This research work focuses on attaining optimal parameter settings for precise identification of seismic signals at the output of large ring laser gyro through the application of the STA/LTA trigger algorithm. Lately, the sensitivity of rotations has been improved by at least 5 orders of magnitude because of significant upscaling of very large perimeter ring laser gyroscopes. This process in rotational sensors technology brought about the successful detection of rotational signals resulting from earthquakes several thousand of kilometers away. The identification of seismic signals at the output of the large ring laser Gyro may be carried out using the trigger algorithm. As soon as an assumed seismic event is detected, recording and storing of all incoming signals begins. It stops after trigger algorithm 'declares' the end of the seismic signal. The ‘short-time-average through long-time-average trigger' (STA/LTA) is the most widely used algorithm in weak-motion seismology. It constantly calculates the average values of the absolute amplitude of a seismic signal in consecutive moving- time windows. All records, along with those falsely triggered, must be inspected. The completeness of the event records is checked (seismic noise, the P arrivals, the coda waves), and the causes of the false triggers are analyzed. After the evaluation is completed, the parameters are modified consistent with its findings and the new settings archived for documentation purposes. By repeating this process one will progressively discover the satisfactory parameter setting.

Date Published: 13 September 2018
PDF: 11 pages
Proc. SPIE 10764, Earth Observing Systems XXIII, 107641M (13 September 2018); doi: 10.1117/12.2320614

Published in SPIE Proceedings Vol. 10764:
Earth Observing Systems XXIII
James J. Butler; Xiaoxiong (Jack) Xiong; Xingfa Gu, Editor(s)