Development of Automated Moment Tensor Software at the Prototype International Data Center
Abstract
We are porting to the Prototype International Data Center (PIDC) seismic moment tensor software used at the Berkeley Seismological Laboratory for the routine monitoring of earthquake strain release (Romanowicz et al., 1993; Pasyanos et al., 1996). The moment tensor software also forms an integral core in our efforts to automatically and rapidly characterize strong shaking from large earthquakes using information derived from sparse regional distance network (e.g. Dreger and Kaverina, 2000). Two separate moment tensor methodologies are employed: a surface wave spectral amplitude and phase method and a three component inverse method. For the purpose of screening seismic events for nuclear treaty monitoring the automatic determination of seismic moment tensors can contribute on several levels. First, seismic moment tensors provide robust estimates of the scalar seismic moment, which is a component of some regional distance discrimination techniques, or is a necessary source parameter for their calibration (e.g. Woods et al., 1993; Patton and Walter, 1993, Mayeda et al., 1993; Mayeda and Walter, 1996). Second, the seismic moment tensor inversions provide estimates of source depth. Finally, the seismic moment tensor may be used to examine the degree that seismic radiation deviates from a pure double-couple model of a tectonic event (e.g. Dreger et al., 2000), thereby providing an additional screening capability. Automated procedures are needed to be able to handle the annual numbers of low magnitude events on a global scale. The objective of our project is to port an automatic system for the analysis of seismic events of Mw is greater than or equal to 5.5 on a global scale with the goal of refining capabilities to estimate seismic moment tensors for seismic events down to Mw=4.5. We will present the results of a performance test of the methods using M(W) is greater than 4.5 data recorded by the IMS primary network for a three-month period.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 05, 2001
- Accession Number
- ADA527095
Entities
People
- Barbara Romanowicz
- Douglas S. Dreger
- G. Clitheroe
- Jeffry Stevens
- Peppy Hellweg
Organizations
- University of California, Berkeley