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Automatic seismic event recognition and later phase identification for broadband seismograms

Tong, Cheng and Kennett, Brian L. N. (1996) Automatic seismic event recognition and later phase identification for broadband seismograms. Bulletin of the Seismological Society of America, 86 (6). pp. 1896-1909. ISSN 0037-1106.

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Knowledge of the patterns of frequently observed seismic phases associated with specific distances and depths have been well developed and applied by seismologists (see, e.g., Richter, 1958; Kulhánek, 1990). However, up till now, the expertise of recognizing seismic event patterns for teleseisms has not been translated into automatic processing procedure. A new approach is developed to automate this kind of heuristic human expertise in order to provide a means of improving preliminary event locations from a single site. An automatic interpretation system exploiting three-component broadband seismograms is used to recognize the pattern of seismic arrivals associated with the presence of a seismic event in real time accompanied by an identification of the individual phases. For a single station, such a real-time analysis can be used to provide a preliminary estimation of the location of the event. The inputs to the interpretation process are a set of features for detected phases produced by another real-time phase analyzer. The combinations of these features are investigated using a novel approach to the construction of an expert system. The automatic system exploits expert information to test likely assumptions about phase character and hence epicentral distance and depth. Some hypotheses about the nature of the event will be rejected as implausible, and for the remainder, an assessment is given of the likelihood of the interpretation based on the fit to the character of all available information. This event-recognition procedure provides an effective and feasible means of interprating events at all distances, and characterizing information between hundreds of different possible classes of patterns even when the observation is incomplete. The procedure is based on “assumption trees” and provides a useful tool for classification problems in which a number of factors have to be identified. The control set of expert knowledge used in testing hypotheses is maintained separately from the computational algorithm used in the assumption search; in consequence, the information base can be readily updated.

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Additional Information:© 1996 Seismological Society of America. Manuscript received 5 December 1995. We would like to thank Jan Weekes for sharing her many years experience in the recognition of seismic phases and seismogram interpretation, which have helped to shape the automatic procedures developed in this article. This work was supported in part by Grant F49620-94-0110 from the U.S. Air Force Office of Scientific Research.
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Air Force Office of Scientific Research (AFOSR)F49620-94-0110
Issue or Number:6
Record Number:CaltechAUTHORS:20140806-103328412
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Official Citation:Cheng Tong and Brian L. N. Kennett Automatic seismic event recognition and later phase identification for broadband seismograms Bulletin of the Seismological Society of America, December 1996, v. 86, p. 1896-1909
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48066
Deposited By: Tony Diaz
Deposited On:06 Aug 2014 17:58
Last Modified:03 Oct 2019 06:59

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