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Estimating crustal thickness using SsPmp in regions covered by low‐velocity sediments: Imaging the Moho beneath the Southeastern Suture of the Appalachian Margin Experiment (SESAME) array, SE Atlantic Coastal Plain
Author(s) -
Parker Jr. E. Horry,
Hawman Robert B.,
Fischer Karen M.,
Wagner Lara S.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl070103
Subject(s) - geology , basement , seismology , mafic , travel time , reflection (computer programming) , geodesy , geomorphology , petrology , civil engineering , engineering , transport engineering , computer science , programming language
Deconvolved waveforms for two earthquakes ( M w : 6.0 and 5.8) show clear postcritical SsPmp arrivals for broadband stations deployed across the coastal plain of Georgia, allowing mapping of crustal thickness in spite of strong reverberations generated by low‐velocity sediments. Precritical SsPmp arrivals are also identified. For a basement in which velocity increases linearly with depth, a bootstrapped grid search suggests an average basement velocity of 6.5 ± 0.1 km/s and basement thickness of 29.8 ± 2.0 km. Corresponding normal‐incidence Moho two‐way times (including sediments) are 10.6 ± 0.6 s, consistent with times for events interpreted as Moho reflections on coincident active‐source reflection profiles. Modeling of an underplated mafic layer ( V p = 7.2–7.4 km/s) using travel time constraints from SsPmp data and vertical‐incidence Moho reflection times yields a total basement thickness of 30–35 km and average basement velocity of 6.35–6.65 km/s for an underplate thickness of 0–15 km.