EARTHQUAKE DEPTH PREDICTION IN THE HIMALAYAS USING ENSEMBLE MACHINE LEARNING
DOI:
https://doi.org/10.3126/jist.v31i1.92728Keywords:
Central Himalaya, Depth prediction, Machine learning, Random Forest, SeismotectonicAbstract
This study assesses the potential of ensemble ML methods for earthquake focal depth prediction in the Central Himalaya. The basic catalog parameters (time, location, magnitude) are used from 1964-2024. Four regression models - Decision Tree, Bagging, Random Forest, and Tuned Random Forest were evaluated using a train-test split. Using ensemble methods, tree over fitting was substantially reduced compared to a single Decision Tree (test R² improved from 0.112 to 0.425). However, all R² values remained low that indicating limited overall predictive capability. Specifically, the tuned Random Forest achieved the highest test R² of 0.425. Despite this improvement, all models had a systematic bias of predicting depths shallower than the actual depths and under predicting the events below 80 km reflecting the bimodal seismicity of the region and the different tectonics processes governing crustal and lithospheric earthquakes. The results of the study indicate that catalog parameters alone are not sufficient for reliable depth prediction in this tectonically complex setting. To achieve any meaningful improvement, geophysical variables including crustal thickness, fault geometry and heat flow must be incorporated. Moreover, crustal and mantle seismicity should be modelled separately using a stratified approach.
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Ader, T., Avouac, J., Liu‐Zeng, J., Lyon‐Caen, H., Bollinger, L., Galetzka, J., Genrich, J., Thomas, M., Chanard, K., Sapkota, S. N., Rajaure, S., Shrestha, P., Ding, L., & Flouzat, M. (2012). Convergence rate across the Nepal Himalaya and interseismic coupling on the Main Himalayan Thrust: Implications for seismic hazard. Journal of Geophysical Research: Solid Earth, 117(B4), 1–16. https://doi.org/10.1029/2011JB009071
Allen, T. I., Wald, D. J., & Worden, C. B. (2012). Intensity attenuation for active crustal regions. Journal of Seismology, 16(3), 409–433. https://doi.org/10.1007/s10950-012-9278-7
Aryal, M., Tiwari, R. K., & Paudyal, H. (2024). Prediction of Earthquakes in Nepal and the Adjoining Regions Using LSTM. BMC Journal of Scientific Research, 7(1), 12–26. https://doi.org/10.3126/bmcjsr.v7i1.73058
Avouac, J. P. (2003). Mountain Building, Erosion, and the Seismic Cycle in the Nepal Himalaya. Advances in Geophysics, 46, 1–80. https://doi.org/10.1016/S0065-2687(03)46001-9
Bai, L., Li, G., Khan, N. G., Zhao, J., & Ding, L. (2017). Focal depths and mechanisms of shallow earthquakes in the Himalayan–Tibetan region. Gondwana Research, 41, 390–399. https://doi.org/10.1016/j.gr.2015.07.009
Belgiu, M., & Drăgu, L. (2016). Random forest in remote sensing: A review of applications and future directions. ISPRS Journal of Photogrammetry and Remote Sensing, 114, 24–31. https://doi.org/10.1016/j.isprsjprs.2016.01.011
Bergstra, J., & Bengio, Y. (2012). Random Search for Hyper-Parameter Optimization. Journal of Machine Learning Research, 13, 281–305.
Bilham, R. (2004). Earthquakes in India and the Himalaya: tectonics, geodesy and history. Annals of Geophysics, 47(2–3), 839–858. https://doi.org/10.4401/ag-3338
Bollinger, L., Sapkota, S. N., Tapponnier, P., Klinger, Y., Rizza, M., Woerd, J. Van Der, Tiwari, D. R., Pandey, R., Bitri, A., & Berc, S. B. De. (2014). Estimating the return times of great Himalayan earthquakes in eastern Nepal: Evidence from the Patu and Bardibas strands of the Main Frontal Thrust. Journal of Geophysical Research : Solid Earth of the Main Frontal Thrust, 119, 7123–7163. https://doi.org/10.1002/2014JB010970
Breiman, L. (1996). Bagging predictors. Machine Learning, 24(2), 123–140. https://doi.org/10.1007/bf00058655
Breiman, L. (2001). Random Forests. Machine Learning, 45, 5–32.
Breiman, L., Friedman, J., Stone, C. J., & Olshen, R. A. (1984). Classification and regression trees. Chapman & Hall.
Cattin, R., & Avouac, J. P. (2000). Modeling mountain building and the seismic cycle in the Himalaya of Nepal. Journal of Geophysical Research: Solid Earth, 105(B6), 13389–13407. https://doi.org/10.1029/2000JB900032
Hastie, T., Tibshirani, R., & Friedman, J. (2009). The Elements of Statistical Learning: Data Mining, Inference, and Prediction, Second Edition (Springer Series in Statistics).
Houston, H. (2015). Deep Earthquakes. In Treatise on Geophysics: Second Edition (Vol. 4). Elsevier B.V. https://doi.org/10.1016/B978-0-444-53802-4.00079-8
Jackson, J., McKenzie, D., Priestley, K., & Emmerson, B. (2008). New views on the structure and rheology of the lithosphere. Journal of the Geological Society, 165(2), 453–465. https://doi.org/10.1144/0016-76492007-109
James, G., Witten, D., Hastie, T., & Tibshirani, R. (2021). An Introduction to Statistical Learning. In G. Allen, R. De Veaux, & R. Nugent (Eds.), Current Medicinal Chemistry (2nd Editio). Springer US. https://doi.org/10.1007/978-1-0716-1418-1
Kanamori, H. (1977). The energy release in great earthquakes. Journal of Geophysical Research, 82(20), 2981–2987. https://doi.org/10.1029/jb082i020p02981
Kanamori, H., & Brodsky, E. E. (2004). The physics of earthquakes. Reports on Progress in Physics, 67(8), 1429. https://doi.org/10.1088/0034-4885/67/8/R03
Kayal, J. R., & Hazarika, D. (2025). Recent Large Earthquakes in the Eastern Himalaya and its Foredeep Region: Seismotectonic Appraisal. Journal of the Geological Society of India, 101(6), 776–781. https://doi.org/10.17491/jgsi/2025/174159
Kumar, S., Wesnousky, S. G., Rockwell, T. K., Briggs, R. W., Thakur, V. C., & Jayangondaperumal, R. (2006). Paleoseismic evidence of great surface rupture earthquakes along the Indian Himalaya. Journal of Geophysical Research: Solid Earth, 111(3). https://doi.org/10.1029/2004JB003309
Lay, T., & Wallace, T. C. (1995). Modern Global Seismology (Vol. 58).
Molnar, P., & Tapponnier, P. (1975). Cenozoic Tectonics of Asia: Effects of a Continental Collision: Features of recent continental tectonics in Asia can be interpreted as results of the India-Eurasia collision. Science, 189(4201), 419–426. https://doi.org/10.1126/science.189.4201.419
Molnar, P., & Wang-ping, C. (1983). Focal depths and fault plane solution of earthquakes under the Tibet Plateau. Journal of Geophysical Research, 88(B2), 1180–1196. https://doi.org/10.1029/JB088iB02p01180
Mousavi, S. M., Ellsworth, W. L., Zhu, W., Chuang, L. Y., & Beroza, G. C. (2020). Earthquake transformer—an attentive deep-learning model for simultaneous earthquake detection and phase picking. Nature Communications, 11(1), 1–12. https://doi.org/10.1038/s41467-020-17591-w
Münchmeyer, J., Saul, J., & Tilmann, F. (2024). Learning the Deep and the Shallow: Deep-Learning-Based Depth Phase Picking and Earthquake Depth Estimation. Seismological Research Letters, 95(3), 1543–1557. https://doi.org/10.1785/0220230187
Ni, J. F. (1989). Active Tectonics of the Himalaya. Journal of Earth System Science, 98(1), 71–89. https://doi.org/10.1007/BF02880377
Pandey, M. R., Tandukar, R. P., Avouac, J. P., Vergne, J., & Heritier, T. (1999). Seismotectonics of the Nepal Himalaya from a local seismic network. Journal of Asian Earth Sciences, 17(5), 703–712. https://doi.org/10.1016/S1367-9120(99)00034-6
Reasenberg, P. (1985). Second‐order moment of central California seismicity, 1969–1982. Journal of Geophysical Research: Solid Earth, 90(B7), 5479–5495. https://doi.org/10.1029/JB090iB07p05479
Richter, C. F. (1935). An instrumental earthquake magnitude scale. Bulletin of the Seismological Society of America, 25(1), 1–32. https://doi.org/10.1086/622062
Shearer, P. M. (2019). Introduction to seismology. Cambridge university press.
Stevens, V. L., & Avouac, J. P. (2015). Interseismic coupling on the main Himalayan thrust. Geophysical Research Letters, 42, 5828–5837. https://doi.org/10.1002/2015GL064845
Subedi, A., Parajuli, D., Thapa, M., Sigdel, D., Bogati, S., Subedi, T., Tiwari, R. K., & Paudyal, H. (2025). Probabilistic Seismic Hazard Assessment Using Gumbel’s Extreme Value Distribution in the Himalayan Arc (71.6°E – 97°E and 37.5°N – 26.6°N). BMC Journal of Scientific Research, 8(1), 18–29. https://doi.org/10.3126/bmcjsr.v8i1.87892
Tiwari, R. K., & Paudyal, H. (2021). Seismic phases of 25 April 2015 (Mw 7.8) Earthquake and 12 May 2015 (Mw 7.3) Earthquake Predicted by AK135 Model - A comparison. Journal of Nepal Physical Society, 7(2), 58–64. https://doi.org/10.3126/jnphyssoc.v7i2.38623
Tiwari, R. K., & Paudyal, H. (2024). b-value Estimation and Extreme Magnitude Assessment in the Source Region of Past Earthquakes in Central Himalaya and Vicinity. Jordan Journal of Earth and Environmental Sciences, 15(3), 183–191.
Tiwari, R. K., Poudel, R. P., & Paudyal, H. (2025). Machine learning for predicting earthquake magnitudes in the Central Himalaya. BIBECHANA, 22(1), 22–29. https://doi.org/10.3126/bibechana.v22i1.70637
Tiwari, R. K., Subedi, A., Parajuli, D., Dharel, S., Neupane, A., Subedi, H., Timsina, B. R., & Paudyal, H. (2025). Regional patterns of seismic b-values variations in the Himalayan region (71.6°E – 95.5°E and 37.5°N – 26.6°N). Journal of Seismic Exploration, 34(1), 1–11. https://doi.org/10.36922/JSE025210006
Willemann, R. J., & Storchak, D. A. (2001). Data collection at the International Seismological Centre. Seismological Research Letters, 72(4), 440–453. https://doi.org/10.1785/gssrl.72.4.440
Woessner, J., & Wiemer, S. (2005). Assessing the Quality of Earthquake Catalogues : Estimating the Magnitude of Completeness and Its Uncertainty. Bulletin of the Seismological Society of America, 95(2), 684–698. https://doi.org/10.1785/0120040007
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