## Inversion for parameters of tensile earthquakes

**Vaclav Vavrycuk**
### Summary

The tensile source model generalizes the shear source model by assuming
that the slip vector can be arbitrarily oriented with respect to the fault
and is not constrained to lie within the fault plane. The proposed inversion
for the parameters of tensile sources is based on the evaluation of
the isotropic (ISO), compensated linear vector dipole (CLVD), and
double-couple (DC) components in seismic moment tensors. The most significant
parameters inverted are the *lambda*/*mu* ratio at the fault
(denoted as the *kappa*
parameter) and the inclination alfa of the slip vector from the fault.
The *kappa* parameter is significant for discriminating noisy moment tensors
of shear earthquakes from those of tensile earthquakes. The inclination alfa
can be accurately determined from the DC component in the moment tensor
because the DC component rapidly decreases with increasing alfa. For example,
the inclination of 20° causes DC being ~50-60% only. The inversion
is applied to earthquakes which occurred in January 1997 in West Bohemia,
Czech Republic. It is shown that some of these earthquakes display tensile
faulting. The *kappa* parameter is ~0.1. The inclination of the slip from
the fault attains values of up to 20°. This inclination is a result
of tensile traction and reduced shear traction along the fault and
high-fluid pressure in the region.

### Whole paper

The scanned reprint is available in
PDF 300dpi (2764 kB !).

*J. geophys. Res.,*, **106 B** (2001), 16339-16335.

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