Imaging of the Crust and Moho beneath Oklahoma using Receiver Functions and Pn Tomography; with Emphasis on the Southern Oklahoma Aulacogen



Journal Title

Journal ISSN

Volume Title



US TransportableArray seismic data over the Southern Oklahoma Aulacogen and surrounding region was downloaded from the Incorporated Research Institutions for Seismology (IRIS) to map lithosphere boundaries including the Mohorovičić discontinuity (Moho) and Hales discontinuity (Hales), along with creating crustal velocity models. Water-level (i.e. prewhitening) deconvolution in the frequency domain was used to filter out the bad stations. The good stations were further improved by cross-correlating and stacking the vertical component of nearby stations (i.e. beamforming) to reduce the need for prewhitening and improve the signal-to-noise ratio in the receiver functions. These stacked move-out corrected receiver functions (SMOCRF) were used to interpret depth and Vp/Vs ratios of features in the lithosphere including the upper, middle, and lower crustal layers as well as the Moho and Hales discontinuity, and related these to the geology of Southern Oklahoma Aulacogen and its subsequent features. Also the data was used to pick Pn arrival times at each station and then complete straight ray Pn tomography to better see the geologic features expressed on the Moho. The Moho depth along the Southern Oklahoma Aulacogen correlates well with the previous geological and geophysical work done from the literature with deep signature beneath the Amarillo-Wichita uplift, and general shallowing trend from west to east across the region. There is evidence of an iron depleted Moho beneath the aulacogen. The Pn tomography results show the Southern Oklahoma Aulacogen represented along the Moho by a linear low-velocity feature. The lower velocity along the uplift may be due to an iron depleted area of old Moho that has depressed the mantle and thus increased Pn travel time. My recommendation is to follow-up with a longer time period study over a the entire area of the central to west continent thus incorporating larger offsets between earthquake and event as well as many more ray path directions over the entire area.