DETERMINATION OF THE ISOTROPIC COMPONENT OF THE 1994 BOLIVIA DEEP EARTHQUAKE

We determine the isotropic component of the moment tenser of the 1994 Bolivia deep earthquake using various seismic waves, including body wa ves, surface waves, and normal mode data, in the period band between 2 0 s and 1000 s. We carefully investigate whether the isotropic compone nt can be obtained independently from the other components by checking the correlation matrices. We show that it is possible to obtain a pre cise estimate of the isotropic component by using normal mode data in the period band between 550 and 1000 s. We find that the Bolivia earth quake did not have a significant isotropic component in this period ba nd.