Seismic anisotropy reveals focused mantle flow around the Calabrian slab (Southern Italy)

Publication Type  Journal Article
Year of Publication  2007
Authors  Baccheschi, P.; Margheriti, L.; Steckler, M. S.
Journal Title  Geophysical Research Letters
Volume  34
Issue  5
Pages  -
Journal Date  Mar 3
ISBN Number  0094-8276
Accession Number  ISI:000244707400005
Key Words  lattice preferred orientation; subduction; olivine; beneath; region; shear; zone; constraints; evolution; plate

SKS splitting at the Calabrian subduction zone, with delay times (delta t) up to 3s, reveals the presence of a strong anisotropic fabric. Fast directions (phi) are oriented NNE-SSW in the Calabrian Arc ( C. A.) and rotate NNW-SSE to the north following the arcuate shape of the subducting plate. We interpret the trench-parallel phi as local-scale mantle flow driven by the retrograde motion of the slab; the absence of trench perpendicular f below the Southern Apennines (S. A.) excludes the presence of a seismically detectable return flow at its NE edge. This may be due to the relative youth and limited width of the S. A. slab tear. A possible return flow is identified farther north at the boundary of the S. A. and Central Apennines. Different and weaker anisotropy is present below the Apulian Platform ( A. P.). This implies that the influence of the slab rollback in the sub-slab mantle is limited to less then 100 km from the slab.


143GFTimes Cited:5Cited References Count:33

URL  <Go to ISI>://000244707400005
DOI  Doi 10.1029/2006gl028899