Article Per Year (5 Year)
p-Index From 2021 - 2026
1.623
P-Index
This Author published in this journals
All Journal IJOG : Indonesian Journal on Geoscience JGE (Jurnal Geofisika Eksplorasi) Jurnal Fisika FLUX Spektra: Jurnal Fisika dan Aplikasinya Eksakta : Berkala Ilmiah Bidang MIPA Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal)
Rizki Wulandari
Department of Geophysical Engineering, Faculty of Industrial Technology, Institut Teknologi Sumatera, Lampung, Indonesia.
Aerospace Engineering Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Earth & Planetary Sciences Education Electrical & Electronics Engineering Energy Engineering Environmental Science Materials Science & Nanotechnology Mathematics Mechanical Engineering Physics

Published : 11 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 11 Documents
Search

 1   2 
PEMETAAN KERENTANAN SEISMIK MELALUI ANALISIS MIKROTREMOR HVSR DI WILAYAH KECAMATAN KEMILING DAN SEKITARNYA Ariyanto, Agus; Farduwin, Alhada; Styawan, Yudha; Putri, Intan Andriani; Junian, Wahyu Eko; Prasetyo, Nugroho; Rizki, Reza; Wulandari, Rizki
JGE (Jurnal Geofisika Eksplorasi) Vol 10, No 2 (2024)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v10i2.393

Abstract

Wilayah Kemiling yang terletak di Kota Bandar Lampung sering kali mengalami gempa lokal dengan magnitudo kecil. Gempa ini terjadi secara berulang dan dirasakan di daerah Kemiling dan sekitarnya. Hal tersebut dapat menimbulkan kekhawatiran bagi warga dan dapat merusak bangunan. Fokus utama pada studi ini adalah untuk memahami bagaimana karakteristik tanah dan indeks kerentanan seismik di daerah tersebut. Untuk meminimalisir dampak kerusakan akibat gempa, perlu dilakukan mikrozonasi pada wilayah rawan gempa. Parameter mikrozonasi yang digunakan untuk mengetahui karakteristik tanah antara lain amplifikasi (A0), frekuensi natural (f0), indeks kerentanan seismik (Kg), periode dominan (T0), dan kecepatan gelombang geser hingga kedalaman 30 meter (VS30). Sebanyak 65 titik pengukuran mikrotremor telah diukur di Kecamatan Kemiling dan sekitarnya meliputi kota Bandar Lampung, Kecamatan Gedong Tataan, dan Kecamatan Natar. Pada penelitian ini digunakan analisis metode Horizontal to Vertical Spectral Ratio (HVSR) dan didapatkan bahwa frekuensi natural berkisar antara 0,5-31,47 Hz, periode dominan 0,03-2,0 sekon, amplifikasi 0,76-7,67 kali penguatan, indeks kerentanan seismik 0,05-76,31, dan VS30 49,61-777,80 m/s. Hasil penelitian menunjukkan bahwa wilayah barat daya hingga utara Kemiling memiliki risiko kerentanan yang lebih tinggi dibandingkan wilayah lainnya dengan tipe tanah berupa tanah lunak. Oleh karena itu, diperlukan tindakan mitigasi yang tepat, termasuk pengembangan rencana mitigasi risiko, pemantauan lanjutan, dan keterlibatan aktif masyarakat dalam perencanaan darurat.
PEMETAAN KERENTANAN SEISMIK MELALUI ANALISIS MIKROTREMOR HVSR DI WILAYAH KECAMATAN KEMILING DAN SEKITARNYA Ariyanto, Agus; Farduwin, Alhada; Styawan, Yudha; Putri, Intan Andriani; Junian, Wahyu Eko; Prasetyo, Nugroho; Rizki, Reza; Wulandari, Rizki
JGE (Jurnal Geofisika Eksplorasi) Vol. 10 No. 2 (2024)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v10i2.393

Abstract

Wilayah Kemiling yang terletak di Kota Bandar Lampung sering kali mengalami gempa lokal dengan magnitudo kecil. Gempa ini terjadi secara berulang dan dirasakan di daerah Kemiling dan sekitarnya. Hal tersebut dapat menimbulkan kekhawatiran bagi warga dan dapat merusak bangunan. Fokus utama pada studi ini adalah untuk memahami bagaimana karakteristik tanah dan indeks kerentanan seismik di daerah tersebut. Untuk meminimalisir dampak kerusakan akibat gempa, perlu dilakukan mikrozonasi pada wilayah rawan gempa. Parameter mikrozonasi yang digunakan untuk mengetahui karakteristik tanah antara lain amplifikasi (A0), frekuensi natural (f0), indeks kerentanan seismik (Kg), periode dominan (T0), dan kecepatan gelombang geser hingga kedalaman 30 meter (VS30). Sebanyak 65 titik pengukuran mikrotremor telah diukur di Kecamatan Kemiling dan sekitarnya meliputi kota Bandar Lampung, Kecamatan Gedong Tataan, dan Kecamatan Natar. Pada penelitian ini digunakan analisis metode Horizontal to Vertical Spectral Ratio (HVSR) dan didapatkan bahwa frekuensi natural berkisar antara 0,5-31,47 Hz, periode dominan 0,03-2,0 sekon, amplifikasi 0,76-7,67 kali penguatan, indeks kerentanan seismik 0,05-76,31, dan VS30 49,61-777,80 m/s. Hasil penelitian menunjukkan bahwa wilayah barat daya hingga utara Kemiling memiliki risiko kerentanan yang lebih tinggi dibandingkan wilayah lainnya dengan tipe tanah berupa tanah lunak. Oleh karena itu, diperlukan tindakan mitigasi yang tepat, termasuk pengembangan rencana mitigasi risiko, pemantauan lanjutan, dan keterlibatan aktif masyarakat dalam perencanaan darurat.
Spatial-Temporal Analysis of b-value Before and After the 2018 Lombok Earthquake Using OK1993 Based on Voronoi in the Bali-NTB Region Tata Dwi Hardi Yanti; Yudha Styawan; Rizki Wulandari
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/678

Abstract

This study is motivated by the tectonic complexity of the Bali-NTB region, which results in a heterogeneous seismic distribution and active stress dynamics. The objective is to analyze the spatiotemporal evolution of the b-value using the Ogata-Katsura maximum likelihood estimation (OK1993), combined with Voronoi tessellation as an adaptive spatial partition and the Bayesian Information Criterion (BIC) for ensemble model optimization. Spatial analysis prior to the 2018 event revealed a contradiction in the form of high b-value (>1.0) in Lombok. However, the spatiotemporal analysis successfully explains the condition by identifying a zone of low b-value (<1.0) that developed following the 2007 intermediate sized earthquake through the 2018 mainshock distinct from the 2004 local anomaly that did not progress into a major earthquake. This indicates that the persistence of low b-values is a key indicator of high stress accumulation. Following the 2018 earthquake, the high stress zone expanded across Lombok and West Nusa Tenggara (NTB). This study emphasizes the importance of evaluating statistical reliability, such as N(b) and Median Absolute Deviation (MAD), to avoid misinterpretations due to data limitations, thereby providing a more reliable framework for regional seismic hazard assessment.
Peak Ground Acceleration Mapping of Indonesia Using Complementary Area Source and Smoothed Seismicity Approaches Eka Nioisa Br Surbakti; Ardian Saputra; Rizki Wulandari; Yudha Styawan
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/684

Abstract

 In Indonesia, the choice between area source and smoothed seismicity approaches has been driven by data availability rather than scientific evaluation, and no systematic comparison of both methods at the national scale has been conducted. This study compared both approaches across Indonesia to evaluate their differences in PGA estimation and assess the forecasting skill of the smoothed seismicity model. Both models were applied to the same declustered earthquake catalog with a Magnitude of Completeness of 4.7, b-value of 0.89, and a-value of 8.753, using identical Ground Motion Prediction Equations within a probabilistic seismic hazard analysis framework. Both models consistently identified North Sulawesi as the highest hazard region and Kalimantan as the lowest. The smoothed seismicity model produced higher maximum PGA values of 2.13 g compared to 1.1597 g and 1.5901 g from the area source model at 10% and 2% probability of exceedance in 50 years, respectively. Molchan Diagram validation yielded an Area Skill Score of 0.88 and R-score of 0.656, confirming strong forecasting skill. The two methods are complementary, and their integration within a logic tree framework is recommended for future national-scale PSHA in Indonesia.
Analysis of Fault Plane and Distribution of Coulomb Stress Changes of the Mw 7.8 Earthquake Southwest of Sumatra Gabriela Gabriela; Kelly Lasofia Br Girsang; Rizki Wulandari Wulandari; Yudha Styawan
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/701

Abstract

The Mw 7.8 earthquake that occurred southwest of Sumatra on March 2, 2016, at a depth of 24 km represents a major seismic event within the Sunda subduction zone, significantly influencing regional stress conditions. This study aims to analyze Coulomb stress changes (Δσc), examine stress distribution patterns, and evaluate the most representative fault plane controlling the earthquake source mechanism. The analysis was conducted using the Coulomb Stress Change method based on focal mechanism parameters and finite fault models obtained from the United States Geological Survey (USGS). The results indicate that Nodal Plane 1 (NP1) represents the true fault plane controlling the earthquake mechanism, with maximum stress increase of up to  0.1 bar and orientations from west–east to northwest–southeast. In contrast, Nodal Plane 2 (NP2) acts as a receiver fault, accommodating transferred stress from the main rupture, with similar stress magnitudes oriented north–south to west–east. The observed stress increases on both nodal planes highlight potential zones for aftershock occurrence. This study contributes to a better understanding of earthquake source mechanisms and stress redistribution patterns that may trigger subsequent seismic activity in the southwest  region of Sumatra..
Integrating Time-Dependent and Time-Independent Earthquake Recurrence Models for Fault-Based Seismic Hazard Assessment in the Lampung Region, Southern Sumatra Rizki Wulandari; Yudha Styawan; Satria Bagus Prabowo
Spektra: Jurnal Fisika dan Aplikasinya Vol. 11 No. 1 (2026): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 11 Issue 1, April 2026
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.111.05

Abstract

The Lampung region in southern Sumatra is exposed to significant seismic hazard due to its proximity to the Sunda megathrust and multiple active crustal faults. This study integrates time-independent (Poissonian) and time-dependent (Brownian Passage Time/BPT) earthquake recurrence models to evaluate fault-specific rupture probabilities and their implications for probabilistic seismic hazard assessment (PSHA). This approach systematically bridges the gap between traditional stationary models and the physical reality of seismic cycles, ensuring that the resulting hazard estimates reflect the current elapsed time since the last major rupture. Earthquake catalogs from USGS, BMKG, and historical sources were compiled for shallow events ( 50 km) between 1900–2023, and fault parameters were derived from national hazard maps and published geological studies. Recurrence intervals were estimated for 28 major fault segments across Sumatra, the Sunda Strait, and western Java. Results show strong temporal variability in seismic potential, with the Kumering South segment exhibiting the highest 50-year rupture probability (>50%) due to its elapsed time nearing the estimated recurrence interval. In contrast, segments such as Semangko West-A show markedly reduced short-term probability under the BPT model. PSHA simulations using OpenQuake reveal peak ground acceleration (PGA) values of 0.6–1.5 g for 2% exceedance in 50 years, indicating very high hazard levels in areas adjacent to the Sumatra Fault System. Incorporating time-dependent recurrence provides a more cycle-consistent spatial pattern compared to Poissonian results, reducing overestimation in early-cycle segments and enhancing hazard representation in late-cycle faults. While this study is constrained by uncertainties in historical recurrence intervals and fault slip-rates, these findings provide a more refined academic contribution to regional hazard characterization, supporting more robust risk mitigation strategies in Lampung Province.
Spatial-Temporal Analysis of b-value Before and After the 2018 Lombok Earthquake Using OK1993 Based on Voronoi in the Bali-NTB Region Tata Dwi Hardi Yanti; Yudha Styawan; Rizki Wulandari
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/678

Abstract

This study is motivated by the tectonic complexity of the Bali-NTB region, which results in a heterogeneous seismic distribution and active stress dynamics. The objective is to analyze the spatiotemporal evolution of the b-value using the Ogata-Katsura maximum likelihood estimation (OK1993), combined with Voronoi tessellation as an adaptive spatial partition and the Bayesian Information Criterion (BIC) for ensemble model optimization. Spatial analysis prior to the 2018 event revealed a contradiction in the form of high b-value (>1.0) in Lombok. However, the spatiotemporal analysis successfully explains the condition by identifying a zone of low b-value (<1.0) that developed following the 2007 intermediate sized earthquake through the 2018 mainshock distinct from the 2004 local anomaly that did not progress into a major earthquake. This indicates that the persistence of low b-values is a key indicator of high stress accumulation. Following the 2018 earthquake, the high stress zone expanded across Lombok and West Nusa Tenggara (NTB). This study emphasizes the importance of evaluating statistical reliability, such as N(b) and Median Absolute Deviation (MAD), to avoid misinterpretations due to data limitations, thereby providing a more reliable framework for regional seismic hazard assessment.
Peak Ground Acceleration Mapping of Indonesia Using Complementary Area Source and Smoothed Seismicity Approaches Eka Nioisa Br Surbakti; Ardian Saputra; Rizki Wulandari; Yudha Styawan
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/684

Abstract

 In Indonesia, the choice between area source and smoothed seismicity approaches has been driven by data availability rather than scientific evaluation, and no systematic comparison of both methods at the national scale has been conducted. This study compared both approaches across Indonesia to evaluate their differences in PGA estimation and assess the forecasting skill of the smoothed seismicity model. Both models were applied to the same declustered earthquake catalog with a Magnitude of Completeness of 4.7, b-value of 0.89, and a-value of 8.753, using identical Ground Motion Prediction Equations within a probabilistic seismic hazard analysis framework. Both models consistently identified North Sulawesi as the highest hazard region and Kalimantan as the lowest. The smoothed seismicity model produced higher maximum PGA values of 2.13 g compared to 1.1597 g and 1.5901 g from the area source model at 10% and 2% probability of exceedance in 50 years, respectively. Molchan Diagram validation yielded an Area Skill Score of 0.88 and R-score of 0.656, confirming strong forecasting skill. The two methods are complementary, and their integration within a logic tree framework is recommended for future national-scale PSHA in Indonesia.
Coulomb Stress Change of the 2006 Pangandaran Earthquake (Mw 7.7) and Its Implication for Future Seismicity in the Sunda Subduction Zone Hana Situmorang; Kayla Alexandra; Yudha Styawan; Rizki Wulandari
Jurnal Fisika Flux: Jurnal Ilmiah Fisika FMIPA Universitas Lambung Mangkurat Vol 23, No 2 (2026): Jurnal Fisika Flux: Jurnal Ilmiah Fisika FMIPA Universitas Lambung Mangkurat
Publisher : Lambung Mangkurat University Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/flux.v23i2.26282

Abstract

The Pangandaran earthquake on July 17, 2006, with a magnitude of Mw 7.7, was a tsunami earthquake that triggered a massive tsunami along the southern coast of Java, causing extensive damage and claiming many lives. This study aims to analyze the distribution of Coulomb stress change (ΔCFF) resulting from the 2006 Pangandaran earthquake based on Nodal Plane 1 (NP1), Nodal Plane 2 (NP2), and a finite fault model as validation references. ΔCFF modeling was performed using a rectangular fault plane approach, with interpolation conducted at depths ranging from 0 to 40 km in 10-km intervals to identify the depth yielding the most representative stress distribution. Analysis results indicate that NP1 with strike 284°, dip 9°, and rake 87° at a depth of 10 km produces a ΔCFF distribution pattern most consistent with and representative of the aftershock distribution and closest to the finite fault model pattern. The stress loading zone (ΔCFF > 0) extends northward from the epicenter toward the southern coast of Java, indicating an increased potential for aftershocks in that segment. Meanwhile, the stress-shadow zone (ΔCFF < 0) in the central to western regions reflects the location of the main slip release. The shallow geometry of the NP1 fault plane (dip 9°) contributes to the extensive stress loading zone, reflecting the characteristics of the Sunda subduction megathrust interface. The results of this study indicate that the 2006 Pangandaran earthquake significantly transferred stress to the western and eastern segments of the subduction zone, implying a potential hazard of subsequent seismic activity in the southern Java region.
Analisis Bahaya Gempa Bumi Berdasarkan Nilai Peak Ground Acceleration (PGA) Menggunakan Metode Probabilistic Seismic Hazard Analysis (PSHA) di Wilayah Bali dan Nusa Tenggara Muhammad Hafeezul; Yudha Styawan; Rizki Wulandari
Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal) Vol. 7 No. 1 (2026): Februari
Publisher : Mataram University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/goescienceed.v7i1.1621

Abstract

The Bali, West Nusa Tenggara (NTB), and East Nusa Tenggara (NTT) regions are located within an active tectonic zone influenced by the transition subduction of the Sunda–Banda arc and the presence of surrounding active faults, resulting in a high potential for earthquake hazards. This study was conducted to evaluate seismic hazard through the estimation of Peak Ground Acceleration (PGA) using the Probabilistic Seismic Hazard Analysis (PSHA) method. The analysis is based on an earthquake catalog covering the period 1964–2024 and considers various seismic sources, including shallow background, deep background, active faults, and megathrust sources. Earthquake occurrence models for fault and subduction sources were represented using a truncated exponential model. Ground motion predictions were calculated using several Ground Motion Prediction Equations (GMPEs), which were combined through a logic tree approach. The calculations were performed at bedrock conditions with a Vₛ30 value of 760 m/s, for exceedance probabilities of 10% and 2% within a 50-year period. The results indicate that PGA values for a 10% probability of exceedance range from 0.30 to 1.18 g, while those for a 2% probability of exceedance range from 0.62 to 1.75 g. High PGA values are distributed in the southern and eastern regions, which are adjacent to megathrust segments and active faults with high slip rates, whereas the northern regions exhibit lower PGA values. These results are important for public awareness in earthquake disaster mitigation efforts and for earthquake-resistant building planning.
Co-Authors Agus Ariyanto Ardian Saputra Chung-Han Chan Eka Nioisa Br Surbakti Farduwin, Alhada Gabriela Gabriela Hana Situmorang Junian, Wahyu Eko Kayla Alexandra Kelly Lasofia Br Girsang Muhammad Hafeezul Nurwijayanti Prasetyo, Nugroho Putri, Intan Andriani Reza Rizki Rizki, Reza Satria Bagus Prabowo Tata Dwi Hardi Yanti Yudha Styawan