San Jacinto Fumaroles and Mudpots
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On the southeast flank of 1061-m (3481 foot) Volcan Telica, Los Hervideros de San Jacinto, are a nest of boiling mudpots and thermal vents (fumaroles) fueled by the underground geothermal activity.
Mud Pots
A mudpot, mud pool or paint pot is a sort of hot spring or fumarole consisting of a pool of usually bubbling mud. Mudpots form in high-temperature geothermal areas where water is in short supply. The little water that is available rises to the surface at a spot where the soil is rich in volcanic ash, clay and other fine particulates. The color and viscosity (thickness) of the mud changes along with seasonal changes in the water table, and varies between adjacent mu pots.
The mud takes the form of a viscous, often bubbling, slurry. As the boiling mud is often squirted over the brims of the mudpot, a sort of mini-volcano of mud starts to build up, sometimes reaching heights of a meter (3 feet) or more. Although mudpots are often called “mud volcanoes”, true mud volcanoes are very different in nature (see below).
Generically, the mud of mudpots is generally of white to grayish color, but may be stained with reddish or pink spots from iron compounds, or other colors depending on the composition of the surrounding soil. When the slurry is particularly colorful, the feature is then referred to as a “paint pot”. The San Jacinto mudpots differ in size and color, varying from grey to black to red. Every year more mudpots form in the area, and existing pots change with the wet and dry seasons.
These features are caused by geothermal activity beneath the area. The mud and gases are very hot. The bubbles coming out of the mud are the result of both boiling and gases escaping up from deep in the earth. These gases are generated by hydrolysis, or the chemical decomposition of a compound into other compounds by reacting with water. This reaction is accelerated by the heat of the underlying magma. As you approach the mudpots you can often hear the gurgling and sputtering of gas coming out of the mud. Take extreme care, as the mud sometimes throws little rocks into the air and steam is continuously emitted from the holes.
Fumaroles
Fumaroles are openings in the Earth’s crust, often in the neighborhood of volcanoes like Telica, which emit steam and gases such as carbon dioxide, sulfur dioxide, hydrochloric acid and hydrogen sulfide. The name solfatara is given to fumaroles that emit sulfurous gases, like at San Jacinto. Use extreme caution, as these escaping gases may make breathing difficult. From the perspective of groundwater, fumaroles could be described as a hot spring that boils off all its water before the water reaches the surface. They may occur along tiny cracks or long fissures, in chaotic clusters or fields (as at San Jacinto), and on the surfaces of lava flows and thick deposits of pyroclastic flows.
Mud Volcanoes
Mud volcanoes or mud domes refer to formations created by geologically excreted liquids and gases, although there are several different processes which may cause such activity. Temperatures are much cooler than igneous processes, and most of the released gases are methane, with much less carbon dioxide and nitrogen emitted. Mud volcanoes are often associated with petroleum deposits and tectonic subduction zones and orogenic belts; hydrocarbon gases are often erupted. They are also often associated with lava volcanoes; in the case of such close proximity, mud volcanoes emit incombustible gases, whereas lone mud volcanoes are more likely to emit methane. Most liquid and solid material is released during eruptions, but various seeps occur during dormant periods
Because mud volcanoes are frequently associated with earthquake zones, many scientists suggest monitoring their gas emissions and activity because they can be suitable to predict strong earthquakes.
Mudpots, fumaroles and mud volcanoes are often found together. The most notable and well-visited area is Yellowstone National Park in the USA.
San Jacinto Thermal Field
The field is not big but is interesting as well as extremely hot to walk around and see the holes. There is a good variety of mudpot sizes and colors. Many local kids will offer to guide you around for a peso or two, and this is highly recommended because there are no clearly set paths that mark where it’s safe to walk. There are parts where it’s not safe to walk because of a weak soil, and the kids know where. As mentioned above, be cautious of ejected stones and noxious gasses. There is a $2.00 US admission, with daily openings between 0700 to 1700 hours.
To claim this EarthCache
1. Take and post a picture of you and your GPSr at one of the mudpots and e-mail me the answers to the following questions:
2. What is the dominant color of the mud in the mudpot in your photo and what is/are the likely chemical(s) contributing to the color?
3. What is the likely chemical of the distinctive smelling gas coming from the mud pots and fumaroles?
4. San Jacinto mudpots and fumaroles owe their geothermal activity to Volcan Telica. What type of volcano is Telica, and how many craters does it have?
Do not post your answers, encrypted or otherwise, in your log.
DO NOT LOG AS A FIND UNTIL YOU HAVE A PICTURE READY TO POST AT THE TIME OF LOGGING A FIND FOR THIS EC. Logs with no photo of the actual cacher logging the find or failure to answer required questions through e-mail will result in a log deletion without notice. Exceptions will be considered if you contact me first.
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