My family owns a perfect piece of nasty swamp. It started its days as a mountain lake that probably contained trout and other nice things, but over the years it silted up and it slowly turned into a swamp. Some twenty years ago it was totally covered up with peat and turned into a rather nice ground to pick cloudberries.
Five years ago a rockslide fell into one of the sides of the swamp and a couple of days later a thunderstorm struck the area. Que me on a cloudberry picking round, as I came there I noticed a heat shimmer out near the middle of the swamp. As I gingerly picked my way further out I found a 1.5 meter high sputtering flame coming out of the swamp.
What has happened was not so hard to deduce really. As the rockslide hit the swamp it increased the load on the top and trapped gasses was pushed towards the softer middle where it started to gush up. The gasses form as plant material decomposes in the oxygen free environment. The decomposition is slow since it is caused by anaerobic sulphur bacteria. If you apply pressure and time to such a place you get coal or oil. In this case a lot of methane had been produced, and that was what was burning. After a year the pressure was lowered enough for the flame to go out, instead a spluttering hole formed filled with bubbly mud water interspersed with half rotten plant material.
This has of course sparked my interest in odd boggy features of bubbly nature.
Fiumicino mud geyser
On the 23rd of August a hole opened in the ground in a turnabout next to the airport of Rome situated in the ancient roman port city of Fiumicino. Back in the day this was where the mighty roman eastern fleet was gathered, and where all goods travelling by sea to Rome was offloaded.
One can still see the spectacular roman fortified fleet harbor in the form a of a hexagonal lake called Lago Traiano, back then it was known as Porto Traiano (Port of Traianus). Another feature is quite dominant in Fiumicino and that is the river Tiber. During the time it served both as a water way to Rome, and as the main means of garbage disposal. It was back then so disgusting when it left Rome that a standard roman joke was that you could walk dry footed across the river as it left the city. The truth was probably not that far off.
As the old port Ostia Antica became to silted up Emperor Traianus decided to build the new port, as they did that they dug a new canal that connected the Tiber to the ocean. The canal was built through an old swamp land created by the river as it moved around creating an ancient delta.
The Tiber has created an area filled with mud and decomposing material, this in turned into a swamp, then a canal was dug that further filled up the area with decomposing material. And as the modern man needed an airport the entire area was further filled up with landfill (garbage) creating a perfect breeding ground for anaerobic sulphuric bacteria.
As the mud geyser came to life it was believed that it might have been volcanic in nature. In reality the closest volcanic field is more than 50 kilometers away at the Alban Hills, and there is nothing pointing towards the area having been geologically active in a truly long time.
In theory there could have been volcanic activity under Fiumicino more than a million years ago, and in theory the gasses could come from an ancient gas pocket. But the nature of the gasses, CO2, methane and H2S (hydrogen sulphide) points away from volcanic origin (but does not prove it so).
Most likely the Fiumicino mud geyser has formed from rotting plant material, roman corpses, roman feces, and other assorted roman nasty things. And as the landfill was laid on top the pressure in the end became high enough to start squeezing up gasses and sulfide mud (the gray material).
To me this is a miracle of the ancient world, not a volcanic feature.
Video showing an early stage of the mudcano:
Newest video of the mudcano showing how it is slowly evolving:
In a rather unlcear bulletin INGV has declared that it is a Mud Volcano. They do point to it being in an area where volcanism exist, but do not point to a certain volcanic origin. The volcanic area they point to is Monti Sabatini, and not Fiumicino and the area north west of Lago Traiano. Monti Sabatini is of volcanic origin, and the area now is not of certain volcanic area. I fear we are as much in confusion after this bulletin and have to wait for hard scientific data.
I would also like to clearify that this post is giving my opinion of what I think is the most likely cause of the Mud Volcano. If new data comes to light I will post a new post.