MARGINS: Collaborative Research: Illuminating the Architecture of the Greater Mount St. Helens Magmatic Systems from Slab to Surface

Lead PI: Geoffrey Abers

Unit Affiliation: Seismology, Geology and Tectonophysics, Lamont-Doherty Earth Observatory (LDEO)

June 2012 - May 2014
North America ; Mount St. Helens
Project Type: Research

DESCRIPTION: The team used a variety of geophysical imaging techniques (magnetotelluric coupled with high-resolution passive and active source seismic imaging) integrated with geochemical-petrological data to image the crust and upper mantle in the greater Mount St. Helens area.

To better understand volcanic activity, it is fundamental to get an accurate representation of magma generation zones and storage regions in the Earth's crust and upper mantle. Illuminating the architecture of the plumbing system beneath volcanoes will allow scientists to determine (1) at which depths and conditions magmas are generated, and (2) the shapes and sizes of pathways and reservoirs along which magma travels towards the surface. Such knowledge will allow scientists to make more informed predictions on the durations of volcanic crises and on the total volume of erupted material during eruptive episodes.

This project focuses on the Mount St. Helens volcanic edifice, (WA, USA), whose explosive eruption in 1980 attracted world's attention, and was the first volcano to be thoroughly monitored with modern instruments. Mount St. Helens provides an ideal setting to apply state-of-the-art geophysical and geochemical techniques to image its subterranean roots: It is active, easily accessible, and has a well recorded past history. The project will use several different methods (active and passive source seismic tomography and scattered wave imaging, magnetotelluric imaging, petrology and geochemistry), involving a large collaborative team, to image the volcano's plumbing system with unprecedented resolution from the subducting plate to the surface. The results will be informative for many other volcanoes around the world, particularly those located along the infamous Pacific Ring of Fire.