It is notoriously difficult to construct 3-D images of the magma plumbing systems that exist beneath volcanoes because uncovering the details of the magma system requires highly dense observations of a wide range of seismic events. At the same time, understanding these magma systems is vital because they play key roles in determining the nature and severity of hazards posed by volcanoes like Mt. St. Helens. This project is using modern exploration industry seismometers to provide dense observations of explosions and natural earthquakes in the rugged terrain around Mt. St. Helens. The data are being delivered to the IRIS Data Management Center, thereby providing the seismic community experience with a potential type of next-generation seismic array for structure and source studies. A team of undergraduate and graduate students, a postdoctoral scholar, and the PI from University of New Mexico are deploying the instruments in collaboration with an exploration industry service company (NodalSeismic of Long Beach, California). Students are gaining the opportunity to participate in a large multi-institution field campaign at Mt. St. Helens and experience with the operations of an innovative service company. Nearly all the UNM participants are also using the data in a new seismology class for senior undergraduates and graduate students at UNM, and undergraduate participants are also using the data for senior research projects.
This project is deploying about 1,000 Fairfield Nodal seismometers (nodes) to record continuously for two weeks in a dense array within about 15 km of Mt. St. Helens in order to obtain detailed 3-D seismic sampling of the magma plumbing system and surrounding crust. The deployment is leveraging 24 controlled sources detonated by the NSF-funded iMUSH project, and the nodes are providing 2 weeks of continuous recording of frequent local seismicity and ambient noise. Deployment of 1,000 nodes in the inner 15 km around MSH is greatly improving opportunities for 3-D imaging of the magma plumbing system with wave-field based methods and enabling high-resolution constraints on locations and mechanisms of seismicity that could provide insight into melt/fluid transport processes beneath arc volcanoes.
