5:15 PM - 7:15 PM
[SSS12-P16] Efforts to improve P-wave focal Mechanism Analysis and CMT Analysis at the Japan Meteorological Agency
Keywords:P-wave focal mechanism analysis, CMT analysis
The Japan Meteorological Agency (JMA) has been conducting P-wave focal mechanism analyses and CMT analyses for earthquakes of magnitudes greater than those defined for each region in and around Japan (https://www.data.jma.go.jp/eqev/data/mech/index.html). We are currently working to improve these automated analyses in order to obtain more accurate moment magnitudes and mechanism solutions more quickly.
For the P-wave focal mechanism analysis, the results of the automated analysis are verified by the on-site engineer, and the person in charge of the analysis further verified the results, determines the solution, and registers it. Although the JMA currently uses Nakamura (2002) method (AR-AIC method) to automatically pick first P-wave motion polarities, but we are developing a new method that uses deep learning to identify the P-wave first motion polarity in order to further improve the accuracy.
Current CMT analyses in the JMA use the PREM velocity structure model (Dziewonski and Anderson, 1981), which sometimes causes problems such as phase shift of only the transverse component and inversion of the obtained focal mechanism. We are examining the verify the accuracy of the analysis when the velocity structure model is changed from the PREM to the JMA2001 (Ueno et al., 2002). In this presentation, we will report on these efforts.
For the P-wave focal mechanism analysis, the results of the automated analysis are verified by the on-site engineer, and the person in charge of the analysis further verified the results, determines the solution, and registers it. Although the JMA currently uses Nakamura (2002) method (AR-AIC method) to automatically pick first P-wave motion polarities, but we are developing a new method that uses deep learning to identify the P-wave first motion polarity in order to further improve the accuracy.
Current CMT analyses in the JMA use the PREM velocity structure model (Dziewonski and Anderson, 1981), which sometimes causes problems such as phase shift of only the transverse component and inversion of the obtained focal mechanism. We are examining the verify the accuracy of the analysis when the velocity structure model is changed from the PREM to the JMA2001 (Ueno et al., 2002). In this presentation, we will report on these efforts.