Data Services Products: EMC-AlaskaPeninsula_Vp_Vp/Vs_2025 Slab morphology, dehydration, and sub-arc melting beneath the Alaska Peninsula revealed by body-wave tomography

Summary

This study presents two seismic models of the Alaska Peninsula at different scales: 3D dVp model extending to 660 km depth, constrained by both teleseismic and regional arrival times using teleseismic double-difference tomography (teletomoDD). The second model presents 3D Vp and Vp/Vs structures extending to 200 km depth, constrained by regional arrival times using regional-scale double-difference tomography (tomoDD).

Description

Name AlaskaPeninsula_Vp_Vp/Vs_2025
Title Slab morphology, dehydration, and sub-arc melting beneath the Alaska Peninsula revealed by body-wave tomography
Type 3-D Tomography Earth model
Sub Type Body-wave velocity (km/s) and compressional wave to shear wave velocity ratio
Year 2025
Data Revision r0.0 (revision history)
 
Short Description   This study presents two seismic models of the Alaska Peninsula at different scales: 3D dVp model extending to 660 km depth, constrained by both teleseismic and regional arrival times using teleseismic double-difference tomography (teletomoDD). The second model presents 3D Vp and Vp/Vs structures extending to 200 km depth, constrained by regional arrival times using regional-scale double-difference tomography (tomoDD).
 
Authors: Fan Wang, Department of Earth and Environmental Sciences, University of Michigan, Ann Abor, MI, 48109, USA

S. Shawn Wei, Department of Earth and Environmental Sciences, Michigan State University, East Lansing, 48824, USA
 
Reference Model Ak135-f
 
Prior Model None
 
Model Download Alaska-Vp-deep.r0.0.nc (see metadata) is the seismic 3D dVp model (reference to 1D Ak135-f model) that extends to 660 km depth in netCDF 3 Classic format.


Alaska-Vp-VpVs.r0.0.nc (see metadata) is the 3D Vp and Vp/Vs model that extends to 200 km depth in netCDF 3 Classic format.
 
Model Home Page None
 
Depth Coverage 3D dVp model extends from 0 to 660 km reference to global Ak135-f model, 3D Vp and Vp/Vs models extend from 0 to 200 km
 
Area The Alaska Peninsula (3D dVp model extending to 660 km: longitude: -170°E/-145°E, latitude: 51°N/63°N) (3D Vp and Vp/ Vs extending to 200 km: longitude: -164.5°E/-148°E, latitude: 51°N/60.6°N)
 
Data Set Description The 3D dVp model extending to 660 km depth is constrained by both teleseismic and regional arrival-time data. The teleseismic arrival-time dataset consisted of two parts. The first part included arrival-times from Alaska earthquakes recorded by global seismic stations from 2000 to 2020 and reported by the International Seismological Centre. The second part included arrival times from teleseismic events with magnitudes larger than 6 and epicentral distances from 30° to 90° recorded by regional stations from May 2018 through August 2019 from newly acquired the Alaska Amphibious Community Seismic Experiment (AACSE).


The 3D Vp and Vp/Vs extending to 200 km is constrained by P- and S-wave arrival times of local earthquakes from May 2018 through August 2019 recorded by onshore and offshore seismic stations of AACSE, EarthScope USArray, and the Alaska regional network.
 
 

Figure 1
Fig 1. Maps of the large-scale Vp model (a) at 50, 150, 200, 300, 400, 500, and 600 km depths imaged with teletomoDD. Anomalies are referenced to the 1-D Ak135-f model (Kennett, 1995). Bold dark-green lines indicate the cross-sections in Fig. 2. The black curves show the coastlines. The red contours outline 1% of dVp. The thick dashed lines show the boundary between adjacent segments in this study. The gray dashed lines and blue bars illustrate the 5 segments discussed in Wang et al. (2025) (1. Pav: Pavlof segment; 2. Shu: Shumagin segment; 3. Chi: Chignik segment; 4. Chr: Chirikof segment; 5. Kod: Kodiak segment). Low-resolution regions are masked by the hit quality contour of 0.8 (darkgreen contour in Fig. 5 in Wang et al. (2025)).

Figure 2
Fig 2. Large-scale Vp model imaged with teletomoDD along 6 cross-sections in Fig. 1. The black curves show the slab surface geometry based on a model constrained by active-source seismic experiments (Kuehn, 2019) combined with the Slab2 model (Hayes et al., 2018). Black dots indicate the relocated earthquakes. Low-resolution regions are masked by the hit quality contour of 0.8. Topography/bathymetry is plotted on the top of each panel with vertical exaggeration. The segment name, segment number and volcano names are shown atop the topography/bathymetry.

Figure 3
Fig 3. The high-resolution Vp and Vp/Vs structure at the slab surface and 10 km beneath the slab surface imaged with the regional-scale tomoDD. The black dashed lines and blue bars in (a) illustrate the 5 segments discussed in Wang et al. (2025) (Pav: Pavlof segment; Shu: Shumagin segment; Chi: Chignik segment; Chr: Chirikof segment; Kod: Kodiak segment). Bold darkgreen and black lines in (b) indicate the cross-sections in Figs. 4 and 5. Dark yellow contours on the Pacific Plate outline seafloor magnetic anomalies (Meyer et al., 2017). The black curve with ticks indicates the Alaska-Aleutian Trench where the Pacific Plate is subducting into the deep Earth at a convergence rate of 63 mm/yr (Bird, 2003). The magenta curves illustrate the slab surface (top of the plate interface) at 20, 40, 60, 80, and 100 km depths. The slab surface geometry is based on a model constrained by active-source seismic experiments (Kuehn, 2019) combined with the Slab2 model (Hayes et al., 2018). Black dashed contours outline the rupture zones of historical megathrust earthquakes determined from their aftershock distributions (Davies et al., 1981), whereas black solid contours show 1-m slip areas of previous megathrust earthquakes (Elliott et al., 2022; Freymueller et al., 2021; Xiao et al., 2021). Red triangles indicate Holocene volcanoes (Global Volcanism Program, 2024).

Figure 4
Fig 4. Vp model imaged with the regional-scale tomoDD along 6 cross-sections shown in Fig. 3. In each panel, the black curve shows the slab surface based on the Slab2 (Hayes et al., 2018) model combined with the geometry changes constrained by previous active-source seismic studies (Kuehn, 2019), where the gray curve shows the slab Moho. The dark-green and red dashed curves show the bottom of the sediment layer and the overriding plate Moho, respectively, based on an independent surface-wave tomography study (Li et al., 2024). Regions with model semblance values below 0.54 are masked with purple contours in Figs. 11 and 12 of Wang et al. (2025). Thin dashed black contours represent a higher resolvability level of 0.65, indicating areas where the models are most clearly resolved. Topography/bathymetry is plotted on the top of each panel with vertical exaggeration. The relocated earthquake distribution is shown as black dots in each cross-section. The Vp structure above 50 km is plotted relative to the average Vp of the structure above the slab surface at the same depth.

Figure 5
Fig 5. Vp/Vs model imaged with the regional-scale tomoDD along 6 cross-sections shown in Fig. 3. Other features are the same as in Fig. 4.

Citations and DOIs

To cite the original work behind this Earth model:

  • Wang, F., Wei, S. S., Ruppert, N. A., Zhang, H., & Wu, J. (2025). Slab morphology, dehydration, and sub‐arc melting beneath the Alaska Peninsula
    revealed by body‐wave tomography. Journal of Geophysical Research: Solid Earth, 130, e2024JB029814. https://doi.org/10.1029/2024JB029814
  • Wang, F., Wei, S. S., Drooff, C., Elliott, J. L., Freymueller, J. T., Ruppert, N. A., & Zhang, H. (2024). Fluids control along-strike variations in the Alaska megathrust slip. Earth and Planetary Science Letters, 633, 118655. https://doi.org/10.1016/j.epsl.2024.118655

To cite IRIS DMC Data Products effort:

  • Trabant, C., A. R. Hutko, M. Bahavar, R. Karstens, T. Ahern, and R. Aster (2012), Data Products at the IRIS DMC: Stepping Stones for Research and Other Applications, Seismological Research Letters, 83(5), 846–854, https://doi.org/10.1785/0220120032.

DOI for this EMC webpage: https://doi.org/10.17611/dp/emc.2025.alaskapeninsulavpvs2025.1

References

  • Davies, J., Sykes, L., House, L., & Jacob, K. (1981), Shumagin seismic gap, Alaska Peninsula: History of great earthquakes, tectonic setting, and evidence for high seismic potential, J. Geophys. Res., 86(B5), 3821-3855, https://doi.org/10.1029/JB086iB05p03821.
  • Elliott, J. L., Grapenthin, R., Parameswaran, R. M., Xiao, Z., Freymueller, J. T., & Fusso, L. (2022), Cascading rupture of a megathrust, Sci. Adv., 8(18), eabm4131, https://doi.org/10.1126/sciadv.abm4131.
  • Freymueller, J. T., Suleimani, E. N., & Nicolsky, D. J. (2021), Constraints on the slip distribution of the 1938 Mw 8.3 Alaska Peninsula earthquake from tsunami modeling, Geophys. Res. Lett., 48(9), e2021GL092812, https://doi.org/10.1029/2021gl092812.
  • Hayes, G. P., Moore, G. L. P., Portner D. E., Hearne, M. F., Flamme, H., Furtney, M., et al. (2018), Slab2, a comprehensive subduction zone geometry model, Science, 362(6410), 58-61, https://doi.org/10.1126/science.aat4723.
  • Li, Z., Wiens, D. A., Shen, W., & Shillington, D. J. (2024), Along-strike variations of Alaska subduction zone structure and hydration determined from amphibious seismic data, J. Geophys. Res. Solid Earth, e2023JB027800, https://doi.org/10.1029/2023JB027800.
  • Meyer, B., Chulliat, A., & Saltus, R. (2017). Derivation and error analysis of the earth magnetic anomaly grid at 2 arc min resolution version 3 (EMAG2v3). Geochem. Geophys. Geosyst, 18, 4522–4537, doi: https://doi.org/10.1002/2017GC007280
  • Kennett, B. L., Engdahl. R., & Buland, R. (1995), Constraints on seismic velocities in the earth from travel times, Geophys. J. Int, 122(1), 108-124.
  • Kuehn, H. (2019), Along-trench segmentation and down-dip limit of the seismogenic zone at the eastern Alaska-Aleutian subduction zone, 334 pp, Dalhousie University.
  • Wang, F., Wei, S. S., Ruppert, N. A., Zhang, H. J. Wu, J. (2025). Slab morphology, dehydration, and sub-arc melting beneath the Alaska Peninsula revealed by body-wave tomography, Journal of Geophysical Research: Solid Earth (in press)
  • Xiao, Z., Freymueller, J. T., Grapenthin, R., Elliott, J. L., Drooff, C., & Fusso, L. (2021), The deep Shumagin gap filled: Kinematic rupture model and slip budget analysis of the 2020 Mw 7.8 Simeonof earthquake constrained by GNSS, global seismic waveforms, and floating InSAR, Earth Planet. Sci. Lett., 576, 117241, https://doi.org/10.1016/j.epsl.2021.117241.

Credits

  • r0.0 model provided by Fan Wang.

Revision History

revision r0.0: uploaded February 26, 2025.

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