Show simple item record

dc.contributor.authorCollins, John A.  Concept link
dc.contributor.authorSmith, Deborah K.  Concept link
dc.contributor.authorMcGuire, Jeffrey J.  Concept link
dc.date.accessioned2012-11-28T19:25:00Z
dc.date.available2014-10-22T08:57:23Z
dc.date.issued2012-10-09
dc.identifier.citationGeochemistry Geophysics Geosystems 13 (2012): Q0AG11en_US
dc.identifier.urihttps://hdl.handle.net/1912/5584
dc.descriptionAuthor Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 13 (2012): Q0AG11, doi:10.1029/2012GC004210.en_US
dc.description.abstractAt the oceanic core complex that forms the Atlantis Massif at 30°N on the Mid-Atlantic Ridge, slip along the detachment fault for the last 1.5–2 Ma has brought lower crust and mantle rocks to the seafloor. Hydroacoustic data collected between 1999 and 2003 suggest that seismicity occurred near the top of the Massif, mostly on the southeastern section, while detected seismicity along the adjacent ridge axis was sparse. In 2005, five short-period ocean bottom seismographs (OBS) were deployed on and around the Massif as a pilot experiment to help constrain the distribution of seismicity in this region. Analysis of six months of OBS data indicates that, in contrast to the results of the earlier hydroacoustic study, the vast majority of the seismicity is located within the axial valley. During the OBS deployment, and within the array, seismicity was primarily composed of a relatively constant background rate and two large aftershock sequences that included 5 teleseismic events with magnitudes between 4.0 and 4.5. The aftershock sequences were located on the western side of the axial valley adjacent to the Atlantis Massif and close to the ridge-transform intersection. They follow Omori's law, and constitute more than half of the detected earthquakes. The OBS data also indicate a low but persistent level of seismicity associated with active faulting within the Atlantis Massif in the same region as the hydroacoustically detected seismicity. Within the Massif, the data indicate a north-south striking normal fault, and a left-lateral, strike-slip fault near a prominent, transform-parallel, north-facing scarp. Both features could be explained by changes in the stress field at the inside corner associated with weak coupling on the Atlantis transform. Alternatively, the normal faulting within the Massif might indicate deformation of the detachment surface as it rolls over to near horizontal from an initial dip of about 60° beneath the axis, and the strike-slip events may indicate transform-parallel movement on adjacent detachment surfaces.en_US
dc.description.sponsorshipWe thank the Deep Ocean Exploration Institute at WHOI, Director of Research at WHOI, WHOI’s Department of Geology and Geophysics, and the National Science Foundation for funding the data collection.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.urihttps://doi.org/10.1029/2012GC004210
dc.subjectAtlantis Massifen_US
dc.subjectMid-Atlantic Ridgeen_US
dc.subjectT-phaseen_US
dc.subjectHydroacousticen_US
dc.subjectOceanic detachment faulten_US
dc.subjectSeismicityen_US
dc.titleSeismicity of the Atlantis Massif detachment fault, 30°N at the Mid-Atlantic Ridgeen_US
dc.typeArticleen_US
dc.description.embargo2013-04-09en_US
dc.identifier.doi10.1029/2012GC004210


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record