570 
All those photoalignments which, during assessment, 
presented limited planimetric continuity were excluded 
in accordance with the photointerpretative limits 
established for a regional study. However, this rule 
did have exceptions both in the subsequent classifica 
tion phase (correspondence of photoalignments to oth 
er images) and when the photoalignment belonged to a 
unit developing on a regional scale. Furthermore, any 
photoalignment identified in one type of image was 
sought on the others in order to establish to what 
degree interpretation was correct. 
3 MORPHONEOTECTONIC CLASSIFICATION 
All the tectonically significant natural photoalignm 
ents thus selected were classified according to any 
geomorphological features wich might indicate neotec- 
tonic activity. This classification was based on qua 
lity, quantity, congruence, evidence and meaning of 
the morphoneotectonic features, Panizza & al (1978), 
Panizza & Piacente (1978). 
This method makes it possible to determine any mo 
difications on the earth's surface produced by tecto 
nic movement. In fact, the more recent the movements 
are the more marked and evident the modifications are. 
Therefore, one can infer these movements by means of 
a geomorphological analysis identifying the modifica 
tions . 
There are numerous morphological elements making 
the elaboration a strictly morphogenetic profile pos 
sible and they may indicate recent deformation. The 
geomorphological modifications may be broken down in 
to two types: direct modifications such as escarp 
ments, landslides, fissuring, recurring or aligned 
erosional forms, etc.; indirect modifications such as 
particular forms of slopes, ridges, peaks and of the 
hydrographic network. For example, the development of 
a rectilinear ridge may result from a fault escarpment 
or it may represent a summit or indicate regional up 
lifting. Any discontinuity in altimétrie ridges may 
correspond to transverse faults. A simple escarpment 
may be linked to a fault having a vertical component 
or to area uplifting. Breaks-in-slope and landslide 
areas, as well as particular forms of erosion, may be 
linked to faults. Valleys with simple or double elbows 
may reveal the presence of fault with a horizontal 
component. Movement of this type may produce hooked 
or countercurrent fluvial confluence. Irregularities 
such as suspended confluence or truncated valley for 
example, may be associated with faults having diffe 
rent movements. Strong erosion or sedimentation areas 
could, respectively indicate relative uplifting or 
falling. Thus these and other morphological sculptu 
ring are the indications of recent movements and, 
once they have been identified, verified, studied in 
depth and qualified, they then become proof of fact. 
All the above geomorphological features were asses 
sed and "lines" with a hypothetical neotectonic mea 
ning (lineaments) were associated to them taking into 
account any comparison with the other images. The do 
cument which formed the basis for study was the band 
7 LANDSAT. Herebelow, a description is given of the 
various photointerpretative phases characterizing the 
identification of linear and circular elements and 
leading to their classification as "lineaments" with 
likely neotectonic meaning. Thereafter, the advanta 
ges and disadvantages arising from the use of the dif 
ferent types of images are described. The attention 
of those interested in an interpretational method for 
attributing morphoneotectonic meaning to the obtained 
data is called to Panizza & Castaldini (1985). 
4 INTERPRETATION 
Band 7 LANDSAT images 
The main advantages to using this type of image stem 
from the fact that with this type of regional study it 
is possible to follow continuity and recognize the ae 
rial development of morphoneotectonic elements. A part 
from any implications due to the resolution provided 
by the type of sensor and solar azimut (the latter 
with negligible area effects), the main tectonic 
structures (folds, inverse and direct faults) are hi 
ghly evident, surrounding the Andean high plain to the 
NE and SW. 
In the present study the limitations of this type 
of image basically stem from the lack of details pro 
vided by the sensor: often signs are difficult to de 
fine and, at times controversial or contradictory. 
The clearest morphological evidence appears linked to 
highly developed polychronological forms although they 
do not, consequently, indicate recent movement. Vast, 
highly reflective areas within band 7 further impeded 
the geomorphological study. 
F.C.C. LANDSAT images 
In comparison to the previous images, those in F.C.C. 
made it possible to recognize a greater number of 
features such as, for example, highly eroded areas or 
those characterized by accentuated sedimentation, ele 
ments linked to the hydrographic network, etc.. This 
is so thanks to the different colours characterizing 
the various lithomorphological, vegetational and hy 
drographic entities as well as to a greater contrast 
between areas being eroded and the surrounding areas, 
higher interpretative resolution in those areas pre 
senting elevated reflection in the band 7 LANDSAT 
images and, finally, to a clearer identification of 
morphotectonic features. Moreover, these same images 
have integrated and brought together some characteris 
tic of the arising photoalignments such as: planime 
tric development, frequency and, in extrapolating re 
gional development, bands of isooriented photoalign 
ment . 
SLAR photomosaic images 
The SLAR images proved indispensable, especially in 
the high plain area since high sensor ground resolu 
tion made it possible for the microrelief conformation 
to stand out. It was, thus possible to identify nume 
rous morphological features along the previously iden 
tified photoalignments requiring more precise neotec 
tonic qualification. They likewise made it possible 
to eliminate some photoalignments which were essen 
tially linked to the structural order. They proved 
equally useful in those areas where cloud or plant co 
ver had partially obstructed the LANDSAT images. 
To the E and W of the high plain, in areas where 
reliefs were quite strong, the use of this type of 
image was limited by the presence of extensive areas 
of shadow. 
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REFERENCE 
Panizza, 
nelle D 
se. Tor 
Panizza, 
fologia 
Torino. 
Panizza, 
Analysi 
Working 
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