Using Landsat 8 Remote Sensing Data Set

for Thermal Anomaly Mapping

at Pantar Geothermal Area, East Nusa Tenggara, IndonesiaSantia Ardi MUSTOFA1,3, Md. Bodruddoza MIA2,3, Jun NISHIJIMA3, Yasuhiro FUJIMITSU3

¹Center for Coal, Mineral, and Geothermal Resources, Ministry of Energy and Mineral Resources of the Republic of Indonesia, Bandung, Indonesia

²Department of Geology, University of Dhaka, Dhaka, Bangladesh

³Laboratory of Geothermics, Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, Fukuoka, Japan

Correspondent author: santia.ardi@gmail.com

Identifying of alteration distribution is a preliminary study

in geothermal exploration. It can be observed when these

alteration products are exposed at the surface. The remote

sensing techniques can be performed to recognize spatial

alteration pattern as one of the standard procedures in

exploration geology, due to its speed and price (Yetkin, et.

al., 2004). Additionally, the purpose of the study is to

clarify the distribution of alteration pattern as well as

thermal anomaly in an initial stage of geothermal

exploration.

International Symposium on Earth Science and Technology 2016

INTRODUCTION

STUDY AREA

Study area in True Color Composition (RGB 4,3,2)

MATERIALS AND METHOD

Landsat 8 Bands Specification (USGS, 2016)

ANALYSIS AND RESULT

Color CompositeRed color represents vegetated

area, blue color represents the

contrasts of temperature, while the

bright (white) color represents the

area with hydrothermal alteration

zones.

RGB 5,7,10

RGB 7, 3, 5

Blue color represents vegetated

area and the brighter pixels

represents clay minerals that

indicate hydrothermal alteration

zone.

RGB 7, 5, 3

The reddish color shows iron oxide

minerals. Green color corresponds

to vegetated area. The brighter

color represents hydrothermal

alteration zone.

Band Ratio

Altered iron-oxide is reflected as

light purple color, the magenta color

represents vegetated area. The green

color represents clay minerals

distribution.

Abram Ratio RGB 6/7, 4/3, 5/6

Light purple color represents iron-

oxide minerals distributed around

the Sirung crater, the cyan color

represents the distribution of clay

minerals.

Chica-Olma Ratio RGB 6/7, 6/5, 4/2

Blue color represents clay minerals

distributed around the Sirung crater

and cyan color represents vegetated

area.

Kaufmann Ratio RGB 7/5, 4/3, 5/6

From the band ratio analysis above, the altered minerals

are distributed well around the crater and spotted in

northeast of the study area.

Principal Component AnalysisPCA for bands 2-7

Eigenvector Band 2 Band 3 Band 4 Band 5 Band 6 Band 7 Eigenvalue

PC1 0.042 0.124 0.151 0.789 0.521 0.256 21143981.278.95%

PC2 -0.307 -0.357 -0.515 0.511 -0.329 -0.379 4489626.495.71%

PC3 -0.351 -0.424 -0.406 -0.319 0.584 0.299 1076948.199.74%

PC4 -0.503 -0.281 0.454 0.086 -0.415 0.532 45859.699.91%

PC5 0.491 0.019 -0.496 0.072 -0.321 0.635 19795.199.98%

PC6 -0.536 0.773 -0.308 -0.036 -0.058 0.125 5235.5 100%

Eigenvector Band 2 Band 5 Band 6 Band 7 Eigenvalue

PC1 -0.249 -0.522 -0.815 -0.031 20429863.7 85%

PC2 -0.536 -0.576 0.544 -0.291 2950952.5 98%

PC3 0.051 -0.348 0.172 0.920 402443.1 99%

PC4 -0.805 0.523 -0.099 0.261 34856.5 100%

PCA for bands 2, 5, 6, 7

Eigenvector Band 2 Band 4 Band 5 Band 6 Eigenvalue

PC1 0.136 0.526 0.839 0.032 19556436.4 83%

PC2 0.636 0.516 -0.441 0.367 3163372.1 96%

PC3 0.518 -0.670 0.319 0.426 790412.5 99%

PC4 0.555 -0.096 0.001 -0.826 31785.7 100%

PCA for bands 2, 4, 5,6

PC4 image of bands 2,5,6,7 (H image)

H image shows the hydroxyl

minerals displayed as bright pixels

around the Sirung crater.

PC4 image of bands 2,4,5,6 (F image)

F image shows the oxide minerals

displayed as bright pixels around the

Sirung crater.

RGB H, H+F, F

Hydroxyl minerals are displayed as

light orange color in map. While

the iron oxide mineral is displayed

as light blue color. The distribution

of the iron oxide minerals spreads

around the Sirung crater with

wider distribution.

Land Surface Temperature

Based on our analysis, an area

with anomalous heat is centred

around Mount Sirung's crater.

The distribution of this

anomalous heat spreads to the

south of the crater, and to the

west along a northwest-

southeast trending lineament

Heat Anomaly Using Band 10

CONCLUSIONHydrothermal alteration mapping in the study area was

successfully carried out using composite colour and band

ratio methods. PCA transformations of bands 2, 5, 6, 7 and

bands 2, 4, 5, 6 were carried out to determine the

distribution of hydroxyl and iron oxide minerals in this

area. Based on these three methods, the distribution of

alteration minerals around Mount Sirung's crater was

determined. Iron oxide minerals had a wider distribution

than hydroxyl minerals, which were centred just around the

crater. The distribution of hydrothermal alteration

minerals corresponds well with the heat anomaly

characterised by LST methods. Based on our analysis, we

conclude that the formation of hydrothermal alteration

minerals is closely associated with anomalous heat in the

Pantar Geothermal Area.

REFERENCESAguilera, F., Layana, S., Rodriguez-Diaz, A., Gonzalez,

C., Cortes, J., & Inostroza, M. (2016).

Hydrothermal Alteration, Fumarolic Deposits and

Fluids from Lastarria Volcanic Complex: A

Multidisciplinary Study. Andean Geology, 42, pp.

166-196.

Loughlin, W. (1991). Principal Component Analysis for

Alteration Mapping. Photogrammetric Engineering

and Remote Sensing, 57, (pp. 1163-1169).

Nur Hadi, M., & Kusnadi, D. (2015). Survei Geologi dan

Geokimia Daerah Panas Bumi Pulau Pantar

Kabupaten Alor, Provinsi Nusa Tenggara Timur.

Prosiding Hasil Kegiatan Lapangan Pusat Sumber

Daya Geologi Tahun Anggaran 2015, (pp. 77-90).

Bandung.

USGS. (2016). Landsat 8 (L8) Data Users Handbook.

South Dakota.

Yetkin, E., Toprak, V., & Süzen, M. (2004). Alteration

Mapping by Remote Sensing: Application to

Hasandag – Melendiz Volcanic Complex, Central

Turkey. Geo-Imagery Bridging Continents XXth

ISPRS Congress. Istanbul.

ACKNOWLEDGEMENT

The authors would like to show their sincere gratitude to

JICA for organizing the ‘Intensive Training for Geothermal

Resource Engineers’ program. Also thank to Department of

Earth Resources Engineering of Kyushu University,

especially to Laboratory of Geothermics who have helped

in this study. Thanks to NASA which has been producing

Landsat 8 for free. The authors also thank to the MEMR of

the Republic of Indonesia for giving opportunity to

participate in this program.

Remote sensing is among the most important methods in

the early stages of a geothermal survey, especially for

mapping hydrothermal alteration. In this study,

conventional methods were applied to determine the

distribution of the hydrothermal anomaly in the Pantar

Geothermal Area, using Landsat 8 satellite images. The

distribution of hydrothermal mineral alteration around the

Mount Sirung was successfully determined by applying

colour composite, band ratio, and principal component

analysis techniques. The distribution of these

hydrothermal alteration minerals was correlated with the

thermal anomaly distribution derived from land surface

temperatures in the study area.

ABSTRACT

The image used in this study is Landsat-8 (OLI and TIRS )

that was acquired on July 9th 2016. The methods used in

this study are:

• Color Composite

• Band Ratio

• Principal Component Analysis (PCA)

• Land Surface Temperature (LST)

Landsat-8 OLI and TIRS Bands (µm) Landsat-8 OLI and TIRS Bands (µm)

30 m Coastal/Aerosol 0.435-0.451Band 1 100 m TIR-1 10.60-11.19 Band 10

30 m Blue 0.452-0.512Band 2 100 m TIR-2 11.50-12.51 Band 11

30 m Green 0.533-0.590Band 3 30 m SWIR-2 2.107-2.294Band 7

30 m Red 0.636-0.673Band 4 15 m Pan 0.503-0.676Band 8

30 m NIR 0.851-0.879Band 5 30 m Cirrus 1.363-1.384Band 9

30 m SWIR-1 1.566-1.651Band 6

The study area is located in

Pantar Geothermal Area,

Pantar Island in East Nusa

Tenggara Province. It lies

within the tectonic setting

of the Inner Banda volcanic

arc, dominated by volcanic

rocks from the still active

Mount Sirung (Nur Hadi

and Kusnadi, 2015)