Constraints on melt content of off-axis magma lenses at the East Pacific Rise from analysis of 3-D seismic amplitude variation with angle of incidence
Nedimovic, Mladen R.
Carbotte, Suzanne M.
Canales, J. Pablo
MetadataShow full item record
KeywordEast Pacific Rise; Oceanic crust; Multichannel seismic data; 3-D reflection imaging; Off-axis magma lens; Amplitude variation with angle of incidence (AVA)
We use 3-D multichannel seismic data to form partial angle P wave stacks and apply amplitude variation with angle (AVA) crossplotting to assess melt content and melt distribution within two large midcrustal off-axis magma lenses (OAMLs) found along the East Pacific Rise from 9°37.5′N to 9°57′N. The signal envelope of the partial angle stacks suggests that both OAMLs are partially molten with higher average melt content and more uniform melt distribution in the southern OAML than in the northern OAML. For AVA crossplotting, the OAMLs are subdivided into seven ~1 km2 analysis windows. The AVA crossplotting results indicate that the OAMLs contain a smaller amount of melt than the axial magma lens (AML). For both OAMLs, a higher melt fraction is detected within analysis windows located close to the ridge axis than within the most distant windows. The highest average melt concentration is interpreted for the central sections of the OAMLs. The overall low OAML melt content could be indicative of melt lost due to recent off-axis eruptions, drainage to the AML, or limited mantle melt supply. Based on the results of this and earlier bathymetric, morphological, geochemical, and geophysical investigations, we propose that the melt-poor OAML state is largely the result of limited melt supply from the underlying mantle source reservoir with smaller contribution attributed to melt leakage to the AML. We hypothesize that the investigated OAMLs have a longer period of melt replenishment, lower eruption recurrence rates, and lower eruption volumes than the AML, though some could be single intrusion events.
Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 122 (2017): 4123–4142, doi:10.1002/2016JB013785.
Suggested CitationArticle: Aghaei, Omid, Nedimovic, Mladen R., Marjanovic, Milena, Carbotte, Suzanne M., Canales, J. Pablo, Carton, Helene, Nikić, Nikola, "Constraints on melt content of off-axis magma lenses at the East Pacific Rise from analysis of 3-D seismic amplitude variation with angle of incidence", Journal of Geophysical Research: Solid Earth 122 (2017): 4123–4142, DOI:10.1002/2016JB013785, https://hdl.handle.net/1912/9161
Showing items related by title, author, creator and subject.
Distribution of melt along the East Pacific Rise from 9°30′ to 10°N from an amplitude variation with angle of incidence (AVA) technique Marjanovic, Milena; Carton, Helene; Carbotte, Suzanne M.; Nedimovic, Mladen R.; Mutter, John C.; Canales, J. Pablo (Oxford University Press, 2015-06)We examine along-axis variations in melt content of the axial magma lens (AML) beneath the fast-spreading East Pacific Rise (EPR) using an amplitude variation with angle of incidence (AVA) crossplotting method applied to ...
Variations in axial magma lens properties along the East Pacific Rise (9°30′N–10°00′N) from swath 3-D seismic imaging and 1-D waveform inversion Xu, Min; Canales, J. Pablo; Carbotte, Suzanne M.; Carton, Helene; Nedimovic, Mladen R.; Mutter, John C. (John Wiley & Sons, 2014-04-29)We use three-dimensional multistreamer seismic reflection data to investigate variations in axial magma lens (AML) physical properties along the East Pacific Rise between 9°30′N and 10°00′N. Using partial-offset stacks of ...
Greaves, Robert J. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1998-06)The goal of this thesis is to develop a methodology to interpret sound scattered from the seafloor in terms of seafloor structure and subseafloor geological properties. Specifically, this work has been directed towards ...