Crustal structure and subduction erosion in the central Costa Rica subduction zone [Elektronische Ressource] / vorgelegt von Junjiang Zhu

Crustal structure and subduction erosionin the central Costa Rica subduction zoneDissertationzur Erlangung des Doktorgradesder Mathematischen-Naturwissenschaftlichen Fakultätder Christian-Albrechts-Universität zu Kielvorgelegt vonJunjiang ZhuKiel, 2100Referentin: Prof. Dr. Heidrun KoppKoreferent:rof. Dr. Ernst FluehTag der mündlichen Prüfung: 10. Februar 2010Zum Druck genehmigt: 20. Juli 2010 Der Dekan gez. II III IVABSTRACTOn the Pacific margin off central Costa Rica, an anomalous lens-shaped zone islocated between the overriding plate and the subducting oceanic lithosphere approximately 25 km landward of the deformation front. This feature was previously recognized in reflection seismic data when it was termed ‘megalens’. Its origin andseismic velocity structure, however, could not unambiguously be derived from earlier studies. Therefore during RV SONNE cruise SO163 in 2002, seismic wide-angle da tawere acquired using closely spaced ocean bottom hydrophones and seismometers along two parallel strike lines and two parallel dip lines above the ‘megalens’, intersecting on the middle slope.