Spatial Analysis of the Seismic Gap Zone Based on Multiparameter Seismotectonics in Southern East Java as an Indicator of Megathrust Earthquake Potential

Authors

  • Diva Maharani Putri Geophysics Department, Padjadjaran University, Bandung, 40132
  • Nanda Maharani Physics Department, Brawijaya University, Malang, 65145
  • Ilham Ilham Malang Geophysical Station, Agency for Meteorology, Climatology and Geophysics (BMKG), Malang, 65165
  • Riska Yulinda Malang Geophysical Station, Agency for Meteorology, Climatology and Geophysics (BMKG), Malang, 65165

DOI:

https://doi.org/10.70561/geocelebes.v9i2.44633

Keywords:

Earthquake return period, locked segment, subduction, tectonic stress

Abstract

The southern region of East Java is located above an active subduction zone, where the Indo-Australian Plate is subducting beneath the Eurasian Plate. This tectonic condition makes the region potentially susceptible to large-scale megathrust earthquakes. This study aims to characterize the suspected seismic gap segments in the southern subduction zone of East Java, with a primary focus on the area between Pacitan and Lumajang. The approach used is based on high-resolution seismotectonic spatial analysis, combining three main parameters: seismicity distribution, earthquake return period estimates, and a-values and b-values as indicators of tectonic activity and stress condition. The analyzed data covers a long period of time, from 1910 to 2025, and was compiled by the BMKG and USGS catalogs. The results of the analysis show that the Pacitan-Lumajang segment experiences a lack of earthquake activity in the plate interface, although this area is tectonically active. In addition, this segment has a very long return period (> 500 years for Mw7 and > 4,000 years for Mw8), accompanied by low a-value and b-value, indicating low earthquake frequency and high stress accumulation. These findings indicate that the segment is a locked zone that has the potential to release large amounts of energy in the future. The results of this study provide an initial contribution in understanding the spatial distribution of seismic activity in the southern region of East Java, and can be used as supporting considerations in initial disaster risk assessments, especially in densely populated coastal areas.

References

Adam, C., Vidal, V., Grosse, P., & Ichihara, M. (2022). Correlations Between Subduction of Linear Oceanic Features and Arc Volcanism Volume Around the Pacific Basin. Geochemistry, Geophysics, Geosystems, 23(12), e2022GC10553. https://doi.org/10.1029/2022GC010553

Aribowo, S., Husson, L., Natawidjaja, D. H., Authemayou, C., Daryono, M. R., Puji, A. R., Valla, P. G., Pamumpuni, A., Wardhana, D. D., de Gelder, G., Djarwadi, D., & Lorcery, M. (2022). Active Back-Arc Thrust in North West Java, Indonesia. Tectonics, 41(7), e2021TC007120. https://doi.org/10.1029/2021TC007120

Artemieva, I. M. (2023). Back-arc basins: A global view from geophysical synthesis and analysis. Earth-Science Reviews, 236, 104242. https://doi.org/10.1016/j.earscirev.2022.104242

Aslamia, H., & Supardi, Z. A. I. (2022). Analisis Parameter a-Value dan b-Value sebagai Mitigasi Bencana Gempa Bumi di Nusa Tenggara Timur. Jambura Physics Journal, 4(1), 14–27. https://doi.org/10.34312/jpj.v4i1.13815

Bazrafshan, A., Khaji, N., & Paolucci, R. (2024). On the effect of background seismicity in physics-based earthquake simulations. Journal of Asian Earth Sciences, 274, 106261. https://doi.org/10.1016/j.jseaes.2024.106261

Bilek, S. L., & Lay, T. (2018). Subduction zone megathrust earthquakes. Geosphere, 14(4), 1468–1500. https://doi.org/10.1130/GES01608.1

da Costa, J., Maryanto, S., Juwono, A. M., Pires, J., Almeida, G. P. d. S., & da Costa, L. T. (2024). Preliminary Study of a-value and b-value of Earthquake at Timor Leste Period 1975 – 2022. 10(SpecialIssue), 711–718. https://jppipa.unram.ac.id/index.php/jppipa/article/view/8578

Dong, M., Hao, T., Xu, L., Zhang, J., Zhang, J., Lü, C. C., & He, Q. (2024). Subduction without volcanic arc magma: Insights from two young subduction zones in the western Pacific. Tectonophysics, 874, 230231. https://doi.org/10.1016/j.tecto.2024.230231

Ernandi, F. N., & Madlazim, M. (2020). Analisis Variasi a-Value dan b-Value dengan Menggunakan Software Zmap V.6 sebagai Indikator Potensi Gempa Bumi di Wilayah Nusa Tenggara Barat. Jurnal Inovasi Fisika Indonesia, 9(3), 24–30. https://doi.org/10.26740/ifi.v9n3.p24-30

Gardner, J. K., & Knopoff, L. (1974). Is the sequence of earthquakes in Southern California, with aftershocks removed, Poissonian?. Bulletin of the Seismological Society of America, 64(5), 1363–1367. https://doi.org/10.1785/BSSA0640051363

Godang, S., Saputro, S. P., & Li, H. (2024). The slab failure in Central Java (Indonesia): New insight into its tectonic setting and origin. Solid Earth Sciences, 9(3), 100199. https://doi.org/10.1016/j.sesci.2024.100199

Gunawan, E., Meilano, I., Hanifa, N. R., & Widiyantoro, S. (2017). Effect of coseismic and postseismic deformation on homogeneous and layered half-space and spherical analysis: Model simulation of the 2006 Java, Indonesia, tsunami earthquake. Journal of Applied Geodesy, 11(4), 207–214. https://doi.org/10.1515/jag-2017-0009

Gunawan, E., & Widiyantoro, S. (2019). Active tectonic deformation in Java, Indonesia inferred from a GPS-derived strain rate. Journal of Geodynamics, 123, 49–54. https://doi.org/10.1016/j.jog.2019.01.004

Gutenberg, B., & Richter, C. F. (1944). Frequency of Earthquakes in California. Bulletin of the Seismological Society of America, 34(4), 185–188. https://doi.org/10.1785/BSSA0340040185

Haerudin, N., Alami, F., & Rustadi, R. (2019). Mikroseismik, Mikrotremor dan Microearthquake dalam Ilmu Kebumian. Pusaka Media

Hayes, G. P., Moore, G. L., Portner, D. E., Hearne, M., Flamme, H., Furtney, M., & Smoczyk, G. M. (2018). Slab2, a comprehensive subduction zone geometry model. Science, 362(6410), 58–61. https://doi.org/10.1126/science.aat4723

Hisyam, F., Susilo, A., Anshori, M., & Hasan, M. F. R. (2024). Spatio-Temporal Variation Seismicity Pattern in East Java Between 2002 and 2022 Based on the b-value and Seismic Quiescence z-value. Trends in Sciences, 21(4), 7608. https://doi.org/10.48048/tis.2024.7608

Hollingsworth, J., Ye, L., & Avouac, J.-P. (2017). Dynamically triggered slip on a splay fault in the Mw 7.8, 2016 Kaikoura (New Zealand) earthquake. Geophysical Research Letters, 44(8), 3517–3525. https://doi.org/10.1002/2016GL072228

Hutchings, S. J., & Mooney, W. D. (2021). The Seismicity of Indonesia and Tectonic Implications. Geochemistry, Geophysics, Geosystems, 22(9), e2021GC009812. https://doi.org/10.1029/2021GC009812

Katsumata, K., & Nakatani, M. (2021). Testing the seismic quiescence hypothesis through retrospective trials of alarm-based earthquake prediction in the Kurile–Japan subduction zone. Earth, Planets and Space, 73, 100. https://doi.org/10.1186/s40623-021-01418-z

Lowrie, W. (2007). Fundamental of Geophysics (Second). Cambridge University Press. https://doi.org/10.1017/CBO9780511807107 I

Lupi, M., De Gori, P., Valoroso, L., Baccheschi, P., Minetto, R., & Mazzini, A. (2022). Northward migration of the Javanese volcanic arc along thrust faults. Earth and Planetary Science Letters, 577, 117258. https://doi.org/10.1016/j.epsl.2021.117258

Maiti, S. K., & Kim, B. (2025). An Updated, Homogeneous, and Declustered Earthquake Catalog for South Korea and Neighboring Regions. Natural Hazards and Earth System Sciences [preprint], 1–34. https://nhess.copernicus.org/preprints/nhess-2024-197/

Megawati, M., Ma, K.-F., Chen, P.-F., Sianipar, D., & Hsieh, M.-C. (2024). Source characterization of Intermediate-Depth earthquakes in southern Java, Indonesia. Journal of Asian Earth Sciences, 264(128), 106040. https://doi.org/10.1016/j.jseaes.2024.106040

Menke, K. (2022). Discover QGIS 3.x (2nd Editio). Locate Press.

Ministry of Energy and Mineral Resources. (2025). MAGMA Indonesia. https://magma.esdm.go.id/

Mukti, M. M. (2018). Structural complexity in the boundary of forearc basin – accretionary wedge in the northwesternmost Sunda active margin. Bulletin of the Marine Geology, 33(1), 1–14. https://doi.org/10.32693/bomg.33.1.2018.536

Munandar, R. A., & Sulsaladin, R. (2022). Karakteristik Tektonik dan Periode Ulang Gempabumi pada Sesar Cimandiri Jawa Barat. Buletin Metorologi, Klimatologi, Dan Geofisika, 2(4), 42–51. https://balai2bmkg.id/index.php/buletin_mkg/article/view/30

Muttaqy, F., Nugraha, A. D., Mori, J., Puspito, N. T., Supendi, P., & Rohadi, S. (2022). Seismic Imaging of Lithospheric Structure Beneath Central-East Java Region, Indonesia: Relation to Recent Earthquakes. Frontiers in Earth Science, 10, 756806. https://doi.org/10.3389/feart.2022.756806

Noda, A. (2016). Forearc basins: Types, geometries, and relationships to subduction zone dynamics. Bulletin of the Geological Society of America, 128(5–6), 879–895. https://doi.org/10.1130/B31345.1

Pakiding, A., Maulana, A., & Azikin, B. (2025). Analysis of a-Value and b-value parameters for earthquake disaster mitigation around the Saddang Fault. IOP Conference Series: Earth and Environmental Science, 1462(1), 012041. https://doi.org/10.1088/1755-1315/1462/1/012041

Pasari, S., Simanjuntak, A. V. H., Mehta, A., Neha, N, & Sharma, Y. (2021). The Current State of Earthquake Potential on Java Island, Indonesia. Pure and Applied Geophysics, 178(8), 2789–2806. https://doi.org/10.1007/s00024-021-02781-4

Patria, A., & Aulia, A. N. (2020). Structural And Earthquake Evaluations Along Java Subduction Zone, Indonesia. RISET Geologi Dan Pertambangan, 30(1), 65–79. https://jrisetgeotam.brin.go.id/index.php/jrisgeotam/article/view/1072

Pratap, R. (2010). Getting Started with MATLAB A Quick Introduction for Scientists and Engineers.

Pusat Studi Gema Nasional (PuSGeN). (2022). Peta Deagregasi Bahaya Gempa Indonesia. https://sitaba.pu.go.id/user/file/2024_12_19_02_22_36.909104_file.pdf

Putra, F. P., Apriliani, E., & Handoko, E. Y. (2019). Estimation the Height of Tsunami Waves in the Southern Island of Java Using Ensemble Kalman Filter Method. Proceedings of the International Conference on Electrical Engineering and Informatics, 477–482. https://doi.org/10.1109/ICEEI47359.2019.8988859

Rakuasa, H., & Pakniany, Y. (2024). Assessing the Probability of Megathrust Earthquakes in Indonesia : A Review of Seismic Hazard Assessment and Mitigation Strategies. Journal of Loomingulisus Ja Innovatsioon, 1(3), 98–116. https://journal.ypidathu.or.id/index.php/innovatsioon/article/view/1275

Rehman, A., & Zhang, H. (2024). Seismicity and return period investigation of destructive earthquake in Makran subduction zone. Discover Geoscience, 2, 40. https://doi.org/10.1007/s44288-024-00047-9

Sandhu, M., Yadav, R. B. S., Kumar, R., Baruah, S., Singh, A. P., Mishra, M., & Yadav, J. S. (2022). Spatial variability of earthquake hazard parameters, return periods and probabilities of earthquake occurrences in the eastern Himalayan seismic belt. Physics and Chemistry of the Earth Parts A/B/C, 127, 103194. https://doi.org/10.1016/j.pce.2022.103194

Scholl, D. W., Kirby, S. H., von Huene, R., Ryan, H., Wells, R. E., & Geist, E. L. (2015). Great (≥Mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor. Geosphere, 11(2), 236–265. https://doi.org/10.1130/GES01079.1

Siregar, U. K., Sirait, R., & Lubis, L. H. (2023). Identifikasi Tingkat Kerapuhan Batuan (b-Value) dengan Menggunakan Metode Likelihood di Wilayah Sumatera Utara Periode 1990-2021. Jurnal Kumparan Fisika, 6(1), 37–46. https://doi.org/10.33369/jkf.6.1.37-46

Sribudiyani, S., Prasetya, I., Muchsin, N., Sapiie, B., Ryacudu, R., Asikin, S., Kunto, T., Harsolumakso, A. H., Astono, P., & Yulianto, I. (2003). The collision of east java microplate and its implication for hydrocarbon occurences in the east Java basin. Proceesdings, Indonesian Petroleum Association, Twenty-Ninth Annual Convention & Exhibition October 2003. https://www.researchgate.net/publication/285848798

Soehaimi, A., Sopyan, Y., Ma’mur, M., & Agustin, F. (2021). Active Fault Map of Indonesia (Peta Patahan Aktif Indonesia). Directorate of Settlement and Housing Engineering Development Directorate General of Human Settlements Ministry of Public Works and Public Housing. https://geologi.esdm.go.id/geomap/pages/preview/peta-patahan-aktif-indonesia.

Suwandi, E. A., Sari, I. L., & Waslaluddin, W. (2017). Analisis Percepatan Tanah Maksimum, Intensitas Maksimum Dan Periode Ulang Gempa Untuk Menentukan Tingkat Kerentanan Seismik di Jawa Barat (Periode Data Gempa Tahun 1974-2016). Wahana Fisika, 2(2), 78–96. https://doi.org/10.17509/wafi.v2i2.9371

Taroni, M., Vocalelli, G., & De Polis, A. (2021). Gutenberg–Richter B-Value Time Series Forecasting: A Weighted Likelihood Approach. Forecasting, 3(3), 561–569. https://doi.org/10.3390/forecast3030035

Utsu, T. (1966). A Statistical Significance Test of the Difference in b-value Between Two Earthquake Group. Journal of Physics of The Earth, 14(2), 37–40. https://doi.org/10.4294/jpe1952.14.37

van Zelst, I., Rannabauer, L., Gabriel, A. -A., & van Dinther, Y. (2022). Earthquake Rupture on Multiple Splay Faults and Its Effect on Tsunamis. Journal of Geophysical Research: Solid Earth, 127(8), e2022JB024300. https://doi.org/10.1029/2022JB024300

Wessel, P., Luis, J. F., Uieda, L., Scharroo, R., Wobbe, F., Smith, W. H. F., & Tian, D. (2019). The Generic Mapping Tools Version 6. Geochemistry, Geophysics, Geosystems, 20(11), 5556–5564. https://doi.org/10.1029/2019GC008515

Wetzler, N., Lay, T., Brodsky, E. E., & Kanamori, H. (2017). Rupture-Depth-Varying Seismicity Patterns for Major and Great (Mw ≥ 7.0) Megathrust Earthquakes. Geophysical Research Letters, 44(19), 9663–9671. https://doi.org/10.1002/2017GL074573

Wickham-Piotrowski, A., Font, Y., Regnier, M., Delouis, B., Nocquet, J. M., De Barros, L., Durand, V., Bletery, Q., & Segovia, M. (2024). Intraslab seismicity migration simultaneously with an interface slow slip event along the Ecuadorian subduction zone. Tectonophysics, 883, 230365. https://doi.org/10.1016/j.tecto.2024.230365

Widagdo, A., Pramumijoyo, S., & Harijoko, A. (2018). Morphotectono-volcanic of Tertiary volcanic rock in Kulon Progo mountains area, Yogyakarta-Indonesia. IOP Conference Series: Earth and Environmental Science, 212(1), 012051. https://doi.org/10.1088/1755-1315/212/1/012051

Widiyantoro, S., Gunawan, E., Muhari, A., Rawlinson, N., Mori, J., Hanifa, N. R., Susilo, S., Supendi, P., Shiddiqi, H. A., Nugraha, A. D., & Putra, H. E. (2020). Implications for megathrust earthquakes and tsunamis from seismic gaps south of Java Indonesia. Scientific Reports, 10, 1–11. https://doi.org/10.1038/s41598-020-72142-z

Wyss, M., Wiemer, S., & Zúñiga, R. (2001). ZMAP A Tool For Analyses of Seismicity Patterns Typical Applications and Uses : A Cookbook.

Xia, Y., Geersen, J., Klaeschen, D., Ma, B., Lange, D., Riedel, M., Schnabel, M., & Kopp, H. (2021). Marine forearc structure of eastern Java and its role in the 1994 Java tsunami earthquake. Solid Earth, 12(11), 2467–2477. https://doi.org/10.5194/se-12-2467-2021

Xie, F., Wang, Z., Zhao, D., Gao, R., & Chen, X. (2023). Seismic imaging of the Java subduction zone: New insight into arc volcanism and seismogenesis. Tectonophysics, 854, 229810. https://doi.org/10.1016/j.tecto.2023.229810

Zaliapin, I., & Ben-Zion, Y. (2020). Earthquake Declustering Using the Nearest-Neighbor Approach in Space-Time-Magnitude Domain. Journal of Geophysical Research: Solid Earth, 125(4), e2018JB017120. https://doi.org/10.1029/2018JB017120

Zhou, P., & Xia, S. (2020). Effects of the heterogeneous subducting plate on seismicity: Constraints from b-values in the Andaman–Sumatra–Java subduction zone. Physics of the Earth and Planetary Interiors, 304, 106499. https://doi.org/10.1016/j.pepi.2020.106499

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2025-10-01

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Putri, D. M., Maharani, N., Ilham, I., & Yulinda, R. (2025). Spatial Analysis of the Seismic Gap Zone Based on Multiparameter Seismotectonics in Southern East Java as an Indicator of Megathrust Earthquake Potential. JURNAL GEOCELEBES, 9(2), 139–156. https://doi.org/10.70561/geocelebes.v9i2.44633

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Vol. 9 No. 2: October 2025

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