Sains Malaysiana 55(7)(2026): 1119-1131

http://doi.org/10.17576/jsm-2026-5507-02

 

Structural Lineament Orientation Patterns in Eastern Sabah Derived from Sentinel-1 SAR Data

(Corak Orientasi Kelurusan Struktur di Timur Sabah Diperoleh daripada Data SAR Sentinel-1)

 

KAMILIA SHARIR^1,* , ALEEYAH ADEELA ADNAN², EUGENE SOO ZHEN XIANG¹ & RODEANO ROSLEE²

 

¹Faculty of Engineering (FKJ), Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah, Malaysia

²Faculty of Science & Technology (FST), Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah, Malaysia

 

Diserahkan: 13 Februari 2026/Diterima: 19 Jun 2026

 

Abstract

Geological lineaments provide important insight into regional structural organisation, but their mapping remains challenging in humid tropical regions where dense vegetation, persistent cloud cover and limited bedrock exposure constrain conventional field mapping and optical remote sensing. This limitation is particularly important in Eastern Sabah, northern Borneo, where complex tectonic deformation and major fault systems are present, but spatially consistent regional-scale lineament characterisation remains limited. This study applies Sentinel-1 Synthetic Aperture Radar (SAR) data to investigate structural lineament orientation patterns in Eastern Sabah because SAR imagery is less affected by cloud cover and is sensitive to surface roughness, moisture variation and geomorphological discontinuities. Sentinel-1 GRDH imagery was pre-processed using radiometric calibration, terrain flattening, speckle filtering and terrain correction, followed by multi-directional Sobel edge enhancement and illumination-controlled visualisation. Lineaments were extracted through expert-guided manual digitisation using structural and geomorphological criteria, and were validated using optical imagery and existing geological information to reduce anthropogenic and non-tectonic features. A total of 10,746 validated negative lineaments were mapped and statistically analysed. The Rayleigh test confirms that the lineament orientation distribution is significantly non-uniform, while Kolmogorov–Smirnov tests indicate significant length-distribution differences between the main orientation classes. The extracted lineament network shows strong directional anisotropy, with four dominant orientation sets comprising N–S, NE–SW, NW–SE and E–W trends. The N–S and NE–SW sets form the principal structural trends, while NW–SE and E–W lineaments represent secondary components. NE–SW-oriented lineaments show the greatest apparent continuity, with a maximum length of 3.180 km, suggesting laterally persistent structural corridors. The dominant orientation patterns correspond with major fault trends reported in regional geological maps of Sabah, supporting the tectonic significance of the SAR-derived lineaments. Lineament-density and lithology-density comparisons further indicate that the mapped lineaments reflect the combined influence of structural discontinuities, lithological variation and geomorphological expression. This study demonstrates the usefulness of Sentinel-1 SAR for regional structural lineament mapping in densely vegetated tropical terrain and provides a spatially consistent lineament framework for Eastern Sabah.

Keywords: Eastern Sabah; lineament analysis; Sentinel-1 SAR; structural geology; tectonic fabric

 

Abstrak

Lineamen geologi memberikan maklumat penting tentang organisasi struktur serantau, namun pemetaannya masih mencabar di kawasan tropika lembap yang dilitupi vegetasi tebal, sering mengalami litupan awan dan mempunyai singkapan batuan yang terhad. Kekangan ini amat penting di Sabah Timur, utara Borneo, yang mempunyai deformasi tektonik yang kompleks dan sistem sesar utama, tetapi pencirian lineamen berskala wilayah yang tekal dari segi ruang masih terhad. Kajian ini menggunakan data Synthetic Aperture Radar (SAR) Sentinel-1 untuk menganalisis corak orientasi lineamen struktur di Sabah Timur kerana imej SAR kurang dipengaruhi oleh litupan awan dan peka terhadap kekasaran permukaan, variasi kelembapan serta ketakselanjaran geomorfologi. Imej Sentinel-1 GRDH dipraproses melalui penentukuran radiometrik, perataan medan, penapisan hingar spekel dan pembetulan medan, diikuti dengan penambahbaikan tepi Sobel pelbagai arah dan visualisasi terkawal pencahayaan. Lineamen diekstrak melalui pendigitan manual berpandukan kepakaran menggunakan kriteria struktur dan geomorfologi, serta disahkan menggunakan imej optik dan maklumat geologi sedia ada bagi mengurangkan ciri antropogen dan bukan tektonik. Sebanyak 10,746 lineamen negatif yang telah disahkan dipetakan dan dianalisis secara statistik. Ujian Rayleigh mengesahkan bahawa taburan orientasi lineamen adalah tidak seragam secara signifikan, manakala ujian Kolmogorov–Smirnov menunjukkan perbezaan taburan panjang yang signifikan antara kelas orientasi utama. Rangkaian lineamen yang diekstrak menunjukkan anisotropi arah yang kuat dengan empat set orientasi dominan, iaitu N–S, NE–SW, NW–SE dan E–W. Set N–S dan NE–SW membentuk trend struktur utama, manakala lineamen NW–SE dan E–W mewakili komponen sekunder. Lineamen berorientasi NE–SW menunjukkan kesinambungan nyata yang paling tinggi, dengan panjang maksimum 3.180 km, mencadangkan koridor struktur yang berterusan secara lateral. Corak orientasi dominan ini berpadanan dengan trend sesar utama yang dilaporkan dalam peta geologi wilayah Sabah, sekali gus menyokong kepentingan tektonik lineamen yang diperoleh daripada data SAR. Perbandingan ketumpatan lineamen dan ketumpatan-litologi turut menunjukkan bahawa lineamen yang dipetakan mencerminkan pengaruh gabungan ketakselanjaran struktur, variasi litologi dan ekspresi geomorfologi. Kajian ini menunjukkan kegunaan Sentinel-1 SAR untuk pemetaan lineamen struktur berskala wilayah di kawasan tropika bervegetasi tebal dan menyediakan rangka kerja lineamen yang tekal dari segi ruang bagi Sabah Timur.

Kata kunci: Analisis lineamen; fabrik tektonik; geologi struktur; Sabah Timur; Sentinel-1 SAR

 

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*Pengarang untuk surat-menyurat; email: kamilia.sharir@ums.edu.my