About
Osamu SANDANBATA | Assistant Professor, Earthquake Research Institute, the University of Tokyo.
[ email / cv / Google Scholar/ researchmap / ORCID / ResearchGate ]
Research
statements. My research primarily uses tsunami observations to investigate volcanic, earthquake, and other geophysical processes occurring at and beneath the seafloor—this is what I call Tsuanmi Volcanology and Seismology. Tsunamis provide valuable information on the mechanisms and spatiotemporal evolution of their sources, which are often difficult to observe directly beneath the ocean. Tsunami observations, however, capture only one aspect of these source processes. A more complete understanding requires integrating seismic and hydroacoustic waves, earthquake rupture processes, and volcanic deformation. I therefore combine observations and modeling of tsunamis, earthquakes, and volcanoes to understand these processes from multiple physical perspectives. I also study tsunami phenomena themselves, including their generation and propagation.
topics. My research topics includes the followings:
1) tsunami volcanology & seismology. Tsunami phenomena associated with submarine volcanoes and earthquakes, including trapdoor faulting in submarine calderas, underwater eruptions, and underwater earthquakes.
2) seismic waveform analysis. Seismic waveform analysis to investigate source processes, including centroid-moment-tensor analysis, forward modeling, and repeating-event analysis.
3) earthquake and volcano modeling. Physical and numerical modeling of tsunamis, and earthquake and volcanic source processes.
4) general tsunami science. Tsunami generation, propagation, and coastal impacts, including hazard forecasting and assessment.
Opportunities
for graduate students. I can co-supervise graduate students in the master’s and doctoral-degree programs at the Department of Earth and Planetary Science (EPS), The University of Tokyo, working alongside a primary supervisor. My collaborators in related fields at ERI include Profs. Shingo Watada (earth & planetary dynamics), Shusuke Takemura (seismology), and Mie Ichihara (volcanology). Please contact me to discuss potential research topics and supervision arrangements.
for visiting students. I host internship students through funded programs:
1) UTRIP (6 weeks for undergraduate students)
2) JST Sakura Science Program (3 weeks for graduate and undergraduate students).
for post-docs. Funding opportunities for postdoctoral researchers include:
1) ERI Visiting Program for Post-doc Researchers (2 years)
2) JSPS Postdoctoral Fellowship for Research in Japan (Standard) (1–2 years)
for visitors. Funding opportunities for visiting researchers include:
1) ERI Visiting Program for Visiting Researchers (2–6 months)
2) JSPS Invitational Fellowships (Long-term: 2–10 months; Short-term: 14–60 days)
Self-funded visits are also welcome. For more details, please see the ERI international page.
Publications
submitted papers.
[-] Okuwaki, R., Fan, W., Sandanbata, O., Roman, D. C., & Fialko, Y. (under review). The explosive engine of the 2022 Hunga submarine eruption. https://eartharxiv.org/repository/view/14897/
peer-reviewed papers.
[19] Sandanbata, O., & Takemura, S. (2025). Full‐spectrum similarity of repeating trapdoor faulting. Geophysical Research Letters, 52(24), e2025GL119615. https://doi.org/10.1029/2025gl119615 [Summary]
[18] Sandanbata, O., & Saito, T. (2024b). Segmented Trapdoor Fault in Kita-Ioto Caldera, Japan: Insights From Millimeter Tsunami Waves Captured by an Array Network of Ocean Bottom Pressure Gauges. Journal of Geophysical Research: Solid Earth, 129(12), e2024JB029755. https://doi.org/10.1029/2024JB029755 [Summary]
[17] Takemura, S., Kubota, T., & Sandanbata, O. (2024). Successive tsunamigenic events near Sofu Seamount inferred from high-frequency teleseismic P and regional T waves. Journal of Geophysical Research: Solid Earth, 129, e2024JB029746. https://doi.org/10.1029/2024JB029746 [Summary]
[16] Kubota, T., Sandanbata, O., Saito, T., & Matsuzawa, T. (2024). Accelerating seafloor uplift of submarine caldera near Sofugan volcano, Japan, resolved by distant tsunami recordings. Geophysical Research Letters, 51(12). https://doi.org/10.1029/2024gl108415
[15] Sandanbata, O., Satake, K., Takemura, S., Watada, S., Maeda, T., & Kubota, T. (2024). Enigmatic tsunami waves amplified by repetitive source events near Sofugan volcano, Japan. Geophysical Research Letters, 51, e2023GL106949. https://doi.org/10.1029/2023GL106949
[14] Sandanbata, O., & Saito, T. (2024a). Quantifying magma overpressure beneath a submarine caldera: A mechanical modeling approach to tsunamigenic trapdoor faulting near Kita-Ioto Island, Japan. Journal of Geophysical Research: Solid Earth, 129, e2023JB027917. https://doi.org/10.1029/2023JB027917 [Summary]
[13] Sandanbata, O., Watada, S., Satake, K., Kanamori, H., & Rivera, L. (2023). Two volcanic tsunami events caused by trapdoor faulting at a submerged caldera near Curtis and Cheeseman Islands in the Kermadec Arc. Geophysical Research Letters, 50, e2022GL101086. https://doi.org/10.1029/2022GL101086
[12] Sandanbata, O., Watada, S., Satake, K., Kanamori, H., Rivera, L., & Zhan, Z. (2022). Sub-decadal volcanic tsunamis due to submarine trapdoor faulting at Sumisu caldera in the Izu–Bonin Arc. Journal of Geophysical Research: Solid Earth, 127, e2022JB024213. https://doi.org/10.1029/2022JB024213 [Summary]
[11] Kubo, H., Kubota, T., Suzuki, W., Aoi, S., Sandanbata, O., Chikasada, N., & Ueda, H. (2022). Ocean-wave phenomenon around Japan due to the 2022 Tonga eruption observed by the wide and dense ocean-bottom pressure gauge networks. Earth Planets Space, 74, 104. https://doi.org/10.1186/s40623-022-01663-w
[10] Kubota, T., Saito, T., Chikasada, N. Y., & Sandanbata, O. (2021). Meteotsunami observed by the deep-ocean seafloor pressure gauge network off northeastern Japan, Geophysical Research Letters, 48(21) e2021GL094255. https://doi.org/10.1029/2021GL094255
[9] Lai, V. H., Zhan, Z., Brissaud, Q., Sandanbata, O., & Miller, M. S. (2021). Inflation and Asymmetric Collapse at Kilauea Summit during the 2018 Eruption from Seismic and Infrasound Analyses, Journal of Geophysical Research: Solid Earth, 126(10), e2021JB022139. https://doi.org/10.1029/2021JB022139
[8] Sandanbata, O., Kanamori, H., Rivera, L., Zhan, Z., Watada, S., & Satake, K. (2021). Moment tensors of ring-faulting at active volcanoes: Insights into vertical-CLVD earthquakes at the Sierra Negra caldera, Galápagos Islands, Journal of Geophysical Research: Solid Earth, 126(6), e2021JB021693. https://doi.org/10.1029/2021JB021693
[7] Sandanbata, O., Watada, S., Ho, T-C., & Satake, K. (2021). Phase delay of short-period tsunamis in the density-stratified compressible ocean over the elastic Earth, Geophysical Journal International, 226(3), 1975–1985. https://doi.org/10.1093/gji/ggab192
[6] Saito, T., Kubota, T., Chikasada, N. Y., Tanaka, Y., & Sandanbata, O. (2021). Meteorological tsunami generation due to sea-surface pressure change: Three-dimensional theory and synthetics of ocean-bottom pressure change, Journal of Geophysical Research: Oceans, 126(5), e2020JC017011. https://doi.org/10.1029/2020JC017011
[5] Heidarzadeh, M., Ishibe, T., Sandanbata O., Muhari, A., & Wijanarto, A. B. (2020). Numerical modeling of the subaerial landslide source of the 22 December 2018 Anak Krakatoa volcanic tsunami, Indonesia, Ocean Engineering, 195, 106733. https://doi.org/10.1016/j.oceaneng.2019.106733
[4] Wang, Y., Satake, K., Sandanbata, O., Maeda, T., & Su, H. (2019). Tsunami data assimilation of cabled ocean bottom pressure records for the 2015 torishima volcanic tsunami earthquake, Journal of Geophysical Research: Solid Earth, 124(10), 10413-10422. https://doi.org/10.1029/2019JB018056
[3] Sandanbata, O., Watada, S., Satake, K., Fukao, Y., Sugioka, H., Ito, A., & Shiobara, H. (2018). Ray Tracing for Dispersive Tsunamis and Source Amplitude Estimation Based on Green’s Law: Application to the 2015 Volcanic Tsunami Earthquake Near Torishima, South of Japan, Pure and Applied Geophysics, 175, 1371–1385. https://doi.org/10.1007/s00024-017-1746-0
[2] Fukao, Y., Sandanbata, O., Sugioka, H., Ito, A., Shiobara, H., Watada, S., & Satake, K. (2018). Mechanism of the 2015 volcanic tsunami earthquake near Torishima, Japan. Science Advances, 4(4), eaao0219. https://doi.org/10.1126/sciadv.aao0219
[1] Sandanbata, O., Obara, K., Maeda, T., Takagi, R., & Satake, K. (2015). Sudden changes in the amplitude‐frequency distribution of long‐period tremors at Aso volcano, southwest Japan, Geophysical Research Letters, 42, 10,256–10,262. https://doi.org/10.1002/2015GL066443