Geoscience Research

7-21

Authors: Moidaki M., Gao S.S., Liu K.H., Abdelsalam M.G., Hogan J.P., Atekwana E

Receiver functions from numerous teleseismic earthquakes recorded at 26 broadband seismic stations within the New Madrid Seismic Zone (NMSZ) were analyzed to map crustal thickness, Poisson’s ratio and Moho thickness within and around the NMSZ. The results show that the average crustal thickness of the stations within the Mississippi embayment is 33.4±0.28 km. The crust thins to about 25.5±1.09 km at OXF and thickens to about 43.3±0.12 km at PLAL. In the Mazatazal Belt, the crust varies from 30.2±0.14 to 53.1±0.29 km thick. However, the crust is thicker at WCI (53.1±0.29 km). There is a dramatic change in crustal thickness between the cratonic stations and stations within the Mississippi embayment. Our results from the Mazatzal belt are comparable to other Proterozoic and Archean shields that include reasonably well determined Moho depths, mostly based on receiver functions. The average crustal thickness for all shields is 39 km, while the average for Proterozoic shields is 40 km, and the average for Achaean shields is 38 km. We observed a dramatic change in crustal thickness from stations with the Mississippi embayment over a very short distance.