Detecting the Oceanic Moho Using Teleseismic P‐Wave Coda Autocorrelations of Ocean Bottom Seismograph Records

Abstract Although active‐source seismic methods can image the oceanic Mohorovičić discontinuity (Moho) at high resolution, their high cost motivates passive approaches using OBS, for which receiver functions (RF) are often complicated by instrument tilt, azimuthal misalignment, sedimentary layers, and water‐column reverberations. Here we apply teleseismic P‐wave coda autocorrelation to hydrophone data from OBS to image the oceanic Moho. Compared with vertical‐component data, hydrophone data provide a simpler interpretation because they avoid P‐to‐S conversions and are dominated by reflected and transmitted P‐wave energy. By analyzing autocorrelation results from 22 long‐period and 24 short‐period stations in the NoMelt experiment, we identify a Moho reflection with a TwTT of ∼2.56 s and resolve lateral variations in crustal TwTT that are smoothed out in the radially averaged representations of global velocity models. Combined with previous studies and model tests, this longer‐than‐expected crustal TwTT suggests that a crust‐mantle transition zone may exist beneath the NoMelt region.