19-13. Seismic imaging of Kilauea Volcano, Hawaii

Background:  

The transformative events at Kilauea volcano in the spring and summer of 2018 resulted in a partial caldera collapse at the summit of the volcano, as outflow of 1.5 km3 of lava occurred in 60 days. This voluminous outflow amounted to 15 years of supply and tapped deep reservoirs between the summit and the lower East Rift Zone (Neal et al., 2019). The collapse altered the geologic structure of the summit. Now, as InSAR and gravity data indicate that magma is refilling the volcano (Poland et al., 2019), we are blind as to the structures that may be activated, particularly at depths between 2 and 7 km below the surface. To address this critical need, we will use controlled active-source seismic surveys utilizing frequencies of 5-25 Hz combined with passive (earthquake or ocean loading ambient noise) seismic sources to illuminate the detailed structure of Kilauea volcano down to the decollement.  

Though large active-source surveys are widely conducted in the seismic industry, we have yet to apply these methods to active volcanic systems using a triaxial, controlled, seismic source.  Seismic interferometric imaging of sub-horizontal layering adjacent to salt domes has been shown to image salt dome dimensions precisely (Willis et al., 2006). These same methods become even more effective with a triaxial source, which generate separate P and S wavefields, and will be used at Kilauea volcano to image the magma system. A combined active and passive seismic experiment is planned for April and May 2022 that will produce more than 15 Tb of dense, high quality information on seismic wave fields propagating through the magma system of Kilauea volcano. With the combination of 3D active-source and ambient-noise surface-wave analyses and gravity constraints, the proposed seismic experiment provides a sound basis to substantially improve resolution of 3D velocity, density, and geologic structure from the surface to a depth of 10 km below Kilauea caldera, as well as provide a seismic data set that advances research in seismic wave propagation in the Earths crust.  

Description of the Research Opportunity:

The research opportunity follows on the seismic imaging objectives of the proposed active source project at Kilauea volcano in 2022. The Mendenhall Fellow will be stationed at the Hawaii Volcano Observatory in Hilo, HI. Interested applicants are strongly encouraged to contact the Research Advisor(s) early in the application process to discuss project ideas. 

Research areas include, but are not limited to:    

1. Active-source resolution of 3D P-wave structure from the near surface to 5 km depth beneath Kilauea volcano   
2. High-resolution 3D P-wave seismic reflection imaging from 4 km depth to 8 km depth beneath the summit of Kilauea over an area of at least 24 km2  
3. Resolve 3D S-wave velocity structure from the near-surface to 5 km depth, using active polarized shear-sourcing node data combined with HVO network, earthquake S wave arrival-time data from 2019-2022   
4. 3D shallow anisotropy structure in the top few kilometers of the crust, using polarized shear sourcing (from the vibroseis truck) to produce well-constrained Rayleigh- and Love-wave data from 3 Hz to 20 Hz and combined with ambient noise data below 1 Hz  
5. Resolution of 3D S-wave velocity and anisotropy structure in the 2-10 km depth range using full waveform body and (or) surface-wave tomography, earthquake S-wave first arrival-time data, the active source data, and the gravity survey for density structure constraints in a joint inversion. 

Given the computational demand of these research areas, a competitive applicant should have familiarity with high performance computing environments and workload managers / job schedules (Simple Linux Utility for Resource Management (SLURM), Torque, etc.). 

References :  

Neal, et al., 2019, https://doi:10.1126/science.aav7046 

Poland, et al., 2019, https://doi:10.1029/2019GL084901 

Willis, et al., 2006, https://doi.org/10.1190/1.2187711  

Proposed Duty Station: Hilo, HI 

Areas of PhD: Geophysics, seismology, or related fields (candidates holding a Ph.D. in other disciplines, but with extensive knowledge and skills relevant to the Research Opportunity may be considered). 

Qualifications: Applicants must meet the qualifications for: Research Geophysicist   

(This type of research is performed by those who have backgrounds for the occupations stated above.  However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.) 

Human Resources Office Contact: Beverly Ledbetter, 916-278-9396, bledbetter@usgs.gov 

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