At https://tallbloke.wordpress.com/2017/07/19/ten-year-old-mud-volcano-baff… … (see also http://en.wikipedia.org/wiki/Sidoarjo_mud_flow ) which tells you all you need to know about the biggest known mud volcano in the world, close by Sidoarjo in Java. It erupted eleven years ago and has not stopped since then. At its peak it disgorged 180,000 cubic metres of mud every day, buring villages under mud up to 40m thick. Oldbrew says mud volcanoes are not true igneous volcanoes as they don't produce lava but it seem the Earth continuously exudes a mud like substance which sometimes is described as a mud volcano. Smaller mud exudations are sometimes referred to as mud pots.
Over at https://phys.org/print419265348.html … a paper published in Science Advances (July 14th 2017) suggests that many of the original planetary building blocks in our solar system may actually have started out not as rocky materials that went on to accrete into bigger bodies but as gigantic balls of warm mud. The piece ends by saying the findings provide a new scientific approach for research into the evolution of water and organic material in the solar system.
However, see also https://tallbloke.wordpress.com/2017/07/19/earths-water-explained-by-gas… …where water on Earth and anywhere else in the inner solar system was caused by waist expanding growth of Jupiter and Saturn, gobbling up a local population of icy planetesimals. Clearly, the origin of water is taxing some brains.