NSF Award
2317687
Mauna Loa volcano on the Island of Hawaii is the world’s largest volcano. Compared with its southeastern neighbor Kilauea, Mauna Loa has not been extensively investigated due to its steep slopes, high elevation, and relative lack of activity. On November 27, 2022, an eruption began in the summit crater of Mauna Loa and extended to the Northeast Rift Zone, a crack on the northeast flank of the volcano. Past eruptions at Mauna Loa have occurred on both the Northeast and Southwest Rift Zones, and the population has grown around the latter. It is therefore imperative for researchers to understand the magmatic “plumbing system” before the next eruption takes place. In this project, the PI team will deploy 54 seismometers on and around the volcano for three months to obtain records of shaking from local and distant earthquakes. They will analyze data from these and other seismometers to map local earthquakes, and make a detailed 3D image of the subsurface (similar to a CT scan at a hospital) using data from all of the recorded quakes. The new images and the pattern of local earthquakes will show magma chambers and possible routes for magma to ascend to the surface, and comparisons with results from future studies will show how magma is migrating below the volcano over time. The new findings will help the PI team, their collaborators at the USGS Hawaiian Volcano Observatory, and other scientists better understand seismic and volcanic hazards associated with Mauna Loa. This project will also provide training in volcano seismology for a postdoctoral scholar and two undergraduate students.<br/><br/>In this three-year project, the team will apply the state-of-the-art seismic techniques to the digital data recorded by the permanent seismic stations at the USGS Hawaiian Volcano Observatory and a nodal array during a three-month experiment to assess the high-resolution velocity structure and seismic characteristics of Mauna Loa volcano. The data will be used to generate an automatic earthquake catalog, to image the magmatic system, to estimate in-situ Poisson’s ratio in the near earthquake source regions, and to examine temporal variations in seismic velocity. The newly developed velocity models are invaluable in resolving conduits and magma chambers and improving absolute earthquake locations. In situ Poisson’s ratios with high-resolution are of great help to tracking magma movement and estimating the fraction of partial melt. The following questions will be addressed in this project: 1. What will the simultaneous inversions of the high-resolution Vp, Vs, and Vp/Vs models reveal about the magmatic system and possible magma bodies? (What role did these magma bodies play in the 2022 eruption and why did the 2022 eruption produce such a small eruptive volume after over 38 years of repose?) 2. What will the absolute earthquake location constraints from 3D velocity models tell us about the fault zones in Mauna Loa? 3. What will the high-resolution in situ Vp/Vs ratios estimated from waveform cross-correlation data reveal about the spatial and temporal characteristics in the near-source region? 4. How do the long-lasting seismic velocity variations in Mauna Loa compare to those in other parts of Hawaii and at other volcanoes?<br/><br/>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.
