Asymmetric shallow mantle structure beneath the Hawaiian Swell—evidence from Rayleigh waves recorded by the PLUME network
Orcutt, John A.
Wolfe, Cecily J.
Collins, John A.
Solomon, Sean C.
Detrick, Robert S.
Hauri, Erik H.
MetadataShow full item record
KeywordMantle processes; Surface waves and free oscillations; Seismic tomography; Oceanic hotspots and intraplate volcanism; Pacific Ocean
We present models of the 3-D shear velocity structure of the lithosphere and asthenosphere beneath the Hawaiian hotspot and surrounding region. The models are derived from long-period Rayleigh-wave phase velocities that were obtained from the analysis of seismic recordings collected during two year-long deployments for the Hawaiian Plume-Lithosphere Undersea Mantle Experiment. For this experiment, broad-band seismic sensors were deployed at nearly 70 seafloor sites as well as 10 sites on the Hawaiian Islands. Our seismic images result from a two-step inversion of path-averaged dispersion curves using the two-station method. The images reveal an asymmetry in shear velocity structure with respect to the island chain, most notably in the lower lithosphere at depths of 60 km and greater, and in the asthenosphere. An elongated, 100-km-wide and 300-km-long low-velocity anomaly reaches to depths of at least 140 km. At depths of 60 km and shallower, the lowest velocities are found near the northern end of the island of Hawaii. No major velocity anomalies are found to the south or southeast of Hawaii, at any depth. The low-velocity anomaly in the asthenosphere is consistent with an excess temperature of 200–250 °C and partial melt at the level of a few percent by volume, if we assume that compositional variations as a result of melt extraction play a minor role. We also image small-scale low-velocity anomalies within the lithosphere that may be associated with the volcanic fields surrounding the Hawaiian Islands.
Author Posting. © The Author(s), 2011. This article is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 187 (2011): 1725–1742, doi:10.1111/j.1365-246X.2011.05238.x.
Suggested CitationArticle: Laske, Gabi, Markee, Amanda, Orcutt, John A., Wolfe, Cecily J., Collins, John A., Solomon, Sean C., Detrick, Robert S., Bercovici, David, Hauri, Erik H., "Asymmetric shallow mantle structure beneath the Hawaiian Swell—evidence from Rayleigh waves recorded by the PLUME network", Geophysical Journal International 187 (2011): 1725–1742, DOI:10.1111/j.1365-246X.2011.05238.x, https://hdl.handle.net/1912/4952
Showing items related by title, author, creator and subject.
Drilling the oceanic lower crust and mantle : a global strategy for exploring the deep oceanic crust and mantle in the 1990's Workshop on Drilling the Oceanic Lower Crust and Mantle (Woods Hole Oceanographic Institution, 1989-03)This workshop was convened to follow up on the Second Conference on Scientific Ocean Drilling (COSOD II) to devise a specific plan for deep crustal and mantle drilling over the next decade. Since COSOD II, however, there ...
Global mantle flow and the development of seismic anisotropy : differences between the oceanic and continental upper mantle Conrad, Clinton P.; Behn, Mark D.; Silver, Paul G. (American Geophysical Union, 2007-07-26)Viscous shear in the asthenosphere accommodates relative motion between Earth's surface plates and underlying mantle, generating lattice-preferred orientation (LPO) in olivine aggregates and a seismically anisotropic fabric. ...
Trace element geochemistry of oceanic peridotites and silicate melt inclusions : implications for mantle melting and ocean ridge magmagenesis Johnson, Kevin T. M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1990-06-15)The mantle melting process is fundamental to basalt genesis and crustal accretion at mid-ocean ridges. It is believed that melts ascend more rapidly than the surrounding mantle, implying a process similar to fractional ...