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All Journal Jurnal Fisika Unand GEA, Jurnal Pendidikan Geografi Journal of Geoscience, Engineering, Environment, and Technology Journal of Applied Geospatial Information Jurnal Geosains dan Teknologi Geodika: Jurnal Kajian Ilmu dan Pendidikan Geografi Journal of Earth and Marine Technology (JEMT) GeoEco
Ongky Anggara
Teknik Geomatika, Institut Teknologi Sumatera
Humanities Civil Engineering, Building, Construction & Architecture Earth & Planetary Sciences Education Electrical & Electronics Engineering Energy Engineering Environmental Science Materials Science & Nanotechnology Physics Social Sciences Transportation

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Analysis Of Presumed Land Subsidence In The Cities Of Lampung Province Using InSAR And GNSS Data Alif, Satrio Muhammad; Anggara, Ongky; Perdana, Redho Surya; Hasannah, Uswatun; Azizah, Fadhillah Nur
Journal of Geoscience, Engineering, Environment, and Technology Vol. 9 No. 3 (2024): JGEET Vol 09 No 03 : September (2024)
Publisher : UIR PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25299/jgeet.2024.9.3.14096

Abstract

Land subsidence is a naturally occurring phenomenon that has become a growing concern in various regions, including Lampung Province. In this study, we investigate land subsidence in various cities within Lampung Province, Indonesia, utilizing Sentinel-1A using Sentinel-1A satellite image data from the period 2014 to 2022. The cities of Lampung Province analyzed in this study were Liwa, Kota Agung, Kalianda, Sukadana, Bandar Lampung and Krui. The method used is Interferometric Synthetic Aperture Radar (InSAR) with the Small Baseline Area Subset (SBAS) technique. Furthermore, to validate and improve the accuracy of land subsidence measurements, the Global Navigation Satellite System (GNSS) velocities were utilized. The land subsidence result obtained in this study is presumed land subsidence. The cities that experienced land subsidence was Kalianda, Sukadana, Bandar Lampung and Krui ranging from ~3 mm/yr to ~15 mm/yr. Meanwhile, the areas that experienced an uplift were the Liwa and Kota Agung cities.
Uji Signifikansi Stasiun GPS Kontinu dan Periodik dalam Identifikasi Pergerakan Koseismik Ongky Anggara; Satrio Muhammad Alif; Andhika Wahyu Pratama; Wendi Melvin Hutabarat
Jurnal Fisika Unand Vol 13 No 1 (2024)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.13.1.89-95.2024

Abstract

Pengukuran pergerakan bumi dengan menggunakan sistem GPS telah menjadi bagian penting dalam pemahaman deformasi kerak bumi yang berkaitan dengan aktivitas seismik. Dalam penelitian ini dilakukan uji   signifikansi dari stasiun GPS yang beroperasi secara kontinu dan periodik dalam mengidentifikasi pergerakan koseismik gempa Pesisir Barat pada 10 Maret 2020 (M5,8)   dan gempa Bengkulu pada 19 Agustus 2020 (M6,8). Pengolahan data GPS menggunakan perangkat lunak GAMIT/GLOBK yang bertujuan   untuk mendapatkan koordinat dan nilai pergeseran koseismik. Hasil penelitian menunjukan bahwa rata-rata titik tidak menunjukan pergeseran secara signifikan baik dari data GPS kontinu maupun data GPS periodik. Terdapat satu titik pengamatan yang menunjukkan   pergeseran secara signifikan yaitu stasiun pengamatan PRKB yang menunjukkan   pergeseran sebesar ~2-3 mm. Uji signifikansi dipengaruhi oleh nilai pergeseran koseismik dan standar deviasinya yang dipengaruhi mekanisme gempa. Uji signifikansi dari pengamatan stasiun GPS menunjukkan   tidak terdapat perbedaan baik dari data GPS secara kontinu maupun GPS secara periodik pada uji signifikansi karena   gempa yang diamati relatif kecil sehingga menghasilkan pergeseran koseismik yang relatif kecil.
Analisis Deformasi di Lampung dan Selat Sunda Berdasarkan Data GNSS tahun 2018 hingga 2021 Ongky Anggara; Muhammad Ario Eko Rahadianto; Satrio Muhammad Alif; Een Lujainatul Isnaini
Jurnal Fisika Unand Vol 13 No 5 (2024)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.13.5.637-643.2024

Abstract

The Lampung Province and Sunda Strait have a seismic gap zone with the potential for major earthquakes in the future. This study analyzes the deformation occurring in this region using continuous Global Navigation Satellite System (GNSS) station data from Indonesia Continuously Operating Reference Station (InaCORS) and Sumatran GPS Array (SuGAr) from 2018 to 2021.5. The GNSS data was processed using the Bernese 5.2 scientific software, applying least squares for velocity changes and statistical tests to analyze significance. The data processing was carried out in two schemes: the first scheme covering 2018-2020, and the second covering 2019-2021. The results of the deformation analysis from 2018 to 2021, using two continuous GNSS data processing schemes, showed velocity changes relative to the Sundaland Plate ranging from ~2 mm/year to ~20 mm/year. In the eastern region of the Sumatra fault, the velocity changes were smaller, around ~5 mm/year, due to the minimal influence of tectonic activity. However, in the Sunda Strait region, the deformation was influenced by volcanic activity. The deformation occurring in Lampung Province and the Sunda Strait, based on GNSS velocity changes, significantly contributes to tectonic and volcanic activities.
COSEISMIC DEFORMATION OF THE 2020 BENGKULU MW 6.8 EARTHQUAKE USING INSAR DATA Ongky Anggara; Satrio Muhammad Alif
GeoEco Vol 11, No 1 (2025): GeoEco January 2025
Publisher : Universitas Sebelas Maret (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/ge.v11i1.90987

Abstract

An earthquake with a seismic moment magnitude of Mw 6.8 occurred in Bengkulu province, located on the southwestern coast of Sumatra, on August 18, 2020. This study aims to assess the application of the differential interferometric synthetic aperture radar (DInSAR) method to detect and analyze coseismic deformation due to this earthquake using the Sentinel-1A radar satellite. The results of the DInSAR did not yield significant coseismic signals with the range of Line of Sight (LOS) displacement of ~-40 mm to ~40 mm. The InSAR data did not detect clear deformation patterns or displacements associated with the August 18, 2020 earthquake. Further investigations are needed to understand the limitations of InSAR in detecting coseismic signals for this specific event. Integrating these datasets can provide a more comprehensive understanding of the earthquake source, fault characteristics, and associated deformation patterns.
RAPID MAGNITUDE ESTIMATION OF 2019 M6.9 BANTEN EARTHQUAKE USING GNSS 1HZ Ongky Anggara; Novia Rohmadona; Redho Surya Perdana; Satrio Muhammad Alif; Een Lujainatul Isnaini; Muhammad Al Kautsar
GeoEco Vol 12, No 2 (2026): GeoEco July 2026
Publisher : Universitas Sebelas Maret (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/ge.v12i2.109235

Abstract

Rapid magnitude estimation remains challenging in Indonesia due to the limited evaluation of high-rate Global Navigation Satellite System (GNSS) data and the lack of region-specific validation of existing Peak Ground Displacement (PGD) scaling relations for earthquake early warning applications. This study investigates the performance of high-rate GNSS data (1 Hz) for rapid magnitude estimation of the August 2 2019, Banten earthquake (Mw 6.9). Using 15 InaCORS stations provided by the Geospatial Information Agency of Indonesia, the data were processed using Precise Point Positioning with Ambiguity Resolution (PPP-AR). PGD values were extracted and applied to three empirical scaling relations proposed by Melgar et al. (2015), Crowell et al. (2016), and Ruhl et al. (2019). This study presents a comparative evaluation of multiple PGD scaling models using real Indonesian GNSS data, providing insight into their performance in a tectonic setting that remains underrepresented in previous studies. The results show that all models successfully converged to Mw 6.9, with convergence times ranging from 20 to 160 seconds after the earthquake origin time. However, this study is limited by the analysis of a single earthquake event and the use of global scaling relations that are not specifically calibrated for Indonesian tectonic conditions. These findings demonstrate the potential of high-rate GNSS as a complementary tool to seismic sensors for rapid magnitude estimation. The integration of GNSS into the Indonesia Tsunami Early Warning System (InaTEWS) is therefore recommended to improve the reliability and timeliness of earthquake and tsunami early warning.
Assessment of Cross-Section Interval Variations for Earthwork Volume Estimation on Straight and Curved Road Alignments Muhammad Afan Akbar; Meraty Ramadhini; Ongky Anggara
Journal of Applied Geospatial Information Vol. 10 No. 1 (2026): Journal of Applied Geospatial Information (JAGI)
Publisher : Politeknik Negeri Batam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30871/jagi.v10i1.13204

Abstract

Cross-sectional interval variations on cut and fill volume estimation for straight and curved road alignments. Unlike previous studies that focused on a single road geometry, this study compares straight and curved road sections under identical survey conditions. Data were collected using an Electronic Total Station with cross-sectional intervals of 10 m, 25 m, and 50 m, representing dense, moderate, and sparse survey sampling scenarios commonly applied in road construction projects. Earthwork volumes were calculated using the Average End Area method based on SWDTM, Microsoft Excel, and AutoCAD Civil 3D. A paired sample t-test was applied to evaluate the significance of volume differences among interval scenarios. The results show that larger cross-sectional intervals produced greater discrepancies in cut and fill volume calculations. On straight road sections, estimated fill volumes ranged from 237.050 m³ to 254.250 m³, while on curved road sections they ranged from 333.100 m³ to 360.250 m³. Statistical analysis indicated that all calculated t-values were lower than the critical t-value at the 95% confidence level, suggesting that interval variations did not produce statistically significant differences in calculated volumes. However, wider intervals generated larger practical discrepancies and relative errors. These findings indicate that a 25 m cross-sectional interval provides a practical balance between survey efficiency and earthwork volume estimation reliability for road construction projects.
Co-Authors Aditya Rizqiansyah Andhika Wahyu Pratama Azizah, Fadhillah Nur Ching, Kuo-En Een Lujainatul Isnaini Een Lujainatul Isnaini Een Lujainatul Isnaini Jenny Melynda Siagian Krama, Agel Vidian Meraty Ramadhini Muhammad Afan Akbar Muhammad Al Kautsar Muhammad Ario Eko Rahadianto Muhammad Ario Eko Rahadianto Novia Rohmadona Perdana, Redho Surya Putri Ferlia Cahyani Redho Surya Perdana Satrio Muhammad Alif Siagian, Jenny Melynda Siburian, Yesica Tumim Siregar, Ribhan Nafiz Vidiya Ristiana Wendi Melvin Hutabarat