst.

I did finally get to see a full eruption of Alfaauga. I waited about half an hour, with overflows of increasing intensity occurring every eight minutes or so. Before the eruption there was strong conventing over the vent and some boiling up, but no splashes. Then an overflow continued and there was an eruption lasting just over two minutes. When it appeared that the pool had dropped down to the previous level between the overflows, I assumed I had seen the major eruption and left. (By then had been out in the wind for over 2-1/2 hours, and time to head in.) Just under two hour earlier I had caught the end of another eruption, but I have no idea if those were consecutive.

Behind and to the left/west of Alfaauga was a pool with water level just below the rim. During my wait, at one point the pool was full and pulsating. Then the next time I looked, it was back down. Not sure of the name or activity of this feature.


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Observations for 2023 September 25


Revisited Hveragerði today, in order to visit some new areas and the revisit the activity there. The weather cooperated, as it wasn't too windy, there was no rain, and the sun even came out for a while, allowing for a backlit eruption video.

Found the locations of Grýla and Leppaluði, a couple of boreholes which erupted years ago. Grýla has its own little turnout along the road with a warning sign, even though it was overgrown and not at all steaming, and obviously not active in a long time. A 5cm wide hole in a rock, years ago it could be induced to erupt up to 10m high. Leppaluði is a circular concrete platform about 5m across that has been filled in, and also does not steam. But between it and the river was a small area of what appeared to be sinter gravel.

Farther north along the road is the Gufudalur golf course. Up on the hillside are several areas of thermal activity. In a ravine just outside are a couple of mudpot like features. In the course itself, between a couple of the hole is a thermal pond in which there was a spouter active. There's a sign, "Fallreitur" in front of it, which may be the name, or a warning for golfers. This feature really can only be see on the uphill side, and consists of an opening in a pennisula in the pond. Nearby were a couple of other muddy vents. (It seems this course and Arikikapakapa in Rotorua are the only courses with geothermal hazards.)

Farther up the hillside were another fairly dry mudpot and an old wellhead steaming away. I could not find the features Dirk Niermann calls "Lava Pool" and "Rey-8" and "Rey-9". Also did not try to locate Littli Geyser or Gosi I and II, as I couldn't find good descriptions of their locations. Seems Littli was up near the Agricultural Station we passed by on the way to hillside features the last visit.

We also revisited the Hveragerði Geothermal Park, mostly to see the eruptions of Eilifur Goshver/Eternal Geyser. This feature was nice an regular while we were there, with intervals within a few seconds of 20m15s. A quick burst of steam to 10 meters, but quite entertaining. The pool near the entrance also became active with eruptions when I was able to observe it.

There are reports of this feature only becoming active around 2016, and on the Apple Maps satellite view, there's a suspicious rectangular object located at that location. These satellite maps are several years old, based on the various new roads missing on them. The Google Maps satellite view shows a steaming area.


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Observations for 2023 September 17


South of Húsavík is another Hveravellir. This one used to have several geysers, but all but one has been replaced by greenhouses.

The remaining geyser is Ystihver, a large raised bowl at the base of a hillside. It's about ten meters across, superheated and has been altered in several ways over the last century. There is a drain pipe which keeps the water level just below the rim. There are multple channels for the runoff.

Ystihver erupting

The activity itself consists of periods of calm followed by a heavy boil or bursting. Some of the bursting can reach four meters high, and start with an explosive bubble. These eruptions put water out over the entire rim, and there are catch basins which we never saw water reach them, so it must be capable of even stronger activity on occasion.

On the south side is a concrete structure which has enclosed a small boiling feature, Strokkur. A couple of other geysers were similarly enclosed and are part of the greenhouse complex to the southwest. To the north are a couple of pyramids which contain well heads which are used to supply hot water to the town of Húsavík.


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Observations for 2023 September 16


Today we visited Hverir, east of Myvatn in the far north. This is a place of mudpots, fumaroles and sulphur depositing solfataras.

Upon leaving the (paid) parking lot, the first thermal feature encountered is a watery mudpots with several areas splashing up about 1/2 meter. It lies at the bottom of a dominant feature of the area, a low scarp along which most of the solfataras are located. This scarp is about 100 meters long. Behind it, to the east are several large steaming mounds, which are the remains of boreholes drilled while exporing for geothermal energy.

West of the scarp are several distinct grouping of mudpots, ranging is style from the watery to the thick. All consist of a gray mud, in contrast to the reddish brown surface mud.

The largest, southern group has a number of spouters along the northern boundary, as well as some large muddy craters.

Up on the hillside of Namafjall are deep ravines from which a small trickle of clear water runs down toward the mudpots. Did not explore up that way, as it was a cool day and there was little steam visible up there.

Mudpots at Hverir

Afterwards we had a wet, windy visit to Leirhnjúkur, which is a new thermal area which formed as part of the activity of Krafla in the 1980s. There is a large colloidal pool up on the hillside, with some spouters along the uphill shore and mudpots sharing the pools basin.

We also stopped at the thermal shower along the road south of the Krafla powerplant.


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Observations for 2023 September 09


Today we spent about an hour at Deildartunguhver, a tiny thermal area northeast of Reyjavik. It consists of a single, wide fissure about 50 meters long that pours out boiling water from 10 major vents and numerous smaller cracks. It has been culturally modified to provide hot water for heating districts to the west.

(For identification purposes, I've tried to follow the numbering found in Niemann at Volcanic Springs. Unfortunately, he does not provide a map or photos of all the vents. I counted 10 vents, and based on his photo of #9, I think #10 became active after his visit.)

The vents are located in a wall at the base of Hverahóll, in two parallel lines. Some are about 1/2 meter up the side of the wall. Others are pools in the runoff channel, which eventually flows into the thermal district's intake.

The vents seem to be split into two groups, with five in each. Several The northnermost of the southern group, #5, is a pool in which I saw only occasional splashes. The rest of them spout continuously up to two meters (maybe even three) high from a crack in the wall.

Deildartunguhver vents, 2023 Sep 09. Video by H.Koenig

The southernmost of the northern group, #6 is a geyser. It is a hole in the wall which spouts about 25-40cm most of the time. Every two to three minutes the activity increases in strength and the height approaches two meters. This continues for only a few seconds, then all activity and overflow ceases. The water in the vent drops from sight for a few seconds, then splashes start up down in the vent and the cycle continues.

Deildartunguhver Vent #6, 2023 Sep 09. Video by H.Koenig

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Observations for 2023 September 08


Last night the intention was to go out and take a look around Hveravellir for an hour or so before leaving. But overnight, not only did it start to rain, but there were winds up to 50mph. And that weather did not go away by dawn. So other than seeing steam from Gjósandi from our room window, I didn't see anything out there.

But since we were passing by, we had to stop in to see Strokkur again. The weather was not much better, but at least we only had a few showers in the 45 minutes we were at Haukadalur. Strokkur was not very cooperative. We only saw one burst eruptions, and most of them were weak. Two were so bad that I'd consider them to almost be false starts, if they weren't followed by normal eruption intervals. Maybe the weather had an effect, but that paper I mentioned yesterday doesn't mention any such effects.

Strokkur Geyser, 2023 September 08 12:12:45. Video by H.Koenig.

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Observations for 2023 September 07


Update: Added some details on H-208h, an erupting feature near Öskarhóll.

Spent the day observing the thermal activity at Hveravellir. This is an area for those who like little sputs and spouters. As mentioned yesterday, there are a lot of little features here which show true eruptive activity. Every hole seems to sputter. Many seem to be perpetual spouters, but there were also a number where the activity would cease and restart, making them true geysers.

There was one geyser that could be timed. This is the small geyser Gjósandi, east of the large pool Heimilishver (Bóluhver). This geyser appears to be pretty regular, with intervals of about 40 seconds and durations of from 8 to 12 seconds. Most bursts were only 1.5 meters high, but there were some well over eye level, putting them around 2.5 meters.

Gjosandi Geyser, Hveravellir

Heimilishver (Bóluhver) also shows eruptive bursts, but most of the time this large pool has a heavy, pulsating overflow over much of its rim. On occasion, there would be bursts up to 1/2 meter from it. It looks like it is trying to have a larger eruption, and never quite succeeding. Between it and the walkway there is a large hole that appears to be a collapse in the terraces surrounding the vent. This vent also splashed, but did not seem to be related to its neighbor.

Heimilishver (Bóluhver), Hveravellir

Down the walkway a bit are a series of small sputtering holes, including several under the walkway. Again, these features seem to die down on occasion.

Sput under boardwalk, Hveravellir

The start of activity at Rauðihver seems to be recent. Surrounding it are large wash zones with dead and dying grass. Some of the layers of the formation have been ripped up and pulverized. Rauðihver is fascinating to watch, as the whole pool pulsates over the vent, while thumps can be heard from the pool just before the larger bursts. These bursts of murky, gray water can be thrown as much as two meters high, and come along every minute or two.

Rauðihver, Hveravellir 2023. September 07. Video by H.Koenig.

There are a couple of well defined cones-- Öskarhóll and Fagrihver. Öskarhóll is the larger cone, which at the top has a weak fumarole. A century ago, it was a strong, noisy fumarole. Based on the little terraces down the northeast side, I would suppose that at some time in its past it gently overflowed for a long time. The second cone, Fagrihver, is completely dead, with no steam despite being a cool, humid day.

Öskarhóll, Hveravellir
Gamli Fagrihver (Öskarhóll in background), Hveravellir

To the west of Öskarhóll is a pool for which I can't find any previous mention. It is a well defined pool about three meters across. It splashes continuously up to two meters high, and doesn't look all that recent.

Update: Further research shows this as feature H-208h. A few years ago it was a smaller collapse feature, which turned into a muddy splashing hole. Its gotten larger and clearer based on various online videos I've found.

H-208h near Öskarhóll, Hveravellir

To the east are the pools Grænihver and Bláhver. The latter is a murky pool, while the former is a larger pool that overflows heavily and occasionally splashes. Beyond it and down the slope are a series of smaller features, all of which were splashing and sputtering. Nearest Grænihver is Bræðrahver, which is a broad, shallow pool with a small vent in the center. This feature frequently has a thin jet of water to about a meter. (It reminded me in appearance and eruption activity of #812 at Orakeikorako.)

Bræðrahver and Grænihver, Hveravellir

All these features have developed a wide sinter platform. In the middle of this is another spouter with a ragged crater surrounded by a yellowish-white sinter. To the side is a brown vent without activity, but with cauliflower formatins and beading as if it was active not long ago.

The lowest spouter, Nýihver, erupts to a height of about one meter, and is used as the hot water intake for the hot pool used for bathing. The water comes into the pool at around 180°F, and has to be mixed with cold water to make it useable, but there's still a thin layer on top (around 115°F) that requires hand mixing.

Nýihver (water intake), Hveravellir

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Observations for 2023 September 06


Got a late start to another busy day. Arrived at Haukadulur and parked in the northeast parking area, away from the tourist traps and bus parking areas. Almost immediately saw an eruption of Strokkur from our car. We got long series of eruptions, much on video.

A few years back I came across a recent paper published in Geophysical Research Letter titled "Eruption Interval Monitoring at Strokkur Geyser, Iceland". One of the most interesting pieces of information in it is that over the course of a year, their monitoring recorded 73466 eruptions, and that 23331 of those eruptions had more than one burst. There was even a single six burst eruption recorded. (Based on the statistical model, a seven burst eruption should also occur ever 12 years or so.) Also, the time between eruptions correlated to the number of bursts, but not to the number of bursts in a subsequent eruption.

We saw mostly one burst eruptions from Strokkur. There were a few with two bursts, with the second coming as soon as the first burst completed, to as much as 20 seconds later. (It's annoying when you stop the video only to miss the second burst becuase it took so long.) We only saw one three burst during the day, which based on the previously mentioned paper, was expected for the amount of time we were there.

Strokkur eruption. 2023-Sep-06:10:34, 2B. Video by H.Koenig.

The sizes of the eruptions varied considerably. Up close, some were just "tall." From a distance, I think we saw several that were over 30 meters high. On the otherhand, some were disappointingly small. In one case, I doubt the height was over 4 meters. Looked like a Grand Boop. When there were two bursts, one of the bursts could be tall, but not both, unless it was one of the cases when it was more like a second jet developing through the first jet.

Intervals ranged from two to seven minutes after a one burst eruption, but most of those were three minutes or less. If there was a second burst, then the interval lenghtened out to seven to ten minutes.

Geysir was quietly overflowing. What was surprising is that it is developing a shelf along the edge of the crater, and the overflow terrace has developed scallops well down the hillside.

Didn't see much else. Alfaauga was active, and we saw a few eruptions. The pool over the vent fluctuates until boiling starts on the side, which leads into an eruption. The durations were from over two minutes (it was in eruption) to a single burst. Didn't try to get any intervals, as it is located on the main path between the buildings and Strokkur, which is a crowded, busy area. (And Strokkur had our attention.)

Littli and Smiður were perpetually spouting to about a meter, and up at the top of the hill, Haìhver, while spouting continuously, did seem to vary from almost quiet to bursting well over a meter high.

We finally left after over five hours and 52 eruptions of Strokkur seen.

Arrived at Hveravellir about an hour and a half before it got dark, and after taking care of necessities like eating and checking in, had maybe half an hour of light to do a quick investigation. Nothing there erupts to much more than a meter, and the intervals are extremely short, but in that time saw close to two dozen eruptive vents and features, including at least three or four geysers. There was one feature erupting about every minute, draining after the eruption. The pool of Rauðihver would pulsate over the vent, then have a couple or so bursts. The tallest feature was a pool south from Öskurhóll, which was splashing almost two meters high at times. Should have plenty of time to investigate these further tomorrow.


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Observations for 2023 September 05


The first stop of the day was at Hveradalir, located to the north of Route 1 west of Hveragerði. This is an area of frying pans, mudpots and fumaroles with a walkway through it on the edge of a well developed geothermal powerplant.

The walkway crosses a lagoon, which the information sign says is artificial. After that, the next main attraction is a large mud pot upslope from the walkway which has built a several meter high cone,and was in the process of occasionally flinging mud onto the walkway. Beyond that is a powerful fumarole and an eruptive feature. The latter is active inside a stone and cement box with a hole in the side which allows water to escape the box. The fumarole is loud, and I couldn't see any actual steam coming from it, a sign that it is highly superheated. To get to the end of the walkway requires passing through the fumarole' steamcloud, a slightly scary experience.

Hveradalir mud pot
Hveradalir fumarole and box spouter

On the way back along the walkway, at the point where the walkway first crosses over the lagoon, we noted a small vent bubbling away. This activity was intermittent, and every minute or so it would increase to the point some splashes were getting to about 5cm high. Then the activity would cease for a few tens of seconds, only to start the cycle again.

The next stop was the Hveragerði Geothermal Park. I wasn't expecting much here as I knew about the changes after an earthquake 15 years ago when most of the pools empty and dried up. What I didn't expect was that there is an active, erupting feature there. It's probably artificial, and erupting borehole, but it is still a fascinating feature with a distinctive and unique eruption.

We saw four eruptions over about an hour period, the interval was about twenty minutes. There's just some rocks piled around the vent, probably the remnants of a borehole, and there is splashing about 1/2 meter high begins about five minutes after the eruption. This activity gets a bit stronger over then next fifteen minutes, but not by much. Suddenly, one of the splashes triggers an eruption, which lasts at most five seconds. There is a roar as water is expelled up to ten meters high, and just as suddenly drops down to nothing. According to the little map we got at the entrance, this is Eilifur Goshver/Eternity Geyser.

There's a second active feature, a small pool which splashes away and is located next to the cafe/greenhouse entrance to the park. It looks like it's probably a natural feature, as I didn't seen any evidence of concrete or other building materials around it. When I recorded the last eruption we witnessed, I decided I wanted a distant shot, so was standing about 25 meters from the Eilifur with the small pool in the foreground. As the eruption started, the pool suddenly increased in activity and force and the splashing was well over a meter high for just as long as the eruption lasted. Then it reverted back to its previous splashing.

Eilifur Goshver/Eternity Geyser at Hveragerði Geothermal Park

The next stop was a thermal area up on the hillside north of town. Over about 100 meters is a line of mudpots and acidic springs. At the northern end are signs with names for some of the features: Reykjamóri, Leirgerður and Skjálfti. Based on these, I think it was Skjálfti that was having eruptive episodes. This feature contained opaque, brownish red water which was boiling up and splashing from every locations. Every minute or two the activity would get stronger in one of the vents, and the splashing would be one or two meters high.

Skjálfti north of Hveragerði

The final stop of the day was to see Littli Geyser at Gamla Laugin/Secret Lagoon in Fluðir. It, along with several other boiling springs, are on the grounds of the spa and provide some of the waters used.

The vent is maybe 25 cm across, and there are two deeply incised runoff channels leading from it. Most of the time there is water flowing down one of these channels, and the vent is in a constant agitation to maybe 25cm high.

Based on an hour and a half's observations, Little has three sizes of eruptions. The minor is shorter and not as tall, and the vent almost immediately resumes overflow and splashing. The larger eruption lasts longer, is taller and the vent drops below overflow and refills over about a minute. The major eruption is the tallest and longest, with some of the eruption getting to about four meters high. After the eruption the vent drains with the usual array of sounds.

All but one series consisted of two minor eruptions about two minutes apart, and then two minutes after that, a major eruption. It takes about five minutes between a major and the next minor. The time we saw the intermediate eruption, it was after the first minor eruption, and it was followed by another minor and then a major.

Littli Geysir at Gamla Laugin/Secret Lagoon in Fluðir

Near Litli are some deep boiling springs. One had collapsing bubbles at the bottom, maybe 1/2 meter below the surface. There's also another boiling spring, Vaðmálahver between the spa and the Litlà-Laxa River.


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Observations for 2023 September 04


Visited our first Iceland thermal features today. Gunnuhver sits in the middle of a production geothermal field. The activity consists of a perpetual spouter which has jets of water up to 8 meters high. The vent is obscured by the remnants of a boardwalk which it destroyed earlier this century.

Nearby is a large mound of siliceous sinter. It's old and heavily eroded, but there are still rock fragments featuring flow patterns and terracettes.

To the west of the recent volcanic activity is Seltún, south of Kleifarvatn. There's a large parking lot along with plumbing facilities which may or may not be open.

Next to the parking lot is a large muddy spring which was erupting gray water to about 1/2 meter. A boardwalk trail continues up the hillside past more large acid sulphate springs and numerous small spouters.

Across the road is another small thermal area consisting of two large mudpot craters. They were more of a pool than a mudpot, probably thanks to the heavy rains in the couple of days prior to our visit.

Behind the plumbing facilites is an old geothermal well. When I first looked at it, there was occasional noise coming from below ground as it there was some sort of eruption going on. About twenty minutes later, I stopped by again and the feature was quiet.


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Observations for 2023 August 30


Made the mistake of assuming that since Grand had a short interval while Rift was erupting, the next interval wouldn't be too bad. Add in the fact that the moon was nearly full.

A minor storm came through just after dark, and while there wasn't much rain, it brought a steady wind. For the first hour or so, the moon was mostly hidden by the clouds, but then the sky cleared. Because of the wind, and despite the bright moonlight, very little steam was visible from Grand and Turban, which made it difficult to guage the status of Grand's pool.

Three hours and ten short, weak Turban eruptions after arriving we finally got a Turban Delay overflow. Since Grand didn't erupt, that meant it would probably be at least two Turban eruption intervals and 45 minutes before the Grand eruption, so we went back in. As it turned out, it appears there were probably four Turban eruptions, as Grand didn't erupt until 1-1/2 hours later.

2023-Aug-29 
23:39:58			d=3m31s 	
23:57:58	Int: 18m00s	d=3m38s 	
2023-Aug-30 
00:15:32	Int: 17m34s	d=3m02s 	
00:32:12	Int: 16m40s	d=3m11s 	
00:52:34	Int: 20m22s	d=3m24s 	
01:10:39	Int: 18m05s	d=3m03s 	
01:28:19	Int: 17m40s	d=3m28s 	
01:47:49	Int: 19m30s	d=3m20s 	
02:04:44	Int: 16m55s	d=3m19s 	
02:36:25	Int: 31m41s	d=4m18s  D0	

Getting a Beehive eruption at sunrise was a minor consolation. The long Indicator eruption gave people plenty of time to get into position. It was still windy, and the wind shifted enough to make the few people there move back.


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Observations for 2023 August 29


August weather finally arrived today, with a clear morning that warmed quickly. Out at Grand there was an eruption of Oblong shortly after I arrived. Only waited two Turban eruption intervals (with a Daisy eruption during the second). But that last interval was a Turban Delay Interval lasting almost 35 minutes. Grand's pool did not look good when Turban started, but we ended up with a One Burst Grand Eruption (nicely backlit) about 80 seconds later.

2023-Aug-29:10:14:34 D0/T1Q

10:13:15	Turban		-1m19s
10:14:34	Grand B1	---	d=11m31s
10:17:01	Vent		2m27s
10:21:52	FP		7m18s
10:26:05	P1		11m31s
10:26:53	V&T Quit	12m19s

				     	ΣD=11m31s
	* * * * *
09:24:57			
09:39:23	Int: 14m26s	d=4m38s 	
		     Turban: 33m52s

To enjoy the good weather, went out and spent some time at Grotto, which was not close to erupting, then caught a Daisy eruption. By that time, Rift was in eruption, which of course disrupted some plans for the rest of the day. Shortly afterwards, Castle started, and since there had been a minor in the morning, decided that a major eruption was most likely, so went there to watch the transition into steam. It was way too early for rainbows.

With Rift erupting, I decided there wasn't a good reason to be out early for the Grand eruption. So I missed the One Burst Grand that appears to have happened during the Rift eruption.

Another reason to skip Grand was that I had been invited to go to the roof of the Inn, and didn't want to have to abandon Grand. The weather conditions were ideal, but unfortunately, nothing much was erupting. Did see Little Squirt, Little Cub and White from up there.

During that time, the bellman/guide mentioned a mudpot making loud thumping noises. Based upon what he said, we eventually found it just south of the High Bridge where the road to Craig Pass crosses the river. The route to it starts at the Mallard Lake Trailhead. Don't cross the bridge, but head right/west toward the employee fire-ring. As we approached there, we heard a low thumping off in the distance. We followed the sounds and eventually arrived at the mudpot, on the cabin side of the river, on the hillside below the old campground. There are several pools in the mud volcano, all at different levels and liquidity. The one making the noise was the deepest, and no water was visible, just noise and steam.


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Observations for 2023 August 28


Was bicycling past the Inn when I noticed there was a lot of steam around Beehive. At first I thought I'd missed the call for the Indicator, but then Beehive started along with an announcement of "no Indicator". So Beehive must've had some huge splashes. Watched the eruption for a bit, then went on to tie up my bike at Castle. Walked out toward Crested, and Beehive was still in eruption, almost six minutes later.

Over at Grand it seemed like I walked up on a Turban Delay Interval, and the following Turban eruption without any Grand overflow seemed to confirm this. The Delay took place well before I'd expected Grand, so I hoped that it meant we'd have only a few Turban eruptions to wait out before getting a relatively short Grand interval.

2023-Aug-28:15:11:28 T1Q

15:10:49	Turban		-0m18s
15:10:53	Vent Ovfl	-0m14s
15:11:08	Grand B1	---	d=10m41s
15:13:30	Vent		2m22s
15:21:49	P1		10m41s
15:22:45	V&T Quit	11m37s

				     	ΣD=10m41s
	* * * * *
11:58:08			d=5m18s 	
12:16:05	Int: 17m57s	d=4m51s 	
12:35:02	Int: 18m57s	d=4m29s 	
12:54:53	Int: 19m51s	d=3m11s 	
13:10:34	Int: 15m41s	d=3m54s 	
13:29:26	Int: 18m52s	d=3m58s 	
13:47:17	Int: 17m50s	d=3m38s 
14:02:49	Int: 15m32s	d=3m40s 
14:21:33	Int: 18m44s	d=3m43s 
14:39:31	Int: 17m57s	d=3m25s 
14:55:40	Int: 16m08s	d=3m31s 
		     Turban: 15m09s

As it turned out, it took Grand 11 Turban eruptions before we got the One Burst Eruption.

The after sunset wait was much better, as there seemed to be no Turban Delay Interval this time, and the One Burst Grand Eruption started near the 6-1/2 hour mark. The conditions were ideal for a nearly full moon eruption, with the usual down slope wind pushing the steam toward the north. But no moonbows this night. And despite the early prediction window, only geyser gazers were present.

2023-Aug-28:21:41:15 T1C

21:41:08	Turban		-0m06s
21:41:15	Grand B1	---	d=10m26s
21:51:41	P1		10m26s
Vent & Turban continue

				     	ΣD=10m26s
	* * * * *
21:01:02			d=4m51s 	
21:20:26	Int: 19m24s	d=4m27s 	
		     Turban: 20m42s

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Observations for 2023 August 27


It was foggy in the Lower Geyser Basin, and we arrived by bicycle at Great Fountain while it was in eruption, probably the third series of bursts. Knowing the time of an eruption, decided to attempt to see the next eruption that evening.

In the afternoon, went out ot Grand as the weather was getting worse. Fortunately, and despite a long Turban Delay Interval, got to see the One Burst Grand eruption before the rain.

2023-Aug-27:16:21:21 D0/T1Q

16:20:36	Turban		-0m45s
16:21:14	Boop		-0m07s
16:21:21	Grand B1	---	d=11m23s
16:22:34	Vent Ovfl	1m12s
16:23:45	Vent		2m23s
16:32:44	P1		11m23s
16:33:39	V&T Quit	12m17s

				     	ΣD=11m23s
	* * * * *
15:45:43			d=4m33s 	
		     Turban: 34m52s

The forecast storm never really materialized, so by 19:00, went back to Great Fountain. Arrived to find the water level in the crater out of sight. Over the next hour, as the sun set, the water level would come into sight, only to sink again. After sunset, the overflow had not yet started, so we decided to head back instead of waiting at least another 1-1/2 hours.

The sky had cleared by the time Grand was due to erupt. Waited for an hour's worth of Turban eruptions, then got the One Burst Grand eruption that lasted less than ten minutes. But as we were crossing the bridge, Castle started erupting. For once, a Castle eruption with the moon in the proper location resulted in a major eruption with full arc moonbows starting about the time the eruption turned into steam.

2023-Aug-27:23:17:28 T1C

Yesterday 23:16:43	Turban		-0m45s
Yesterday 23:17:28	Grand B1	---	d=9m52s
Yesterday 23:27:20	P1		9m52s
Vent & Turban continue

				     	ΣD=9m52s
	* * * * *
Yesterday 22:04:41			
Yesterday 22:20:22	Int: 15m41s	d=4m37s 	
Yesterday 22:39:59	Int: 19m37s	d=4m27s 	
Yesterday 22:57:34	Int: 17m35s	d=4m20s 	
		     Turban: 19m09s

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Observations for 2023 August 26


Wanted to go out to Grand last night, but rain started just about the time to head out. Looking at the weather maps, it looked like it wouldn't clear before the moon set, so stayed in.

That rain made it extemely humid, and there was a thick fog in the morning. It didn't help that at the time I didn't know when the previous Grand eruption had happened. Turned out I probably saw the first Turban eruption after Grand's first overflow. So ended up waiting two hours. After that, it was still fogged in, and dead calm when we got the One Burst Grand eruption. Afterwards, as I biked back in, the fog was starting to break at the south end of the basin.

2023-Aug-26:08:33:32 T1C

08:33:22	Turban		-0m10s
08:33:32	Grand B1	---	d=9m25s
08:36:09	Vent		2m36s
08:42:58	P1		9m25s
Vent & Turban continue

				     	ΣD=9m25s
	* * * * *
06:22:43			d=2m04s 	
06:43:06	Int: 20m23s	d=4m57s 	
07:03:05	Int: 19m59s	d=3m54s 	
07:21:39	Int: 18m34s	d=3m54s 	
07:38:22	Int: 16m43s	d=4m09s 	
07:57:21	Int: 18m59s	d=3m29s 	
08:14:17	Int: 16m56s	d=3m47s 
		     Turban: 19m04s

Was still not totally clear when Beehive erupted, but because it was calm, the water column was straight up, and only a portion of the walkway got wet.

There was another event at Fan & Mortar. As in the previous cases, Bottom Vent had a strong eruption, Main Vent was splashing, and Lower Mortar was also high. But while Fan's vents started strong, after a couple of minutes they'd died down well before Angle started.

The midday Grand eruption was a bit of a fiasco. I went out early because I had not much else to do. Almost immediately I caught a Turban eruption, one which lasted almost six minutes. That's usually the sign of a Turban Delay Interval, and when the next Turban interval had little Grand overflow, I was pretty sure of that.

Around the time of the second Turban eruption after that, I looked at a weather map and saw that there was a pretty strong thunderstorm headed our way. That's when the NPS radio had a severe weather alert, with one inch hail and 40 mph winds headed our way. Normally,with less information and with the way the sky looked, I'd have just hunkered down and waited the weather out. But the "one inch hail" part was enough to make me decide to clear out. I got into the trees between Liberty and Lion when the hail started, and decided that was a better place to experience hail than Geyser Hill. Turns out less than ten minutes later, the sky was clearing and the rain was mostly over. So much for the "severe weather."

I headed back to Grand, and arrived at about 22 minutes after the previous Turban eruption start. Grand was obviously in heavy overflow, and having another Turban Delay interval. Most of the people who had been waiting for Grand, gazers and tourists, had cleared out. At exactly 25 minutes, Turban started, followed almost immediately by the One Burst Grand Eruption.

2023-Aug-26:15:00:08 D3/D0/T1Q

15:00:05	Turban		-0m03
15:00:08	Grand B1	---	d=10m20s
15:00:10	Vent Ovfl	0m02s
15:03:01	Vent		2m53s
15:10:28	P1		10m20s
15:11:59	V&T Quit	11m51s

				     	ΣD=10m20s
	* * * * *
13:56:17			d=5m44s 	
14:14:21	Int: 18m04s	d=4m22s 	
14:35:05	Int: 20m44s	
		     Turban: 25m00s

There were clouds obscuring the moon as we went out to Grand. Once again, I saw what appeared to be a Turban Delay interval when I arrived. Fortunately, Grand erupted just two Turban eruptions later. Not only did we get a second burst after a fairly long first burst, but the moon was shining through a clear spot in the clouds.

2023-Aug-26:21:11:25 D2/T2Q

21:11:03	Turban		-0m22s
21:11:25	Grand B1	---	d=9m07s
21:20:32	P1		9m07s	d=0m48s
21:21:20	B2		9m55s	d=0m48s
21:22:08	P2		10m43s
21:23:07	V&T Quit	11m42s

				     ΣB=9m55s	ΣD=10m43s
	* * * * *
20:31:16			
20:49:36	Int: 18m20s	d=4m45s 	
		     Turban: 21m27s