Constraining crustal structure in the presence of sediment: a multiple converted wave approach. Issue 1 (2nd July 2019)

• Record Type: Journal Article
• Authors: Cunningham, Erin; Lekic, Vedran
• Is Part Of: Geophysical journal international. Volume 219:Issue 1(2019)
• Page Start: 313
• Page End: 327
• Publication Date: 2019-07-02
• Subjects: Time-series analysis -- Body waves -- Crustal imaging -- Site effects; Geophysics -- Periodicals; 550
• DOI: 10.1093/gji/ggz298
• Languages: English
• ISSNs: 0956-540X

Abstract

SUMMARY: Receiver functions are sensitive to sharp seismic velocity variations with depth and are commonly used to constrain crustal thickness. The H – κ stacking method of Zhu & Kanamori is often used to constrain both the crustal thickness ( H ) and${V_P}$ /${V_S}$ ratio ($\kappa $ ) beneath a seismic station using P-to-s converted waves (Ps). However, traditional H –κ stacks require an assumption of average crustal velocity (usually${V_P}$ ). Additionally, large amplitude reverberations from low velocity shallow layers, such as sedimentary basins, can overprint sought-after crustal signals, rendering traditional H –$\ \kappa $ stacking uninterpretable. We overcome these difficulties in two ways. When S -wave reverberations from sediment are present, they are removed by applying a resonance removal filter allowing crustal signals to be clarified and interpreted. We also combine complementary Ps receiver functions, Sp receiver functions, and the post-critical P -wave reflection from the Moho (SPm p) to remove the dependence on an assumed average crustal${V_P}$ . By correcting for sediment and combining multiple data sets, the crustal thickness, average crustal P -wave velocity and crustal${V_P}$ /${V_S}$ ratio is constrained in geological regions where traditional H –$\ \kappa $ stacking fails, without making an initial P -wave velocity assumption or suffering from contamination by sedimentary reverberations.