Apple #639: Geothermal Mud Pots

I'm starting with a preamble.  If you want to, you can skip it and go straight to the geothermal mud pots (a.k.a. the good stuff).


Geothermal mud pot at Yellowstone.
(Photo by Christian Begeman)

Coughing in the Middle of the Night & Being Speedy

For the past several nights, I've been waking up in the middle of the night coughing.  It's been driving me nuts.  I Googled the problem, and it turns out this is pretty common.

(Side note: I didn't want to do a Daily Apple on this because I've learned the hard way that medical problems can have so many possible causes, the entry very quickly becomes less than useful, and then people post questions about their own medical situation, and not being a doctor, I have no business giving advice even if I knew what to say.)

But based on what I read (the best source I found on the subject is Harvard Medical School's page), and based on my personal situation, my coughing is probably due to the most unpleasantly phrased post-nasal drip.  The liquid from the nose slides down to the throat while you're asleep and triggers a cough.

I've so far tried various home remedies: sleeping on a propped up pillow, a tablespoon of honey before bed, gargling with saltwater, using a Neti pot.  In spite of all these things, I still wake up coughing.  So now I'm trying another suggestion, which is a nasal decongestant.  I hate these things because whether they say non-drowsy or may make you drowsy or whatever, they make me so speedy I can't sit still.  I've only tried one or two of these types of things in my life and I can't remember which ones I've tried, so I picked one off the shelf pretty much at random, and now here I am all twitchy and itchy and speedy from the stupid stuff.  What's more, I still keep having to blow my nose.

So it's probably going to be a long night.

And I'm probably going to be extra-wordy in this entry.  You've been warned.

Geothermal Mud Pots

Mud pots in action near Calipatria, CA.
(Photo from flickriver)


I was trying to decide on a topic for this week's Daily Apple.  Naturally, I thought some type of natural disaster might make a good post.  I've covered hurricanes, earthquakes & tsunamis, thunderstorms, and derechos, and while I haven't done an entry on volcanoes in general, I did do one on Mount Etna.  I have not done an entry on tornadoes, but I did sort of mention them in last week's entry on why Oklahoma has no basements despite being practically a magnet for tornadoes. So I thought something other than tornadoes would make a nice change.

So I cast my mind back to junior high science classes and the movies the teachers used to show us about natural disasters and earth science.  Earthquakes, volcanoes, etc.  The volcanoes were my favorite part, but another really good part was about the geothermal mud pots.  Everyone in the class got a huge laugh out of seeing those things spew mud and make all sorts of rude noises.  Then we'd beg the teacher to please please please run the film backwards (you kids with your DVDs and your VCRs will never know such delights), and if he was in a good enough mood, the teacher would do it.  Oh, the hilarity.

OK, so let me show you some videos of these geothermal mud pots, and then I'll find out some facts about them and pass those facts along to you.

This one is from Kamchatka, Russia.  The sounds still make me giggle.  Completely juvenile humor, I know.




Here are some closer to home in Salton Sea, California:




This one shows the mud pots across a whole area:




Now for the facts, ma'am.

• Mudpots are one kind of geothermal activity. Hot springs and geysers are similar, but they each have slightly different characteristics.

• Here's how geothermal stuff happens:

• Beneath the crust is a layer of magma, or hot molten rock.  The movement of the plates that form the earth's crust or volcanoes can force the magma closer to the crust.  

• If the magma shoots up through the crust, you get volcanoes.  When groundwater comes in contact with the magma and the resulting steam shoots up, then you get geothermal activity.

• Hot springs happen when the steamy water coming up from below forms a pool. Usually the water contains various minerals that come from the magma.  Hot springs are usually not that hot but only warm, so sometimes people like to bathe in them.

• If the water doesn't stay in a nice calm pool but shoots up like a fountain, then it's a geyser.  A whole lot of pressure is required to make the steam shoot up like that, so usually there's a huge underground network of twisting and turning tunnels that hold the groundwater and keep the pressure building until finally the thing spouts off.

(Encyclopedia Britannica has a really great diagram that illustrates this whole process for hot springs and geysers. I can't embed the link here for copyright reasons, but it's worth the click to see it.)

• Mud pots are similar to hot springs in some ways.  Usually the steam coming up isn't jet-propelled like a geyser but only bubbling to the surface.  It's often not super-hot but only warm.  Mud pots may also form pools, as hot springs do.  But there are two major differences.  

• In mud pots, the steam coming up from below also contains sulfuric acids that erode the surrounding rock.  The rock turns to sand and clay and that mixes with the water, making mud.  

• The sulfuric acid also means that most mud pots have a definite odor about them, like the smell of rotten eggs.

• The material surrounding the mud pots often also includes volcanic ash, or rocks that have been formed from volcanic ash (i.e. pumice).  When water interacts with the ash, or when the acidic water hits the pumice, it makes bubbles.  When the bubbles rise to the surface, they burst and fling the mud in all directions.

 I know you want to see more.

• Mud pots can change  in character as the amount of water varies.  If there's a lot of groundwater, the water can overwhelm the mud and it becomes more like a hot spring.  If there's too little water, the mud pot will dry out and it becomes only dry, cracked earth with steam venting from it.

• Mud pots can also turn into what people call mud volcanoes, or mud domes, or mud gryphons (< 3 meters tall).  The mud can pile up around the opening of the mud pot, getting taller and taller while the muddy steam still keeps spewing out.

• The steam coming up from the volcanoes is often hotter than what's in the mud pots

 
Mud volcano, or mud gryphon, at Salton Sea
(Photo from Toadhaven Home School)


Video of a mud volcano in action, followed by some dry mud pots issuing steam. Please also enjoy the videographer's Midwestern accent.

• A geothermal power plant has been built near these mud pots at Salton Sea, and some people say the mud pots are no longer as active or fun to watch.

• Some mud pots also have other minerals such as iron oxide, potassium, or magnesium which give the mud color.  Those mud pots are typically called paint pots.  Paint pots have no sulfur.  If they did, the sulfur would turn the mud gray.

In part of this video, the mud is pink. That's a paint pot.





An especially vibrant paint pot at Yellowstone.
(Photo from Globus Journeys)

• All these mud pots will vary from one season to another, and from one year to the next.  Over time, they may change a lot, even dry up completely.  Some people say the mud pots at Yellowstone don't look anything like they used to.  A geothermal power plant was built near the Salton Sea mud pots to harvest some of the geothermal steam coming up in that area.  As a result, the mud pots there are reportedly nowhere near as active now as they are in the videos shown here.

• But there are mud pots in lots of places in the world.  There are some in New Zealand, some in Iceland, and some in Costa Rica.  Who knows, some others may pop out in new places, too.

Mud pot in Iceland, and some steam vents. (This video is pretty loud.)





Sources
Home Science Tools, Geysers
Janice Kleinschmidt, Sea of Wonders, Palm Springs Life, March 2006
Geothermal Features, Mud Pots
National Park Service, Yellowstone, Mudpots and How They Work