Original scientific paper
https://doi.org/10.17794/rgn.2026.3.14
REMOTE SENSING OF RADIOACTIVE ALTERATION ZONES USING SENTINEL-2 AND SPAD CHLOROPHYLL MEASUREMENTS IN MAMUJU, INDONESIA
Nuraisyiah Pertiwi Kamsir
; Geological Engineering, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Jl. Ganesha No. 10 Bandung, Indonesia.
Asep Saepuloh
; Geological Engineering, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Jl. Ganesha No. 10 Bandung, Indonesia.
*
Very Susanto
; Geological Engineering, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Jl. Ganesha No. 10 Bandung, Indonesia.
Eka Djatnika Nugraha
; Research Center for Safety, Metrology, and Nuclear Quality Technology, Research Organization of Nuclear Technology, The National Research and Innovation Agency of Indonesia (BRIN), Tangerang Selatan 15314, Banten, Indonesia.
* Corresponding author.
Abstract
This study investigates natural radioactive mineralization (uranium–thorium) in Mamuju, West Sulawesi, particularly within the fault-controlled Adang Volcanics, an area known for anomalous natural radiation. The objective was to evaluate vegetation stress as a proxy for radioactive mineralization by integrating satellite data and field validation. We processed
Sentinel-2A data using band ratios (4/2 iron oxide, 4/3 ferric iron, 11/12 clay) and false colour composites to delineate alteration zones. The Red Edge Vegetation Index (REVI; B3, B4, B6) was calculated to detect vegetation stress. Fieldwork in December 2023 collected 68 SPAD chlorophyll measurements from ferns, interpolated with inverse distance weighting, and compared with independent radiation dose rates. The results show a strong correlation between REVI and SPAD (R² = 0.76), confirming the sensitivity of red-edge bands to chlorophyll variability. SPAD values decreased significantly in high-radiation zones, showing a strong negative correlation with dose rate (R² = 0.90). Values of 4–40 were typical in anomalous radiation areas, while >40 characterized lower exposure. Vegetation stress anomalies and satellite-derived Chlorophyll Index overlapped spatially with alteration zones and were concentrated in the Adang Volcanics along structural controls. Species differences among ferns indicated varied sensitivity to radiation. This integrated approach demonstrates the effectiveness of Sentinel-2 alteration composites, REVI, and SPAD validation as a rapid, lowcost framework for early exploration of radioactive minerals while also contributing to environmental radiation hazard assessment.
Keywords
Sentinel-2; Red Edge Vegetation Index (REVI); SPAD chlorophyll; radioactive mineralization; Mamuju
Hrčak ID:
347428
URI
Publication date:
26.5.2026.
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