Testing robust inversion strategies for three-dimensional Moho topography based on CELEBRATION 2000 data

Abstract

S U M M A R YIn this paper, we present results of the 3-D tomographic modelling of the crustal structure and Moho topography applied to data recorded in SE Poland during the CELEBRATION 2000 seismic experiment. The target area covers ca. 500 km × 500 km and represents a complex geological setting from old Precambrian platform (East European Craton, EEC), through the crustal blocks (terranes) that form the Trans-European Suture Zone, to the young Alpine orogen-the Carpathians. We test two different inversion strategies using two different algorithms: (i) coupled inversion of P g and P m P arrivals to constrain both the crustal velocities and the Moho depths; (ii) decoupled inversion of P m P arrivals only using previously obtained smooth 3-D crustal velocity model. The coupled inversion of 11 700 P g and 3100 P m P arrivals results in a much smoother crustal velocity field than the one previously obtained by inversion of first arrivals only. Also, the obtained Moho structure is much smoother than the Moho map compiled from the existing 2-D models. Decoupled inversion of the P m P reflections provides Moho structure comparable in resolution to the compiled map. Synthetic tests indicate that with our data set we are able to resolve larger than 100-km-size Moho structures. The modelled Moho is shallowest in the area of the Upper Silesian Block (ca. 32 km), then it is deepening by ca. 10 km over 100-km-wide zone along the margin of the EEC and finally it reaches up to 48 km depth in the area of the EEC. Our favoured strategy for modelling large refraction/wide-angle reflection data set consists of derivation of a smooth crustal velocity model by a first-arrival tomography and then complementing this model by a decoupled inversion of P m P reflections in order to constrain minimum-structure Moho topography.

Lithospheric structure of Central Europe: Puzzle pieces from Pannonian Basin to Trans‐European Suture Zone resolved by geophysical‐petrological modeling

“…Five main and eight additional profiles were shot between the SE part of the EEC, Bohemian Massif, and the Pannonian Basin‐Western Carpathian region. We used these data and profiles to constrain our model: CEL01, CEL02, CEL03, CEL04, CEL05, CEL06, CEL09, CEL10, CEL11, CEL12, CEL13, CEL14, CEL21, and 3‐D tomography model [ Grad et al ., ; Hrubcová et al ., , ; Janik et al ., , ; Malinowski et al ., , , ; Środa et al ., ]. ALP 2002 experiment followed the CELEBRATION 2000, covering the Eastern Alps and the adjacent areas of Hungary, Slovenia, Croatia, and the Czech Republic. Seismic data were collected along 14 profiles of total length of 4313 km.…”

“…Five main and eight additional profiles were shot between the SE part of the EEC, Bohemian Massif, and the Pannonian Basin-Western Carpathian region. We used these data and profiles to constrain our model: CEL01, CEL02, CEL03, CEL04, CEL05, CEL06, CEL09, CEL10, CEL11, CEL12, CEL13, CEL14, CEL21, and 3-D tomography model Hrubcová et al, 2005Hrubcová et al, , 2008Janik et al, 2005Janik et al, , 2009Malinowski et al, 2005Malinowski et al, , 2008Malinowski et al, , 2009]. 3.…”

Crustal structure of the Western Carpathians and Pannonian Basin: Seismic models from CELEBRATION 2000 data and geological implications

“…1). The ultimate goal of this series of experiments is a consistent 3D interpretation of all existing data in the vast area covered by them (e.g., Malinowski et al, 2008Malinowski et al, , 2009.…”

“…Additionally, a new model for the short profile CEL28, located in eastern Hungary, is presented here. Other papers employing the data from these profiles focused on seismic anisotropy in the upper-middle crust (Środa, 2006) and 3D seismic tomography (Malinowski et al, 2008(Malinowski et al, , 2009.…”

Models of the Earth’s crust from controlled-source seismology — Where we stand and where we go?

“…To overcome these limitations, some authors advocate prior ray-tracing modeling to identify phases (e.g., Majdański et al 2006), but it is somehow contradictory to the very idea of multi-layer tomography as a step forward to skip trial-and-error type modeling. Existing multilayer-tomography software packages (Hobro et al 2003, Trinks et al 2005 are not very efficient because of the relatively slow forward solution, however, as shown by Malinowski et al (2009), they can be used to model large 3D WARR survey.…”