Body and Surface Wave Modeling of Observed Seismic Events
Abstract
The major accomplishments during the first four-year-period are summarized under the categories of (1) Application of Lunar Inversion Theory, (2) Seismic Source Theory and (3) Synthetic Body and Surface Wave Modeling of Observed Seismic Events. The details can be found in previous technical reports under the contract. In Section III, a multipole expansion of the divergence and rotations of the linear displacement field from an arbitrary source is used in a multilayer formulation to obtain teleseismic body waves. As long as the expansion is obtained in a homogeneous region about the source, the source can be extremely complicated. The technique has been used in other contracts for nonlinear finite difference simulations of stick-slip earthquake faulting and an explosion in an axisymmetric finite length tunnel. In Section IV, both generalized ray theory and matrix techniques were used to calculate synthetic body wave seismograms for a point source in a layered elastic medium. Both methods are found to be equivalent and complementary for various model calculations. Ray theory has the advantage of giving a direct physical interpretation to observed phases. Matrix techniques, while exact in terms of including all multipoles, give little insight into the model, but serves as a check on the dominant phases needed in the ray calculations. In Section V, a data set of forty-one moderate to large earthquakes were used to derive scaling rules for kinimatic fault models.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 07, 1976
- Accession Number
- ADA038077
Entities
People
- David G. Harkrider
- Donald V. Helmberger
Organizations
- California Institute of Technology