Japan Geoscience Union Meeting 2025

Presentation information

[J] Poster

S (Solid Earth Sciences ) » S-TT Technology & Techniques

[S-TT41] Seismic monitoring and processing system

Fri. May 30, 2025 5:15 PM - 7:15 PM Poster Hall (Exhibition Hall 7&8, Makuhari Messe)

convener:Yusuke Tomozawa( KAJIMA Corporation), Hisahiko Kubo(National Research Institute for Earth Science and Disaster Resilience)

5:15 PM - 7:15 PM

[STT41-P03] Detection for normal-like abnormal records observed with STS-2 seismometer

*Tomotsugu Watanabe1, Hiroshi Takenaka1 (1.Okayama University )

Keywords:seismic motion, broadband seismometer

We propose a method for detecting normal-like abnormal waveforms observed with STS-2 seismometer. While a lot of waveforms are recorded at the seismic station and widely exploited by many studies, it is hard to manually check whether these data are correct. We found the anomalous waveforms recorded by the STS-2 broadband seismometer of JMA. In this study, we demonstrate that these waveforms can be illuminated easily by plotting their 3-D particle motion and viewing their spatial distribution carefully.

Figure 1, for example, denotes 20-minute three-component waveforms and their particle motion recorded at Ikenosawa JMA station in Minamidaito Island, Okinawa Prefecture of the Mw6.8 event occurring at 5:23 on 29 April 2017 (JST) in Mindanao, southern Philippines. Although these waveforms (Fig. 1a) seem to be normal-like shapes, Fig. 1b and c show that their motions appear to follow a certain plane. We confirm that such abnormal distribution including both seismic events and noises has been recorded with similar characteristics up to the present day. Our concept may be a useful way not only for analysing the seismic waveforms but also exploiting the ambient noise based on seismic interferometry and monitoring the condition of the seismometer.

Acknowledgements: We used the STS-2 records observed at JMA station downloaded from IRIS and Hi-net (NIED) websites. We would like to thank the organizations involved in opening the data to the public. This study was partially supported by JSPS KAKENHI (B) Grant Number JP23K22582.