Resolving the Sedimentary Basin Structure from Oklahoma with Local Receiver Function

Abstract:

The teleseismic receiver function is defined as the radial component of P wave being deconvoluted from the vertical component of the earthquakes with magnitude larger than 5.5 at teleseismic distances. It has successfully been applied in resolving the structure of the crust and upper mantle in many regions. The receiver function can also be used to determine the thickness of sedimentary basin. However the corner frequency of the P waves from the teleseismic events (M>5.5) is relatively low and the high frequency content in the teleseismic P waves is attenuated, thus, the teleseismic receiver function is usually not sufficient to reveal details of sedimentary basin structure. Instead, local small earthquake (~ M3) generates P waves of short duration waveforms with high frequency content, which can be used to calculate receiver functions (called local receiver function). As a case study, we study waveform data from local earthquakes in Oklahoma. We first explore feasibility of local receiver function for different magnitude, focal depth, epicentral distance, filtering band and time window length. After local receiver functions are computed, we search the best velocity model to fit the local receiver function waveforms with the Differential Evolution (DE) algorithm which is a global optimization method. We invert the sedimentary basin structure in Oklahoma and find that this method is suitable for other area for the sedimentary basin structure where local seismic waveforms are available.