Topography of the 410 and 660 km discontinuities beneath the Korean Peninsula and southwestern Japan using teleseismic receiver functions

• Published in: Journal of geophysical research. Solid earth 2014-09, Vol.119 (9), p.7245-7257
• Main Authors: Lee, Sang-Hyun, Rhie, Junkee, Park, Yongcheol, Kim, Kwang-Hee
• Format: Article
• Language: English
• Subjects: CCP stacking; Discontinuity; Geologic depressions; Geophysics; Heterogeneity; Korean Peninsula; Latitude; Low temperature; Mantle; Mathematical models; Peninsulas; Receivers; Seismology; Slabs; subducting slab; teleseismic receiver function; Topography; Upper mantle; upper mantle discontinuities; Water content
• ISSN: 2169-9313; 2169-9356
• DOI: 10.1002/2014JB011149

Topography of the 410 and 660 km seismic upper mantle discontinuities beneath the Korean Peninsula and southwestern Japan were determined using teleseismic receiver functions. P receiver functions were migrated from delayed times to corresponding piercing (conversion) points of P‐to‐S converted phases, using one‐dimensional (1‐D) and three‐dimensional (3‐D) models. Receiver functions were then stacked using Common Conversion Point (CCP) techniques, to enhance signal‐to‐noise ratios and thereby reduce uncertainty (noise). The 410 and 660 km discontinuities were clearly imaged, as positively valued amplitude peaks of CCP stacked receiver functions in the study area. Topographic variations were roughly consistent with the low temperature of the subducting Pacific Plate. However, the complex structure of the subducting Pacific Plate produced distinct changes of upper mantle discontinuities, which cannot be explained by temperature variations alone. Depression of the 410 km discontinuity, observed in a wide region extending from the Korean Peninsula to Kyushu Island, may be related to trench rollback history. Furthermore, the topography of the 660 km discontinuity varies significantly with latitude. At latitudes higher than 38°N, its depth remains unchanged, despite the presence of the stagnant slab, while significant depression has been observed at latitudes below 36°N. This may have been caused by differences in the angles of subduction of the Japan slab and the Izu‐Bonin slab. However, heterogeneity of the water content of slabs may also have contributed to this topographical difference. Key Points The 410 and 660 km seismic discontinuities beneath the Korea and SW Japan are imagedThey are affected by various factors as well as temperature of the slab