iMUSH: Imaging Magma Under St. Helens

iMUSH was a four year collaborative research project involving several institutions and supported by the GeoPRISMS and EarthScope Programs of the US National Science Foundation to illuminate the architecture of the greater Mount St. Helens magmatic system from slab to surface.


May 18th 2020 marks the 40th anniversary of the big 1980 Mount Saint Helens’ eruption. See below a list of virtual events that are organized to commemorate the eruption and share what we have learnt since then.

 icon-chevron-right Mount St. Helens isn’t where it should be. Scientists may finally know why | National Geographic, May 18, 2020

 icon-chevron-right Mount St. Helens and the Cascade Range Volcanoes – The 40th Anniversary

May 18th 6:30 PM PDT, followed by live Q&A at 8:00pm

Live on Youtube at:
and Facebook at:

Four northwest scientists will present a review of Cascadia Region tectonics, volcanoes, volcanic hazards, and a summary of how the science and monitoring has evolved over the last 40 years. It will also include first person accounts of the buildup to the May 18, 1980 eruption as experienced by University of Washington seismologist Steve Malone.

Hosted by the Pacific Northwest Seismic Network, moderated by PNSN Director Harold Tobin, with presenters Dr Jackie Caplan-Auerbach, Dr Joe Dufek, Dr Seth Moran and Dr Steve Malone.

icon-chevron-right University of Washington Experts on Mount St Helens

About the iMUSH project

iMUSH was a four year collaborative research project involving several institutions and supported by the GeoPRISMS and EarthScope Programs of the US National Science Foundation to illuminate the architecture of the greater Mount St. Helens magmatic system from slab to surface.

To determine the architecture of magmatic systems in general, including the extent and characteristics of highly crystalline magma bodies, and to resolve major tectonic controls on volcanism along the Cascade arc, a variety of geophysical imaging techniques such as magnetotelluric, high-resolution active source seismic imaging and passive seismic monitoring and imaging, integrated with geochemical-petrological data, were used to image and interpret the crust and upper mantle in the greater Mount St. Helens area.

Left: Map of the active source deployment. In the summer of 2014, 23 shots were recorded by about 2500 Texan seismometers installed in two deployments, in addition to 950 Nodal seismometers. The black line shows the location of cross-sections in Figure 2. Right: Locations of permanent and temporary broadband seismometers used in the passive source experiment, magnetotelluric sites, and petrologic samples.

Participant list

Eight Principal Investigators (PIs) from six different institutions were collaborating on the iMUSH project. In addition to these NSF funded investigators, five Investigators from the three US Geological Survey research groups were closely involved with several parts of the project.

  • Geoffrey A Abers (Cornell University)
  • Olivier Bachmann (ETH-Zurich)
  • Paul Bedrosian (USGS)
  • Dawnika L Blatter (USGS)
  • Esteban Bowles-Martinez (Oregon State University)
  • Michael A Clynne (USGS)
  • Kenneth C Creager (University of Washington)
  • Kayla Crosbie (Cornell University)
  • Roger P Denlinger (USGS)
  • Margaret E Glasgow (University of New Mexico)
  • Jiangang Han (University of Washington)
  • Steven M Hansen (University of New Mexico)
  • Graham J Hill University of Canterbury
  • Eric Kiser (University of Arizona)
  • Alan Levander (Rice University)
  • Michael Mann (Cornell University)
  • Xiaofeng Meng (University of Washington)
  • Seth C Moran (USGS)
  • Jared Peacock (USGS)
  • Brandon Schmandt (University of New Mexico)
  • Adam Schultz (Oregon State University)
  • Thomas W Sisson (USGS)
  • Roque A Soto Castaneda (Cornell University)
  • Weston A Thelen (USGS)
  • Carl W Ulberg (University of Washington)
  • John E Vidale (University of Washington)
  • Maren Wanke (ETH-Zurich)

iMUSH is funded by NSF-GeoPRISMS, NSF-Earthscope with substantial in-kind support from the USGS.

Visit the iMUSH website for more information about the project.

PublicationsNewsletter and press reports

Ulberg, C.W., K.C. Creager, S.C. Moran, G.A. Abers, A. Levander, E. Kiser, B. Schmandt, S. Hansen, R. Crosson, 2020. Local source Vp and Vs tomography in the Mount St Helens region with the iMUSH broadband array. Geochemistry, Geophysics, Geosystems, 21, e2019GC00888. doi: 10.1029/2019GC008888

Crosbie, K.J., G.A. Abers, M.E. Mann, H.A. Janiszewski, K.C. Creager, C. Ulberg, S. Moran, 2019. Shear velocity structure from ambient noise and teleseismic surface wave tomography in the Cascades around Mount St. Helens. Journal of Geophysical Research, v. in press.

Eakin, C.M., E.A. Wirth, A. Wallace, C.W. Ulberg, K.C. Creager, G.A. Abers, 2019. SKS splitting beneath Mount St. Helens: Constraints on subslab mantle entrainment. Geochemistry, Geophysics, Geosystems, 20, 4202–4217.

Kiser, E., A. Levander, C. Zelt, B. Schmandt, S. Hansen, 2019. Upper crustal structure and magmatism in southwest Washington: Vp, Vs, and Vp/Vs results from the iMUSH active-source seismic experiment. Journal of Geophysical Research: Solid Earth, 124(7), 7067-7080.

Mann, M.E., G.A. Abers, K.J. Crosbie, K.C. Creager, C. Ulberg, S. Moran, S. Rondenay, 2019. Imaging subduction beneath Mount St. Helens: Implications for slab dehydration and magma transport. Geophysical Research Letters, 46, 3163–3171,

Wanke, M., M.A. Clynne, A. von Quadt, T.W. Vennemann, O. Bachmann, 2019. Geochemical and petrological diversity of mafic magmas from Mount St. Helens. Contributions to Mineralogy and Petrology, 174, 10.

Wanke, M., O. Karakas, O. Bachmann, 2019. The genesis of arc dacites: The case of Mount St. Helens, WA. Contributions to Mineralogy and Petrology, 174, 7.

Bedrosian, P.A., J.R. Peacock, E. Bowles-Martinez, A. Schultz, G.J. Hill, 2018. Crustal inheritance and a top-down control on arc magmatism at Mount St. Helens: Nature Geoscience, 11, 865–870.

Glasgow, M.E., B. Schmandt, S.M. Hansen, 2018. Upper crustal low-frequency seismicity at Mount St. Helens detected with a dense geophone array. Journal of Volcanology and Geothermal Research, 358, 329–341.

Han, J., J.E. Vidale, H. Houston, D.A. Schmidt, K.C. Creager, 2018. Deep long‐period earthquakes beneath Mount St. Helens: Their relationship to tidal stress, episodic tremor and slip, and regular earthquakes. Geophysical Research Letters, 45, 2241–2247.

Kiser, E., A. Levander, C. Zelt, B. Schmandt, S. Hansen, 2018. Focusing of melt near the top of the Mount St. Helens (USA) magma reservoir and its relationship to major volcanic eruptions. Geology, 46, 775–778.

Blatter, D.L., T.W. Sisson, W.B. Hankins, 2017. Voluminous arc dacites as amphibole reaction-boundary liquids. Contributions to Mineralogy and Petrology, 172, doi:10.1007/s00410-017-1340-6

Olson, S., 2017. The Next Big Bang. Scientific American, 317(5), 34-41 10.1038/scientificamerican1117-34

Wang, Y., F. Lin, B. Schmandt, J. Farrell, 2017. Ambient noise tomography across Mount St. Helens using a dense seismic array. Journal of Geophysical Research: Solid Earth, 122, 4492–4508.

Hansen, S.M., B. Schmandt, A. Levander, E. Kiser, J.E. Vidale, G.A. Abers, K.C. Creager, 2016. Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens. Nature Communications, 7, 13242, doi:10.1038/ncomms13242.

Kiser, E., I. Palomeras, A. Levander, C. Zelt, S. Harder, B. Schmandt, S. Hansen, K. Creager, C. Ulberg, 2016. Magma reservoirs from the upper crust to the Moho inferred from high-resolution Vp and Vs models beneath Mount St. Helens, Washington State, USA. Geology, 44, 411–414.

Hansen, S.M., B. Schmandt, 2015. Automated detection and location of microseismicity at Mount St. Helens with a large-N geophone array. Geophysical Research Letters, 42, 7390–7397.

icon-chevron-right Science Report – Imaging Magma Under Mount St. Helens with Geophysical and Petrologic Methods | Carl Ulberg and the iMUSH Team, GeoPRISMS Newsletter #39 – Fall 2017

 icon-chevron-right Report from the Field – iMUSH: Imaging Magma Under St. Helens | Carl Ulberg and the iMUSH Team, GeoPRISMS Newsletter #34 – Spring 2015

 icon-chevron-right Press reports are listed on the iMUSH project website

icon-chevron-right Brandon Schmandt video recordings, part of the GeoPRISMS Lecture Series. University of Oregon, Eugene, OR, May 2018