4. RESULTS AND DISCUSSION
4.1 The Abstract Area
Visual analysis of the maps obtained (Fig. 1) confirms that
the theoretical basis of the method is mostly correct. After
dip-slip faults modelling (Fig. 1 d) clear lineament passing
strictly along fault axes is recorded on Kv map (Fig. 1 f).
Some vertical motion traces are revealed by Kh mapping
too (Fig. 1 e) but there are no lineament along fault axes.
After the strike-slip fault modelling (Fig. 1 g) only Kh
mapping allows us to reveal a small lineament in the
lower part of the map (Fig. 1 h). This lineament passes
strictly along the dislocation axis. The Kv map does not
contain lineaments (Fig. 1 i) although strike-slip fault
traces are revealed which are a break of the valley and a
displacement of its east part northward.
After the oblique-slip fault modelling (Fig. 1 j) the clear
expressed lineament, the break of the valley and the
displacement of its east part northward are revealed on the
Kv map (Fig. 1 1). Vertical and horizontal motion traces
are recorded by Kh mapping (Fig. 1 k) but there is no
theoretically presumed lineament along the fault axis. This
fact contradicts the theoretical basis of the method and, in
principle, can be connected with drawbacks of the oblique-
slip fault modelling. Besides, we may probably suppose a
lesser "sensitivity" of Kh to horizontal tectonic motions
(Fig. 1 h, k) as compared with Kv "sensitivity" to vertical
movements (Fig. 1 f, 1). However, real DEMs processing
demonstrates that both Kh and Kv mapping allow us to
reveal lineaments with equal "sensitivity" level (Florinsky,
1992). Probably, this may be a result of erosion influence
which can increase topographic expression of faults, for
instance, in forms of fault-line valleys or scarps.
After thrusts modelling (Fig. 1 m) clear lineaments
passing along fault axes are revealed by Kv mapping (Fig.
1 o). Some overthrust traces are also recorded on Kh
maps (Fig. 1 n) but there are no lineaments along fault
axes.
After the gaping fault modelling (Fig. 1 p) the clear
lineament is recorded on the Kh map (Fig. 1 q) as well as
the lineament broken by the valley is revealed by Kv
mapping (Fig. 1 r).
4.2 The Part of the Crimean Peninsula and the
Adjacent Sea Bottom !
Kh mapping allow us to reveal a) a complex of near-north
oriented lineaments in the east and central parts of the
study site, b) a complex of near-east oriented lineaments
in the west part of the region, c) some near-north-east
oriented linear structures in the north part of the study
site, and d) some near-north-west oriented lineaments in
the south part of the region (Fig. 2 b). Lineaments
revealed by Kh mapping correspond to convergence areas
(Kh negative values) and are connected with a valley
network. A strong dependence of the Crimean valley
network on the regional fault network was noted even by
Muratov (1937). Lineaments recorded on the Kh map are
mostly interpreted as strike-slip faults (Fig. 2 d).
Kv mapping allow us to reveal a) a complex of near-west
oriented lineaments in the east and central part of the
study site, b) a complex of near-north oriented lineaments
mainly in the west part of the region, and c) some near-
north-west oriented linear structures mostly in the south
and the north part of the study site (Fig. 2 c). Lineaments
revealed by Kv mapping correspond to relative
deceleration areas (Kv negative values) and are connected
with terraces. These lineaments are mainly interpreted as
dip-slip faults and thrusts (Fig. 2 d).
Lineaments revealed on both Kh and Kv maps (Fig. 2 b, c)
are interpreted as oblique-slip faults (Fig. 2 d).
The map of morphologically classified faults (Fig. 2 d)
displays a complicated spatial distribution of faults. Dip-
slip, thrust and strike-slip faults unite, as a rule, into
complexes. The complex of near-north-striking strike-slip
faults stretches through areas of different geological
origins. Dip-slip faults stretch, as a rule, across strike-slip
faults. There are some complicated faults which include
dip-slip, strike-slip, thrust and oblique-slip offsets
stretching along the same fault line one after another.
Obviously, the fault map obtained (Fig. 2 d) has a forecast
and somewhat subjective nature. First, it is a result of
slightly ambiguous drawing of fault lines. Second, a visual
analysis of these maps may result in the loss of some
lineaments. Third, this fault map corresponds only to the
single matrix step 3000 m. Using a smaller matrix step
we can obtain a map which will include more faults, while
using a larger step we will obtain a map with fewer faults.
A visual comparative analysis of the fault map obtained
(Fig. 2 d) and factual geological data made it apparent
that a portion of revealed faults correlates with familiar
ones. Another portion of revealed faults does not correlate
with known structures. For the first time the complex of
near-east-striking strike-slip faults is recognised in the
west part of the region. Origin of these structures and
their relationships with the regional tectonics is the
subject of an individual study. It is very important that the
most of the faults revealed and morphologically classified
fit into the main regional fault groups.
However, familiar faults do not all were revealed. On the
whole, this is the result of the use of the single matrix
step. To recognise all the topographically expressed faults
(and to range faults into trans-regional, regional and local
groups) we have to use a set of Kh and Kv maps
correspond to several matrix steps or extents of DEM low-
pass filtering and smoothing (Florinsky, 1992).
5. CONCLUSIONS
For revealing and morphological recognition of
topographically expressed faults it is necessary a) to
calculate Kh and Kv by a DEM processing, b) to stratify
Kh and Kv values into two levels with respect to the zero
value, and c) to map Kh and Kv. Lineaments revealed on
Kh maps indicate faults formed mostly by horizontal
tectonic motions. Lineaments recognised by Kv mapping
correspond to faults formed mainly by vertical motions
and thrusting. Lineaments recorded on both Kh and Kv
maps indicate, as a rule, oblique-slip and gaping faults.
The method was tested by processing the DEMs of the
abstract area with modelled faults and the DEM of the
part of the Crimean Peninsula and the adjacent sea
bottom. For the abstract area the results obtained mostly
correlate with the theoretical basis of the method. For the
real area the comparative analysis of the results obtained
and factual geological data demonstrates that the method
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996