DOUG TOOMEY Professor of Geophysics
The Santorini Seismic Experiment is using seismic methods to examine the entire crustal magma plumbing system beneath Santorini volcano. Santorini is unique for this study because it recently experienced significant unrest; inflation of the ground and intense earthquake swarms during 2011-2013. It is also geologically well-studied. It is an ideal location because is a semi-submerged volcanic system which makes it possible to collect dense 3D marine-land seismic data.
The Cascadia Initiative (CI) is an onshore/offshore seismic and geodetic experiment that takes advantage of an Amphibious Array to study questions ranging from megathrust earthquakes to volcanic arc structure to the formation, deformation and hydration of the Juan De Fuca and Gorda plates.
Toomey, D.R., R.M. Allen, A.H. Barclay, S.W. Bell, P.D. Bromirski, R.L. Carlson, X. Chen, J.A. Collins, R.P. Dziak, B. Evers, D.W. Forsyth, P. Gerstoft, E.E.E. Hooft, D. Livelybrooks, J.A. Lodewyk, D.S. Luther, J.J. McGuire, S.Y. Schwartz, M. Tolstoy, A.M. Tréhu, M. Weirathmueller, and W.S.D. Wilcock. 2014. The Cascadia Initiative: A sea change in seismological studies of subduction zones. Oceanography 27(2):138–150
The Endeavour seismic tomography experiment (ETOMO) experiment tests competing models for what controls the segmentation and intensity of ridge crest processes. Existing models are at odds on the scale of mantle and crustal magmatic segmentation, the distribution of hydrothermal venting with respect to a volcanic segment and the properties of the thermal boundary layer that transports energy between the magmatic and hydrothermal systems. The recent discovery of an axial magma chamber (AMC) reflector beneath the Endeavour segment of the Juan de Fuca ridge, as well as systematic along axis changes in seafloor depth, ridge crest morphology and hydrothermal venting provide an ideal target for testing models of the origin of segmentation at mid-ocean ridges.
HOOFT, E. E. E., H. PATEL, W. WILCOCK, K. BECKER, D. BUTTERFIELD, E. DAVIS, R. DZIAK, K. INDERBITZEN, M. LILLEY, P. MCGILL, D. TOOMEY AND D. STAKES, A SEISMIC SWARM AND REGIONAL HYDROTHERMAL AND HYDROLOGIC PERTURBATIONS: THE NORTHERN ENDEAVOUR SEGMENT, FEBRUARY 2005, GEOCHEM. GEOPHYS. GEOSYST. , 11 , Q12015, DOI:10.1029/2010GC003264, 2010.
Byrnes, J., E. E. E. Hooft, D. R. Toomey, D. R. Villagómez, D. J. Geist, and S. C. Solomon, An upper-mantle seismic discontinuity beneath the Galápagos Archipelago and its implications for studies of the lithosphere-asthenosphere boundary, Geochem. Geophys. Geosyst., in press.
Villagomez, D. R., D. R. Toomey, D. J. Geist, E. E. E. Hooft and S. C. Solomon, Mantle flow and multistage melting beneath the GalApagos hotspot revealed by seismic imaging, Nature Geoscience, doi:10.1038/NGEO2062, 2014.
Villagomez, D. R., D. R. Toomey, E. E. E. Hooft and S. C. Solomon, Crustal structure beneath the Galápagos Archipelago from ambient noise tomography and its implications for plume-lithosphere interactions, J. Geophys. Res., 116, B04310, doi:10.1029/2010JB007764, 2011.
EAST PACIFIC RISE:
Toomey, D. R. PLATE TECTONICS: Piecing together rifts. Nature Publishing Group 5, 235–236 (2012).
Durant, D. T. and D. R. Toomey, Evidence and implications of a crustal magmatism on the flanks of the East Pacific Rise, Earth and Planet. Sci. Lett., 287, 130-136, 2009
Toomey, D.R. and E. E. E. Hooft, Mantle upwelling, magmatic differentiation, and the meaning of axial depth at fast-spreading ridges, Geology, 36, doi:10.1130/G24834A.1, 679-682, 2008.
Toomey, D. R., D. Jousselin, R. A. Dunn, W. S. D. Wilcock and R. S. Detrick, Skew of mantle upwelling beneath the East Pacific Rise Governs Segmentation, Nature, 444, doi:10.1038/nature05679, 409-414, 2007.