| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | August 12, 2021 |
| Latest Amendment Date: | August 12, 2021 |
| Award Number: | 2113315 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Wendy Panero
wpanero@nsf.gov (703)292-5058 EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | August 15, 2021 |
| End Date: | July 31, 2024 (Estimated) |
| Total Intended Award Amount: | $106,431.00 |
| Total Awarded Amount to Date: | $106,431.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
1 UNIVERSITY OF NEW MEXICO ALBUQUERQUE NM US 87131-0001 (505)277-4186 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
NM US 87131-0001 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): |
Geophysics, Special Initiatives |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
The Valles caldera is one of three supervolcanoes in North America and has a long history of volcanism with documented magma flows as recent as ~70,000 years. Seismic imaging allows visualization of volcanic subterranean structures by using seismic waves in a similar way ultrasound sonography in medical imaging. Seismic imaging of the Valles Caldera was lacking until recently, which in turn has hindered estimate of melt volumes, melt extent, and understanding of the plumbing system. A joint University of Texas at El Paso (UTEP)/University of New Mexico (UNM) deployment in 2019 resulted in a 97-seismometer line crossing the entire caldera for 1 month. A primary objective of this initiative is to resolve the spatial extent and concentration of melt under the caldera, with other standing questions including the depth of any magma body underlying the dome, the thickness of intra-caldera fill and fractured basement blocks, and the nature of the crust/mantle boundary. Using cutting edge techniques, researchers probe and unveil the subterranean magmatic system of the volcano and foster a collaboration between UTEP and UNM, two minority serving institutions. The outcomes of this project improve earthquake and volcanic hazard assessment in the region, and support the training of graduate and undergraduate students from underrepresented minorities in science.
The Valles caldera, a Quaternary-active supervolcanoes, is the textbook example of a resurgent caldera. It has largely escaped seismic scrutiny in the past two decades. Here the researchers probe the magmatic system beneath Valles caldera. They quantify the spatial extent of melt structures, the depth and emplacement of scattering boundaries, and assess the assumed aseismic nature of the caldera system. Ambient noise seismic interferometry is leveraged to estimate dispersion curves for long period Rayleigh and Love waves; these will be jointly inverted in a transdimensional Bayesian scheme with receiver functions, H/V ratios, and noise autocorrelations. The goal is to accurately estimate velocity structures under the Valles caldera. Targets include bounding the spatial extent and concentration of melt through shear-wave velocity and Vp/Vs estimates, depth to magmatic structures and caldera fill under the resurgent dome through scattered wave analysis, and detection and location of any local seismicity that may reveal magma and fluid movements. This project complements sparser long-term seismic monitoring efforts by Los Alamos National laboratory. It serves as an educational primer and complement to frequent geophysics field camps using the caldera as a natural laboratory. Its outcomes improve the assessment of the volcano life-cycle stage and allow better comparison with other Quaternary supervolcanoes.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The project researched potential magma system structure and earthquake activity beneath Valles Caldera and the surrounding Jemez uplift of northern New Mexico. The area presents vivid geologic evidence of volcanic activity and fault slip, but sparse measurements of modern deformation and seismicity indicate only subtle activity over the past few decades. This project sought to better evaluate whether there is still magma storage in the upper crust beneath Valles Caldera because it important for understanding links between activity measured over short time scales with modern instruments and the longer geologic record. Bridging these time scales of information is valuable for assessing hazards to critical infrastructure, particularly in northern New Mexico.
Seismic surface wave imaging using temporary seismic array data and correlations of background noise signals constrained three-dimensional shear velocity structure in the middle to upper crust (depths less than about 15-20 km below the surface). Beneath the central portion of the caldera, within its inner ring fracture, shear velocities at about 3-8 km depth were found to be much lower than in the surrounding area and consistent with the ongoing presence of up to 16-20% magma occupying the pore space between solid mineral crystals. Using two types of surface waves, Rayleigh and Love waves, further indicated that the magma storage volume is organized into horizontally-elongated sub-structures with contrasting properties. This result suggests the presence of geological structures called sills in which melt is concentrated in layers bounded by relatively melt-free rock.
Temporary seismic array data were also used to detect and locate small earthquakes with machine learning based methods. Only a few small earthquakes near the detection limit for the temporary 95-seismograph array were found directly beneath the caldera, but more than 200 small earthquakes were identified beneath the surrounding Jemez uplift. The most concentrated activity was beneath the Gallina and Nacimiento faults west of Valles Caldera. Although nearly all these earthquakes are too small to be felt by humans, they provide important evidence that the faults on the western edge of the Jemez uplift are still active.
Multiple graduate students at the University of New Mexico received training in modern passive source seismic methods for structural imaging and microseismicity detection, which are important to a range of careers in private industry and governmental hazard mitigation agencies. Field and computational aspects of the project were leveraged to design and implement a geophysical module in the Jemez uplift for the University of New Mexico’s undergraduate capstone course in field methods in 2023 and 2024. About twenty students received training in collection of field geophysics data with multiple methods, computational analysis and data synthesis after returning from the field, and communication of their results in written and oral formats.
Last Modified: 12/02/2024
Modified by: Brandon Schmandt
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