Current Research
SHALLOW (NEAR TRENCH) SUBDUCTION ZONE MECHANICS
Fall 2024
I am a science party member of the 2024 JTRACK IODP Exp. 405. I will be conducting visual core descriptions of sedimentary sequences recovered from the Japan Trench subduction zone plate boundary and accretionary prism. My work includes identifying and interpreting in-situ macro scale faults and folds, and collaborating with other science party members to generate a 3D fault model of the overriding plate in the vicinity of the deep-sea boreholes.
Fall 2022 - ongoing
I am currently working on understanding the seismic and tsunamigenic potential of shallow (near-trench) subduction zones. I use a combination of geophysical surveys, tectonogeomorphic mapping, and structural analysis of the downgoing plate, accretionary prism, and forearc in the Japan Trench and Aleutian subduction zone. My main interests involve understanding what structures, stress regimes, fluid processes, sedimentology, and the frictional processes that either restrict or permit the propagation of rupture to reach shallow plate interfaces.
I am a science party member of the 2024 JTRACK IODP Exp. 405. I will be conducting visual core descriptions of sedimentary sequences recovered from the Japan Trench subduction zone plate boundary and accretionary prism. My work includes identifying and interpreting in-situ macro scale faults and folds, and collaborating with other science party members to generate a 3D fault model of the overriding plate in the vicinity of the deep-sea boreholes.
Fall 2022 - ongoing
I am currently working on understanding the seismic and tsunamigenic potential of shallow (near-trench) subduction zones. I use a combination of geophysical surveys, tectonogeomorphic mapping, and structural analysis of the downgoing plate, accretionary prism, and forearc in the Japan Trench and Aleutian subduction zone. My main interests involve understanding what structures, stress regimes, fluid processes, sedimentology, and the frictional processes that either restrict or permit the propagation of rupture to reach shallow plate interfaces.
Past Projects
PANAMINT VALLEY TRANSFER ZONE, ECSZ
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Fall 2020 - Fall 2022
MS Thesis Research We investigated paleoseismic, late Holocene evidence for multi-fault and complex rupture in Panamint Valley, located ~50 km northeast of the 2019 Ridgecrest ruptures. We produced a 1:4k and 1:12k tectonogeomorphic maps of the 40 km² area between the Ash Hill and Panamint Valley faults. We defined a locally calibrated relative-age alluvial fan chronology to correlate generations of offset Holocene alluvium across large distances. We used NCALM lidar DEMs, aerial imagery, 3D drone-based photogrammetry, and ground truthing to identify ruptures. We bracketed earthquake timing with IRSL dating of offset alluvial deposits. We recorded vertical and lateral offsets at over 250+ locations using field mapping and statistically backslipped reconstructions of offsets from newly-generated high-resolution (5 cm) drone-based structure from motion (SfM) digital surface models. USGS EDMAP I produced a 1:12k scale map of the central Panamint Valley, including a compilation of prior mapping from Regalla et al. (2022) and Sethanant (2019). I employed standardized GeMS mapping techniques and worked with Andy Cyr, the Project Chief for the Neotectonics of the Northern Mojave Desert mapping effort, to produce a professional USGS-style map. This map won second place at the Best Student Geologic Map Competition at GSA 2022. |
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MUSEUM FIRE SEISMIC MONITORING, FLAGSTAFF, AZ
Fall 2020
Wildfires are efficient at slope destabilization through a removal of vegetation and increased hydrophobicity of soil. After the 2019 Museum Fire in Flagstaff, AZ, slope destabilization and summer monsoons contributed to high landslide hazard risk on Mt. Elden. In order to characterize the geophysical signature of the vibration energy produced from mass wasting, seismometers were deployed in the summer of 2019 and the summer of 2020. Under the supervision of Dr. Ryan Porter, I assisted in the monitoring of seismometers in the second field season. I was responsible for the collection and processing of data in the second field season.
Wildfires are efficient at slope destabilization through a removal of vegetation and increased hydrophobicity of soil. After the 2019 Museum Fire in Flagstaff, AZ, slope destabilization and summer monsoons contributed to high landslide hazard risk on Mt. Elden. In order to characterize the geophysical signature of the vibration energy produced from mass wasting, seismometers were deployed in the summer of 2019 and the summer of 2020. Under the supervision of Dr. Ryan Porter, I assisted in the monitoring of seismometers in the second field season. I was responsible for the collection and processing of data in the second field season.
PUBLICATIONS, POSTERS, PRESENTATIONS, Conferences
2025
- LaPlante, A., & Regalla, C, Sethanant, I., Mahan, S., Harrison, G. (2025). Spatiotemporally-variable strain release and seismic rupture in multifault systems: An example from Panamint Valley, southeastern California. [Manuscript in review]. School of Earth and Environmental Science, Northern Arizona University.
- LaPlante, A., & Regalla, C. (2024, 09). Testing the potential for static triggering of Holocene earthquakes on faults in the Panamint and Searles Valleys, northern ECSZ. Poster Presentation at 2024 SCEC Annual Meeting.
- Regalla, C., LaPlante, A., Schottenfels, E., & Nakamura, Y. (2024, 05). Mapping heterogeneity in frontal prism and decollement structure in the Japan Trench in regions that have hosted shallow tsunamigenic slip. Poster Presentation at the 2024 JpGU Annual Meeting.
- Co-convener of AGU2023 session NH004: Advancing Subduction Zone Science: Collaborating Across Borders and Cultures
- LaPlante, A., Regalla, C., Sethanant, I., Mahan, S. A., Gray, H. J. (2022). Quantifying modifications in Holocene alluvial fan morphology to determine paleoseismicity of the Panamint Valley transtensional relay (ECSZ). Oral Presentation at 2022 GSA Connects Annual Meeting.
- LaPlante, A., Regalla, C. (2022) Quaternary surficial mapping of central Panamint Valley to evaluate paleoseismic evidence for multi-fault rupture, Eastern California Shear Zone. Poster Presentation at 2022 GSA Connects Annual Meeting.
- LaPlante, A. A. (2022). Evidence for late Holocene multi-fault rupture in the Panamint Valley transtensional relay, eastern California shear zone (Order No. 29322818). [Masters thesis, Northern Arizona University, 148 pp.] Available from ProQuest Dissertations & Theses Global. (2705435966).
- LaPlante, A., Regalla, C., & Sethanant, I. (2022, 09). Evidence for late Holocene multi-fault rupture in the Panamint Valley transtensional relay, Eastern California Shear Zone (ECSZ). Poster Presentation at 2022 SCEC Annual Meeting.
- Regalla, C., Kirby, E., Mahan, S., McDonald, E., Pangrcic, H., Binkley, A., Schottenfels, E., LaPlante, A., Sethanant, I., & Lynch, E. M. (2022). Late Holocene rupture history of the Ash Hill fault, Eastern California Shear Zone, and the potential for seismogenic strain transfer between nearby faults. Earth Surface Processes and Landforms. https://doi.org/10.1002/esp.5432
- LaPlante, A., & Regalla, C. (2021, 08). Tectonogeomorphic evidence for late Holocene complex rupture linking the Panamint Valley and Ash Hill faults, Eastern California Shear Zone. Poster Presentation at 2021 SCEC Annual Meeting.
- Porter, R., Joyal, T., Beers, R., Loverich, J., LaPlante, A., Spruell, J., Youberg, A., Schenk, E., Robichaud, P. R., & Springer, A. E. (2021). Seismic Monitoring of Post-wildfire Debris Flows Following the 2019 Museum Fire, Arizona. Frontiers in Earth Science, 9, [649938]. https://doi.org/10.3389/feart.2021.649938
