Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986
Evaluation of digitally processed Landsat imagery and SIR-A
imagery for geological analysis of West Java region, Indonesia
Indroyono Soesilo & Richard A.Hoppin
Department of Geology, University of Iowa, Iowa City, USA
ABSTRACT : A regional geologic investigation of West Java area utilizing contrast-enhanced
False Color Composite and Band-7 MSS Landsat imagery has resulted in the interpretation of
regional geologic structure, the delineation of four physiographic zones and one volcanic chain
in the area.
The Band Ratio and the Principal Component Transformation were applied to Landsat data of
the Sukabumi and Lembang areas to provide iirproved lithologic discrimination, while the Edge
Enhancement technique applied to the same areas increased the capabilities for structural
interpretation. A "multi-step interpretation" conducted to Landsat MSS data from this tropical
region discriminated thirteen different lithologic terrains in the Sukabumi area and eleven
different lithologic terrains from the Lembang area, while the Edge Enhanced imagery of these
two sites provide additional understanding of the Cimandiri fault zone, the Lembang fault and
the N - S maximum principal stress responsible for the development of structural patterns in
this region.
The SIR-A imagery of West Java area increased the topographic details lead to their
structural geologic interpretations and used as additional information to the Landsat MSS data.
INTRODUCTION
The current impressive developments in remote sensing
technology has been further advanced by major
breaktroughs in aerial surveys and satellite
technologies. Added to advances in computer
technology which are providing enhanced imagery of
remotely sensed data from satellite and airborne
sensors, better analyses of earth surface phenomena
are possible.
The development of the radar remote sensing system,
with its capabilities as a day or night, all weather,
"vegetation penetration"- active imaging system, has
made the survey of tropical regions more accessible.
The radar sensing system has evolved recently from a
more constrained Side Looking Airborne Radar system
(SLAR) into the Synthetic Aperture Radar system (SAR)
and from an airborne plaform into Satellite and Space
Shuttle platform (Seasat SAR and Shuttle Imaging
Radar).
Geological investigation of tropical areas, such as
found in Indonesia, using remote sensing technology
often has to cope with environmental variables such as
dense vegetation canopy, the high rate of weathering,
weather and climatic factors. The capabilities of this
technology to assist in solving geological problems in
this tropical region has recently been accessed in
conjuction with the Natural Resources Inventory
program currently being conducted by the Indonesian
government (Asmoro, 1978).
This paper is especially directed toward determining
the capabilities of Landsat and its digitally
processed imagery and of SIR-A imagery for lithologic
and structural geologic investigations in this
tropical environment. Attention is focused
particularly of determining the methods on pattern
recognition through interpretation of tone, texture
and shape of the surface.
A section of West Java was chosen as the test area
for this investigation. The digital image processing
and analysis were concentrated in two test sites
within the investigated area, the Sukabumi and Lembang
areas - where a ground investigation was also
conducted (Figure:1 ). This location was selected
because all of West Java's physiographic zones
(Bemmelen, 1949) are represented in this area and each
of these zones exhibits a typical lithologic character
which can be discernable on various digitally
processed Landsat imagery. This region is also
tectonically active and is a p>art of the western
Indonesia island arc system. The structural analysis
of this region will provide an important tectonic
synthesis for identification of seismic hazards and
for exploration of economic minerals.
Figure 1: Index map of Landsat 5 and SIR-A coverage,
West Java - Indonesia. Also shown the two test sites,
Sukabumi area (SW) and Lenbang area (NE).
