This Earth Cache will show you the Berca mud volcanoes. Several sites with mud volcanoes are known in Romania, with those here in the Berca-Arbanasc valley being the largest . An area of 30 km2 surrounding the Berca mud volcanoes was declared a nature reserve in 1924. Here, two sites exist in close proximity, Paclele Mari (above coordinates) and Paclele Mici (N 45° 20.350 E 026° 42.500).
The mud volcanoes are formed by "eruptions" of natural gases - primarily methane - that cause mud, underground water and sometimes oil to be pushed to the surface, where the mud dries and formes volcano-like structures many metres high . It is estimated  that the Berca mud volcanoes emit about 1200 metric tonnes of methane per year, a potent greenhouse gas. The gas is emitted from a depth of ca. 3 km.
Geologically, two types of mud volcanoes can be distinguished. One type is associated with true volcanic activity, the other type is not . The Berca mud volcanoes belong to the latter type. Mud volcanoes are often associated with either geodynamically active regions or the presence of oil and gas deposits , or both as is the case here.
In order to log this cache, please answer the questions below and send them to the e-mail adress in our profile:
1) Is the mud ejected from the volcanoes hot or cold, and why?
2) How many active "craters" can you identify?
3) Estimate the approximate height of the highest mud volcano - there is no need to be precise here, just make a guess.
4) Do you think the answers to (2) and (3) will be the same if you come back in a year or so, and why?
5) (optional) Upload a picture of yourself and/or your GPS with your log
You can log the cache as soon as you have sent the answers, there is no need to wait for a log permission. If there are any problems with your answers we will get in touch ...
 V.N. Kholodov, Lithology and Mineral Resources 37(2002)197; Mud Volcanoes, Their Distribution Regularities and Genesis: 1.
 Wikipedia - Berca Mud Volcanoes
 G. Etiope et al., Terra Nova 16(2004)179; Gas Flux to the Atmosphere from Mud Volcanoes in Eastern Romania
Photos & video: own work; flags: public domain