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dc.contributor.authorMarjanovic, Milena  Concept link
dc.contributor.authorCarton, Helene  Concept link
dc.contributor.authorCarbotte, Suzanne M.  Concept link
dc.contributor.authorNedimovic, Mladen R.  Concept link
dc.contributor.authorMutter, John C.  Concept link
dc.contributor.authorCanales, J. Pablo  Concept link
dc.date.accessioned2015-08-05T18:28:04Z
dc.date.available2015-08-05T18:28:04Z
dc.date.issued2015-06
dc.identifier.citationGeophysical Journal International 203 (2015): 1-21en_US
dc.identifier.urihttps://hdl.handle.net/1912/7451
dc.descriptionAuthor Posting. © The Author(s), 2015. This article is posted here by permission of The Royal Astronomical Society for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 203 (2015): 1-21, doi:10.1093/gji/ggv251.en_US
dc.description.abstractWe 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 multichannel seismic data acquired in 2008. The AVA crossplotting method, which has been developed for and, so far, applied for hydrocarbon prospection in sediments, is for the first time applied to a hardrock environment. We focus our analysis on 2-D data collected along the EPR axis from 9°29.8′N to 9°58.4′N, a region which encompasses the sites of two well-documented submarine volcanic eruptions (1991–1992 and 2005–2006). AVA crossplotting is performed for a ∼53 km length of the EPR spanning nine individual AML segments (ranging in length from ∼3.2 to 8.5 km) previously identified from the geometry of the AML and disruptions in continuity. Our detailed analyses conducted at 62.5 m interval show that within most of the analysed segments melt content varies at spatial scales much smaller (a few hundred of metres) than the length of the fine-scale AML segments, suggesting high heterogeneity in melt concentration. At the time of our survey, about 2 yr after the eruption, our results indicate that the three AML segments that directly underlie the 2005–2006 lava flow are on average mostly molten. However, detailed analysis at finer-scale intervals for these three segments reveals AML pockets (from >62.5 to 812.5 m long) with a low melt fraction. The longest such mushy section is centred beneath the main eruption site at ∼9°50.4′N, possibly reflecting a region of primary melt drainage during the 2005–2006 event. The complex geometry of fluid flow pathways within the crust above the AML and the different response times of fluid flow and venting to eruption and magma reservoir replenishment may contribute to the poor spatial correlation between incidence of hydrothermal vents and presence of highly molten AML. The presented results are an important step forward in our ability to resolve small-scale characteristics of the AML and recommend the AVA crossplotting as a tool for examining mid-ocean ridge magma-systems elsewhere.en_US
dc.description.sponsorshipThis research was supported by NSF awards OCE0327872 to J.C.M. and S.M.C., OCE-0327885 to J.P.C., and OCE0624401 to M.R.N.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherOxford University Pressen_US
dc.relation.urihttps://doi.org/10.1093/gji/ggv251
dc.subjectMid-ocean ridge processesen_US
dc.subjectSubmarine tectonics and volcanismen_US
dc.subjectCrustal structureen_US
dc.subjectPhysics of magma and magma bodiesen_US
dc.titleDistribution of melt along the East Pacific Rise from 9°30′ to 10°N from an amplitude variation with angle of incidence (AVA) techniqueen_US
dc.typeArticleen_US
dc.identifier.doi10.1093/gji/ggv251


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