Extraction of Annual Variation Information and Determination of Prediction Indicators for the Horizontal Tilt Inclination Observation Data at Linfen Based on S-transform
Extraction of Annual Variation Information and Determination of Prediction Indicators for the Horizontal Tilt Inclination Observation Data at Linfen Based on S-transform
The monitoring capability and data seismogenic ability of the Linfen Station's horizontal pendu-lum have attracted much attention over the years.In order to advance the application of long-term periodic variations analysis in the data of the horizontal pendulum at Linfen Station,this study utilized a method for separating and extracting information on the long-term periodic variations based on S-transform time-frequency analysis.This method employed a bidirectional asymmetric threshold strategy,combined with R-value scoring and the Molchan diagram method to establish a predictive index for the long-term periodic variations in the east-west measurement of the Linfen horizontal pendulum.The study provided the optimal threshold,forecast range,and forecast window for long-term signal changes(ANA)and short-term signal changes(ONA)for differ-ent seismic level ranges.The forecast efficiency R-value was greater than the R0 value,indicating high reliabili-ty.Specifically,the ANA index showed the best forecast efficiency for ML≥5 seismic events within 500 km.
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