Observations and modelling of rotational signals in the P-Coda: constraints on crustal scattering

Abstract

In addition to three classical components (vertical, N-S, and E-W) of ground translations recorded by broadband seismometer, the vertical component of earthquake induced rotational ground motions is consistently measured by a ring laser sensor located in Wettzell, SE Germany. Significant rotational motions in the P coda of tele-seismic signals are either directly visible or can be inferred through the investigation of cross-correlation between transverse acceleration and vertical rotation rate. Theoretically, in spherically symmetric isotropic media we should not observe a vertical component of rotations before the onset of SH waves. Possible causes for the observed rotations in the P coda are: (1) tilt – ring laser coupling; (2) anisotropy; (3) topographic scattering; and (4) P-SH scattering in the crust. Here we show that P-SH scattering in the 3D random crust can explain the observations and allow us to constrain crustal scattering properties.

BibTeX
@article{id1309,
  author = {Pham, D. N.  and Igel, H. and Wassermann, J. and K\"aser, M. and de la Puente, J. and Schreiber, U.},
  doi = {10.1785/0120080101},
  journal = {BSSA},
  language = {en},
  number = {2B},
  pages = {1315-1332},
  title = {Observations and modelling of rotational signals in the P-Coda: constraints on crustal scattering},
  volume = {99},
  year = {2009},
}
EndNote
%O Journal Article
%A Pham, D. N. 
%A Igel, H.
%A Wassermann, J.
%A Käser, M.
%A de la Puente, J.
%A Schreiber, U.
%R 10.1785/0120080101
%J BSSA
%G en
%N 2B
%P 1315-1332
%T Observations and modelling of rotational signals in the P-Coda: constraints on crustal scattering
%V 99
%D 2009