Thermal structure of oceanic transform faults
MetadataShow full item record
KeywordOceanic transform faults; Mid-ocean ridges; Fault rheology; Intratransform spreading centers
We use three-dimensional finite element simulations to investigate the temperature structure beneath oceanic transform faults. We show that using a rheology that incorporates brittle weakening of the lithosphere generates a region of enhanced mantle upwelling and elevated temperatures along the transform; the warmest temperatures and thinnest lithosphere are predicted to be near the center of the transform. Previous studies predicted that the mantle beneath oceanic transform faults is anomalously cold relative to adjacent intraplate regions, with the thickest lithosphere located at the center of the transform. These earlier studies used simplified rheologic laws to simulate the behavior of the lithosphere and underlying asthenosphere. We show that the warmer thermal structure predicted by our calculations is directly attributed to the inclusion of a more realistic brittle rheology. This temperature structure is consistent with a wide range of observations from ridge-transform environments, including the depth of seismicity, geochemical anomalies along adjacent ridge segments, and the tendency for long transforms to break into small intratransform spreading centers during changes in plate motion.
Author Posting. © Geological Society of America, 2007. This article is posted here by permission of Geological Society of America for personal use, not for redistribution. The definitive version was published in Geology 35 (2007): 307-310, doi:10.1130/G23112A.1.
Showing items related by title, author, creator and subject.
Thermal-mechanical behavior of oceanic transform faults : implications for the spatial distribution of seismicity Roland, Emily C.; Behn, Mark D.; Hirth, Greg (American Geophysical Union, 2010-07-01)To investigate the spatial distribution of earthquakes along oceanic transform faults, we utilize a 3-D finite element model to calculate the mantle flow field and temperature structure associated with a ridge-transform-ridge ...
Boettcher, Margaret S.; Jordan, T. H. (American Geophysical Union, 2004-12-09)A mid-ocean ridge transform fault (RTF) of length L, slip rate V, and moment release rate dot above M can be characterized by a seismic coupling coefficient χ = A E/A T, where A E ∼ dot above M/V is an effective seismic ...
Trehu, Anne M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1982-02)In this thesis, seismic waves generated by sources ranging from 2.7 kg shots of TNT to magnitude 5 earthquakes are studied in order to determine the seismic activity and crustal structure of the Orozco transform fault. ...