geographia - Studia

ANDREA GÁL
The main purpose of this study is to present a new typology from the point of view
of the morphology and internal structure of mud volcanoes from the studied area. As a starting
point, Bányai’s classification (1932) was used, which takes into account the morphology and
some (supposed) internal aspects of mud volcanoes distinguishing four types: “bottomless mud
pits” (selymék), “maybug” (bogárhátas), “stack” (boglya), “white mud mounds” (fehérszék).
32
2. METHODS AND CRITERIA OF THE CLASSIFICATION
The studied mud volcanoes have been analyzed directly on the field from the point
of view of morphology, morphometry, evolution (in cases when they have been observed
several times) and the characteristics of the discharged material. The manual shallow
drillings provided not only the samples but useful information regarding the internal
structure. Using this information, the drilling profiles have been drawn up leading to the
establishment of a new classification.
The following criteria have been taken into consideration in the new typology:
external morphology, morphometric elements, internal structure, intensity of activity,
characteristics of the discharged material, the presence of vegetation (total, partial and lack
of vegetation) and if the mud volcano has appeared on a flat or sloping surface.
As far as the surface morphology is concerned, the shape of the mud volcanoes has
been analyzed: flat, cone, truncated cone, dome, and the curve which describes the best the
respective form. The outline curves have been drawn on the basis of the photographs and
the morphometric information. Regarding the subsurface morphology, the form and
dimensions of the feeding channel and the presence or lack of near-surface mud chambers
have been examined.
Five intensity levels have been defined: 1. active mud discharge and/or bubbling
of gas, 2. fresh mud without active discharge (in the case of positive shapes) and bubbling
mud not covered by vegetation (in the case of negative forms) 3. mud volcanoes covered by
vegetation which can be reactivated if the vegetation which blocks the vent is removed 4.
covered by vegetation which can’t be reactivated, but quakes under one’s feet 5. inactive,
with no signs of activity, only the shape or the references in bibliography alludes to the
existence of a mud volcano.
3. CLASSIFICATION OF MUD VOLCANOES
After studying all the 60 mud volcanic features, despite of the diversity in surface
expressions (shape and activity), some characteristic features have been recognized in
morphology and evolution which allow us to establish a new classification. We propose to
separate four types: gryphon, mud mound, mud crater and mud pool.
3. 1. Gryphon
The term gryphon has been defined by Kopf (2002) as a small cone (up to 3 m) off the
crest or on the flank of a large mud volcano. In this study the term gryphon is used in a similar
meaning, with the difference that it will not denote a secondary feature (the ramification of
the main conduit) but the mud volcano itself.
Gryphons are represented by those positive mud volcanic features which result
from the deposition of mudflows extruded through a narrow feeder channel on the preexisting
topographic surface. The gryphon is built predominantly by the addition of material to the