Seismic investigation of the transition from continental to oceanic subduction along the western Hellenic Subduction Zone
The western Hellenic subduction zone (WHSZ) exhibits well-documented along-strike variations in lithosphere density (i.e., oceanic versus continental), subduction rates, and overriding plate extension. Differences in slab density are believed to drive deformation rates along the WHSZ; however, this...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | en_US |
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American Geophysical Union
2014
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| Online Access: | http://hdl.handle.net/1721.1/85853 https://orcid.org/0000-0002-6485-0026 |
| _version_ | 1811072111400189952 |
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| author | Pearce, Frederick Douglas Rondenay, S. Sachpazi, M. Charalampakis, M. Royden, Leigh H |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Pearce, Frederick Douglas Rondenay, S. Sachpazi, M. Charalampakis, M. Royden, Leigh H |
| author_sort | Pearce, Frederick Douglas |
| collection | MIT |
| description | The western Hellenic subduction zone (WHSZ) exhibits well-documented along-strike variations in lithosphere density (i.e., oceanic versus continental), subduction rates, and overriding plate extension. Differences in slab density are believed to drive deformation rates along the WHSZ; however, this hypothesis has been difficult to test given the limited seismic constraints on the structure of the WHSZ, particularly beneath northern Greece. Here, we present high-resolution seismic images across northern and southern Greece to constrain the slab composition and mantle wedge geometry along the WHSZ. Data from two temporary arrays deployed across Greece in a northern line (NL) and southern line (SL) are processed using a 2D teleseismic migration algorithm based on the Generalized Radon Transform. Images of P- and S-wave velocity perturbations reveal N60E dipping low-velocity layers beneath both NL and SL. The ∼8 km thick layer beneath SL is interpreted as subducted oceanic crust while the ∼20 km thick layer beneath NL is interpreted as subducted continental crust. The thickness of subducted continental crust inferred within the upper mantle suggests that ∼10 km of continental crust has accreted to the overriding plate. The relative position of the two subducted crusts implies ∼70–85 km of additional slab retreat in the south relative to the north. Overall, our seismic images are consistent with the hypothesis that faster sinking of the denser, oceanic portion of the slab relative to the continental portion can explain the different rates of slab retreat and deformation in the overriding plate along the WHSZ. |
| first_indexed | 2024-09-23T09:01:04Z |
| format | Article |
| id | mit-1721.1/85853 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T09:01:04Z |
| publishDate | 2014 |
| publisher | American Geophysical Union |
| record_format | dspace |
| spelling | mit-1721.1/858532024-05-15T05:11:26Z Seismic investigation of the transition from continental to oceanic subduction along the western Hellenic Subduction Zone Pearce, Frederick Douglas Rondenay, S. Sachpazi, M. Charalampakis, M. Royden, Leigh H Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Pearce, Frederick Douglas Royden, Leigh H. The western Hellenic subduction zone (WHSZ) exhibits well-documented along-strike variations in lithosphere density (i.e., oceanic versus continental), subduction rates, and overriding plate extension. Differences in slab density are believed to drive deformation rates along the WHSZ; however, this hypothesis has been difficult to test given the limited seismic constraints on the structure of the WHSZ, particularly beneath northern Greece. Here, we present high-resolution seismic images across northern and southern Greece to constrain the slab composition and mantle wedge geometry along the WHSZ. Data from two temporary arrays deployed across Greece in a northern line (NL) and southern line (SL) are processed using a 2D teleseismic migration algorithm based on the Generalized Radon Transform. Images of P- and S-wave velocity perturbations reveal N60E dipping low-velocity layers beneath both NL and SL. The ∼8 km thick layer beneath SL is interpreted as subducted oceanic crust while the ∼20 km thick layer beneath NL is interpreted as subducted continental crust. The thickness of subducted continental crust inferred within the upper mantle suggests that ∼10 km of continental crust has accreted to the overriding plate. The relative position of the two subducted crusts implies ∼70–85 km of additional slab retreat in the south relative to the north. Overall, our seismic images are consistent with the hypothesis that faster sinking of the denser, oceanic portion of the slab relative to the continental portion can explain the different rates of slab retreat and deformation in the overriding plate along the WHSZ. National Science Foundation (U.S.) (project MEDUSA, funded by the NSF Continental Dynamics Program, grant EAR-0409373) 2014-03-20T18:46:14Z 2014-03-20T18:46:14Z 2012-07 2012-06 Article http://purl.org/eprint/type/JournalArticle 0148-0227 http://hdl.handle.net/1721.1/85853 Pearce, F. D., S. Rondenay, M. Sachpazi, M. Charalampakis, and L. H. Royden. “Seismic Investigation of the Transition from Continental to Oceanic Subduction Along the Western Hellenic Subduction Zone.” Journal of Geophysical Research 117, no. B7 (2012). https://orcid.org/0000-0002-6485-0026 en_US http://dx.doi.org/10.1029/2011jb009023 Journal of Geophysical Research Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Geophysical Union Other repository |
| spellingShingle | Pearce, Frederick Douglas Rondenay, S. Sachpazi, M. Charalampakis, M. Royden, Leigh H Seismic investigation of the transition from continental to oceanic subduction along the western Hellenic Subduction Zone |
| title | Seismic investigation of the transition from continental to oceanic subduction along the western Hellenic Subduction Zone |
| title_full | Seismic investigation of the transition from continental to oceanic subduction along the western Hellenic Subduction Zone |
| title_fullStr | Seismic investigation of the transition from continental to oceanic subduction along the western Hellenic Subduction Zone |
| title_full_unstemmed | Seismic investigation of the transition from continental to oceanic subduction along the western Hellenic Subduction Zone |
| title_short | Seismic investigation of the transition from continental to oceanic subduction along the western Hellenic Subduction Zone |
| title_sort | seismic investigation of the transition from continental to oceanic subduction along the western hellenic subduction zone |
| url | http://hdl.handle.net/1721.1/85853 https://orcid.org/0000-0002-6485-0026 |
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