Impact of multi–source DEM accuracy on integrated InSAR time–series processing for 3D deformation decomposition in the Pasuruan fault zone

Oct 22, 2026

Uploaded by acoobca

Accurate 3D deformation decomposition for fault activity remains challenging with geodetic techniques. This study integrates LOS InSAR, azimuth offset tracking, and GPS Ina–CORS observations to derive robust horizontal and vertical displacement fields. It evaluates three DEMs—SRTM–1, Copernicus, and DEMNAS—for topographic phase correction and verifies vertical accuracy with field RTK. PS–InSAR and SBAS are fused for dense, coherent deformation mapping, while an extended 3D decomposition model unifies PS–InSAR, SBAS, and GPS components with azimuth offsets as a low-weight auxiliary constraint. Applied to the Pasuruan Fault Zone, the framework yields 3D fields (VU, VE, VN) that reveal previously unresolved deformation patterns and supports improved geodetic monitoring where ground observations are limited.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages25

Reading Time1 h 3 min

AccessFree to download

Introduction

Study motivation and tectonic setting

Data availability and GNSS–InSAR fusion background

Earth Science Informatics (2026) 19:114 [https://doi.org/10.1007/s12145-026-02168-w](https://doi.org/10.1007/s12145-026-02168-w) RESEARCH Impact of multi–source DEM accuracy on integrated InSAR time–series processing for 3D deformation decomposition in the Pasuruan fault zone Saiyidinal Fikri1,2 · Ira Mutiara Anjasmara1 · Mokhamad Nur Cahyadi1 · Putra Maulida1 Received: 18 February 2026 / Accepted: 10 June 2026 / Published online: 19 June 2026 © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2026 Abstract The main challenge in analyzing fault activity using geodetic methods is estimating accurate 3D deformation components. This study integrates multiple geodetic datasets including LOS InSAR, azimuth offset tracking, and GPS Ina–CORS observations to generate reliable horizontal and vertical displacement fields. To ensure accurate LOS InSAR deformation estimation, we evaluate the suitability of three DEMs (SRTM–1, Copernicus, DEMNAS) for topographic phase correction and assess their vertical accuracy using field based RTK measurements. Additionally, PS–InSAR and SBAS are combined to achieve high pixel density and temporal coherence in deformation mapping. The methodological innovation of this study lies in the development of an extended 3D decomposition model that, unlike existing approaches, jointly incorporates PS–InSAR, SBAS, azimuth offset tracking, and GPS horizontal velocity components into a unified matrix solution. This study adopts an extended 3D decomposition that jointly incorporates PS–InSAR, SBAS, GPS horizontal velocities, and where quality permits azimuth offset tracking as a low–weight auxiliary constraint. Given the limited azimuthal sensitivity of Sentinel–1 for interseismic signals, azimuth offsets are down–weighted in the WLS inversion and evaluated via ablation to ensure they do not degrade the north–south component. By applying this framework to the Pasuruan Fault Zone in East Java, Indonesia, the resulting 3D deformation fields (VU , VE , VN ) effectively characterize local tectonic activity and reveal previously unresolved deformation patterns. The proposed integration approach demonstrates strong scientific potential for enhancing geodetic monitoring in areas with limited ground–based observations. Keywords DEM · PS-InSAR · SBAS · Azimuth offset tracking · GPS · Decomposition 􀀍 Ira Mutiara Anjasmara[i.anjasmara@its.ac.id](i.anjasmara@its.ac.id) Saiyidinal Fikri [saiyidinal.fikri@gmail.com](saiyidinal.fikri@gmail.com) Mokhamad Nur Cahyadi [cahyadi@geodesy.its.ac.id](cahyadi@geodesy.its.ac.id) Putra Maulida [putra@its.ac.id](putra@its.ac.id) 1 Department of Geomatics Engineering, Institut Teknologi Sepuluh Nopember, Sukolilo Campus, Surabaya 60111, Indonesia 2 Geodesy Undergraduate Program, Institut Teknologi Padang, Gajah Mada, Padang 25122, Indonesia Introduction East Java is situated in the convergence zone of the Indo– Australian and Eurasian plates, with the former moving 6–7 cm per year towards the latter. This interaction creates a southern fault line and the Sunda Trench (Clements et al. 2009) . The Baribis–Kendeng fault system remains active and continues to change (Koulali et al. 2017) . The Kendeng thrust fault, also known as the Java Back–Arc Thrust, is a long geological feature extending from West Java to East Java (Widjajanti et al. 2020) . Studies of the Earth’s crust have found that shallow faults are present along the Pasuruan Fault, although the extent of deformation remains undisclosed. According to seismological research, earthquakes in the Pasuruan fault area result from normal faulting (Marliyani et al. 2019). The Ina–CORS (Indonesia Continuously Operating Reference Stations) is monitoring the changes in the Earth’s crust in East Java. However, due to the low number of stations in this area, both theresolution and the network’s capability in the most active fault zones are weakened (Maulida et

FAQs

What geodetic datasets are integrated to obtain the 3D displacement fields?

The study integrates LOS InSAR, azimuth offset tracking, and GPS Ina–CORS observations to generate horizontal and vertical displacement fields.

How does the paper handle topographic phase correction uncertainty from DEMs?

It evaluates three DEM sources (SRTM–1, Copernicus, and DEMNAS) for suitability in topographic phase correction and assesses their vertical accuracy using field-based RTK measurements.

Why are azimuth offsets down-weighted in the decomposition model?

Because Sentinel-1 has limited azimuthal sensitivity to interseismic signals, azimuth offsets are treated as a low-weight auxiliary constraint and validated via ablation to avoid degrading the north–south component.

Oct 22, 2026

Uploaded by acoobca