Collaborative Research: Axial 3-D - Exploring the linkages between complex magma chamber structure, caldera dynamics, fluid pathways and hydrothermal venting

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

This study will obtain a high-resolution three-dimensional map of the internal structure of the underwater Axial Volcano, which is located about 450 km offshore of Washington State. These data will address the age-old question, "How do volcanoes really work?". Axial Volcano is an ideal location to obtain information on the underground magma chamber because a lot of other data have already been collected there. The surface features of Axial Volcano have been mapped in detail and the volcano is monitored in real-time through the Ocean Observatory Initiative Seafloor (OOI) Observatory. Obtaining an image of the magma chamber structure will complement existing data and the real-time data being provided by OOI, and allow a much better understanding of how Axial Volcano works and when it might erupt. This study will advance understanding of volcanoes both on land and underwater world wide. The project provides training for graduate students and early career scientists. Access to the data will be open. This project will complete a comprehensive 3-D multichannel seismic survey of Axial Volcano and associated rift axes aboard the R/V Marcus Langseth. In addition, eight 15-km-long source-receiver offset 2-D reflection profiles will be collected to look at deep-seated structure of magma delivery. A sophisticated set of seismic imaging tools focused on multichannel seismic data collected in underwater volcanic terrains has been developed. This algorithm approach has been used in a number of marine environments in 2-D, with the greatest success thus far at Axial Volcano, where the roof and floor of the underlying magma chamber have been clearly imaged, along with fractures/conduits in the upper crust connecting the magma chamber to nearby hydrothermal vent fields. Despite this success, Axial Volcano is inherently 3-D in nature, thus requiring a 3-D approach to map the complex connections between the magma plumbing system at depth with eruption dynamics at the seafloor. For example, this approach is needed to understand (1) how 3-D fracture sets are associated with magma inflation/withdrawal, rifting, and gravitational spreading/collapse in the upper crust; (2) the geometry and interconnection of complex magma bodies of varying amounts of melt/mush; (3) the relationship between internal structure and seafloor observables such as hydrothermal fields and lava flows. 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.