Location of Repository

Three-dimensional joint inversion of traveltime and gravity data across the Chicxulub impact crater

By P.M. Vermeesch, J.V. Morgan, G.L. Christeson, P.J. Barton and A. Surendra

Abstract

In 2005 an extensive new seismic refraction data set was acquired over the central part of the Chicxulub impact crater, allowing us to image its structure with much better resolution than before. However, models derived from traveltime data are limited by the available ray coverage and the nonuniqueness that is inherent to all geophysical methods. Therefore, many different models can fit the data equally well. To address these issues, we have developed a new method to simultaneously invert traveltime and gravity data to obtain an integrated model. To convert velocity to density, we use a linear relationship derived from measurements on core from the Chicxulub impact basin, thus providing a reliable conversion equation that is typical for lithologies of the central part of this crater. Prior to utilizing the inversion on the observed data, we have run a suite of tests to establish the optimum weighting between traveltime and gravity constraints, using a synthetic model of central crater structure and the real experimental geometry. These synthetic tests indicate which inversion parameters lead to the best recovery of subsurface structure, as well as which parts of the model are well resolved. We applied the method to all existing gravity data and to seismic refraction data acquired in 1996 and the new, higher-resolution seismic refraction data acquired in 2005. We favor the traveltime model wherever we have sufficient ray coverage and the joint model where we have no ray coverage

Topics: QE, GB
Year: 2009
OAI identifier: oai:eprints.soton.ac.uk:64288
Provided by: e-Prints Soton

Suggested articles

Preview

Citations

  1. (2006). 3-D seismic refraction traveltime tomography at a shallow groundwater contamination site,
  2. (2004). Chicxulub central crater structure: Initial results from physical property measurements and combined velocity and gravity modeling,
  3. (2006). Chicxulub: An analysis of new gravity data,
  4. (1980). Combined interpretation of gravity and seismic evidence—Formulation of problems, Izv. Akad. Nauk SSSR Fiz. Zemli(7), 95–100. Grieve,R.A.F.,P.B.Robertson,andM.R.Dence(1981),Constraintsonthe formation of ring impact structures, based on terrestrial data,
  5. (1988). Cooperative inversion of geophysical-data,
  6. (2004). Crustal structure of the southernmost Ryukyu subduction zone: OBS, MCS and gravity modelling,
  7. (2001). Deep crustal structure of the Chicxulub impact crater,
  8. dicke (2005), Is Ries crater typical for its size? An analysis based upon old and new geophysical data and numerical modeling, in Large Meteorite Impacts III, edited by
  9. (2008). Dynamic modeling suggests terrace zone asymmetry in the Chicxulub crater is caused by target heterogeneity,
  10. (1988). Finite-difference calculation of travel times,
  11. (1990). Finite-difference calculation of traveltimes in three dimensions,
  12. (2007). Frictional melting and complex crater collapse, paper presented at Bridging the Gap II, Can. Space Agency,
  13. (1994). Gravity and magnetic field modelling and structure of the Chicxulub crater,
  14. Grieve (2002b), Geophysical constraints on the size and structure of the Chicxulub impact crater, in Catastrophic Events and Mass Extinctions: Impacts and Beyond,
  15. (2002). Hydrocode simulations of Chicxulub crater collapse and peak-ring formation,
  16. (1989). Impact Cratering: A Geologic Process,
  17. (2008). Importance of pre-impact crustal structure for the asymmetry of the Chicxulub impact crater,
  18. (2000). Integrated gravity and wide-angle seismic inversion for two-dimensional crustal modelling,
  19. (2005). Joint inversion of first arrival seismic travel-time and gravity data,
  20. (2006). Joint inversion of MT, gravity, and seismic data applied to sub-basalt imaging, paper presented at 76th SEG Meeting,
  21. (2002). Joint inversion of refraction and gravity data for the three-dimensional topography of a sedimentbasement interface,
  22. (1982). LSQR: An algorithm for sparse linear equations and sparse least squares,
  23. (1998). Mapping Chicxulub crater structure with gravity and seismic reflection data, in Meteorites—Flux with Time and Impact Effects, edited by
  24. (2007). Modeling impact cratering in layered surfaces,
  25. (2000). Peak-ring formation in large impact craters: Geophysical constraints from Chicxulub,
  26. (1990). Regularisation of nonlinear inverse problems: Imaging the near-surface weathering layer,
  27. (1991). Seismic tomography constrained by Bouguer gravity-anomalies—Applications in western Washington,
  28. (2000). Sequential integrated inversion of refraction and wide-angle reflection traveltimes and gravity data for two-dimensional velocity structures,
  29. (2007). Stratigraphic uplift beneath the Chicxulub impact crater:
  30. (2008). Structural uplift beneath the Chicxulub impact structure,
  31. (2007). The effect of target properties on impact crater morphology—Comparison of craters on icy and silicate bodies, paper presented at Bridging the Gap II, Can. Space Agency,
  32. (2003). Three dimensional gravity field modeling of the Chicxulub impact crater,
  33. (1995). Three-dimensional finite-difference reflection times,
  34. (2000). Three-dimensional magnetic imaging of the Chicxulub crater,
  35. (1998). Three-dimensional seismic refraction tomography: A comparison of two methods applied to data from the Faroe Basin,
  36. (1999). Upper crustal structure of the Chicxulub impact crater from wide-angle ocean bottom seismograph data,

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.