Modeling Regional Seismic Waves
Abstract
This research can be divided into two main topics: using the moment of regional Rayleigh waves and a regional magnitude based on the maximum amplitude of the shear wave train as a seismic discriminant and source retrieval from broadband regional seismograms. In section 1, we propose using the ratio of M sub L (local magnitude) to M sub O (Scalar Seismic Moment) as a regional discriminant analagous to the teleseismic discriminant using the m sub b; M sub s ratio. We applied this criterion to a data set of 299 earthquakes and 178 explosions and found that this ratio appears to be diagnostic of source type. This method does require the determination of regional crustal models and path calibrations from master events or by other means. In section 2, we develop and test a method of relocation and source characterization of small earthquakes using one modern regional station. First we model teleseismic body-waves of two events, which are used as masters. Short period depth phases, pP and sP, are used to establish the epicentral depth, and the events are relocated using calibrated stations and a mantle model derived for this region, TIP. The events moved upward by 12 and 31 kms, respectively. Secondly, these events can be used as 'masters' in the calibration of other systems, case-based event characterizations, etc.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 24, 1992
- Accession Number
- ADA267295
Entities
People
- David G. Harkrider
- Donald V. Helmberger
Organizations
- California Institute of Technology