Borehole Seismic Observations from the Chicxulub Impact Drilling: Implications for Seismic Reflectivity and Impact Damage

We conducted a vertical seismic profile (VSP) in the borehole of International Ocean Discovery Program/International Continental Scientific Drilling Program Expedition 364 Site M0077 to better understand nature reflectivity and situ properties associated with Chicxulub impact structure peak ring. Extraction up-going wavefield from VSP shows that strong reflection event imaged data results discontinuities elastic impedance Z (the product density wave speed) at top bottom zone hydrothermally altered melt-bearing polymict breccia (suevite) are characterized by anomalously low Z. Below this carbonate/suevite event, upgoing is chaotic, indicating high levels scattering suevites underlying melt rocks shocked granitoids ring, contrast clear coherent reflections throughout overlying Cenozoic sediments. extract shear speeds, which, together those provided complementary sonic log densities core scanning, allowed determination VP/VS Poisson's ratio v. These values relative comparable terrestrial lithologies. also calculate variety damage parameters for disrupted ring granitoids. may assist linking observations shock necessary calibrate current models be useful assessing fracturing within major fault zones.