Seismic Regionalization, Signal Detector and Source Locator
Abstract
This class of problems represents a permanent challenge to seismologists despite much ingenuity and efforts over the last decades. The persistent epicenter location problem is illustrative; now as in the 1960 a main research strategy for improved accuracy is tied to an elaborate system of P- and S- travel time and station corrections. For local ranges results would hardly be optimum since the major problem here is that of proper identifying S-phases in largely "chaotic" recordings besides ignoring the information potential in the waveforms themselves. In the simplifying case of spatially stationary signals from a specific mine or quarry it has been demonstrated previously by Fedorenko et al. (1998, 1999) that exploiting waveform information from a network of stations or a single 3-comp. station result in enhanced epicenter locations and source type identification. Corresponding analysis in case of earthquake waveforms are more complex since source type and locations are not necessarily spatially stationary; in essence earthquake records are "deformed" as a function of epicenter distance. The first problem encountered was surprisingly lack of adequate data; for detector research long time intervals are needed while for location station spacing should for a start be between say 15 to 60 km. Instead of wasting much time on local network records, often of poor quality, we deployed our own seismograph network using geophones as seismometers and preamplifier and A/D-converter of our design. Also, our 3-component instrument was tested through joint operation and site sharing with a Kinemetrics Ranger station - not clear which instrument had the best performance. Data transfer often proves to be ruinous in local network operation but not so for us; we simply launched a "school" project with sensor installations in school yards including access to the school's Internet so free data transfer to server in our office.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 2001
- Accession Number
- ADA527331
Entities
People
- Eystein S. Husebye
- Yuri V. Fedorenko
Organizations
- University of Bergen