TITLE AND SUBTITLE: Special Event Discrimination Analysis: The Texar Blind Test and Identification of the August 16, 1997 Kara Sea Event.

AUTHOR: Douglas Baumgardt

PERFORMING ORGANIZATION:
ENSCO, Inc.
5400 Port Royal Road
Springfield, VA 22152-2301

SPONSORING AGENCY:
Air Force Research Laboratory
29 Randolph Road
Hanscom AFB, MA 01731-3010

SUPPLEMENTARY NOTES: This research was sponsored by the Dept of Energy, Office of Non-Proliferation & National Security, Washington DC 20585

ABSTRACT: The International Monitoring System (IMS) for the Comprehensive Test Ban Treaty (CTBT) faces the serious challenge of being able to accurately and reliably identify seismic events in any region of the world. Extensive research has been performed in recent years on developing discrimination techniques which appear to classify seismic events into broad categories of source types, such as nuclear explosion, earthquake, and mine blast. This report examines in detail the problem of effectiveness of the regional discrimination procedures in the application of waveform discriminants to Special Event identification and the issue of discriminant transportability.

This report is divided into three parts:

1) INTRODUCTION

Talks about the challenges of reliably identifying seismic regions in any region of the world, and the techniques used in identifying the source of these quakes i.e. nuclear explosion, earthquake, mine blast.

Addressing an event that cannot be quickly identified using screening methods or "Special Event," is important, and would require more in-detail analysis.

2) A BLIND TEST OF SEISMIC EVENT DISCRIMINATION PROCEDURES FROM THE TEXAR CHALLENGE

This section presents the results of a blind-test study, arranged by Professor Eugene Herrin of Southern Methodist University, in which 20 events of unknown identity were recorded at the TEXAR array in souther Texas.

The study was to use the discrimination techniques in the Intelligent Seismic Event Identification System (ISEIS) to determine how many events could be identified.


3) CHARACTERIZATION OF THE AUGUST 16, 1997 KARA SEA EVENT

Presents the results of the Kara Sea event that occurred near the former Soviet test site at Novaya Zemlya. Because the ARCESS array was down at the time, there was little historical data to be used. However, KEV recorded data from nuclear explosions at Novaya Zemlya, which had similar site and propagation effects. Thus the two stations can be directly compared. Also consideration of a possible underwater explosion (explaining Kara) is pondered given that it was located offshore.