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- Title
A Single‐Station Method for Seismic Detection of Slow Earthquakes: Applications to Japan and the Mexican Subduction Zone.
- Authors
Masuda, Koki; Ide, Satoshi
- Abstract
Slow‐earthquake signals are generally smaller than or comparable to noise levels at almost all seismological frequencies. Comprehensive detection of these events requires continuous waveforms from many stations, but such data are not always available, even in regions with high slow‐earthquake activity. We therefore need a simple and stable detection method that is also applicable to regions with sparse seismic observation networks to truly advance our understanding of slow earthquakes. Here, we utilize the proportionality between the seismic energy rate and seismic moment rate of slow earthquakes to develop a slow‐earthquake detection method using broadband waveforms from a single station. We introduce the method and estimate its performance using continuous waveform data in Japan. The new method only detects events when the tectonic tremors occur near the station, for example, 89.1% of the detections have corresponding tectonic tremor activities within 60 km, which suggests that the false‐positive rate is low. We then apply it to waveform data from the Guerrero, Oaxaca, and Jalisco regions along the Mexican subduction zone. The results for the Guerrero and Oaxaca regions are largely consistent with the geodetic and seismological results from a previous study. We also detect many events in the Jalisco region using a permanent station and provide the first seismological report of long‐term slow‐earthquake activity in this region. Some of the large‐scale slow‐earthquake activity that is detected in this study is consistent with the timings of known slow‐slip events, which implies that other unknown slow‐slip events may have occurred when we detected many events. Plain Language Summary: A relatively new type of tectonic phenomenon, slow earthquakes, has been found in many regions worldwide and investigated in detail due to their potential importance in better understanding the preparation process of large earthquakes. We can detect slow earthquakes relatively comprehensively in regions with dense observation networks, such as Japan and the west coast of the United States. However, these regions comprise a small part of the Earth's surface, and we have limited information on slow‐earthquake activity in many other regions. The purpose of this study is to expand our capability to detect and analyze slow‐earthquake activity by developing a method that can detect slow earthquakes using data from a single seismic station. The slow‐earthquake detections via our new method are consistent with previous study results in Japan and Mexico. Furthermore, we have successfully conducted the first long‐term analysis of seismological slow‐earthquake activity in the Jalisco region of Mexico. Key Points: Development of a new method to detect slow earthquakes using waveform data from a single seismic stationPresented slow‐earthquake detection is consistent with previous findings in Japan and MexicoFirst long‐term seismological analysis of slow earthquakes in the Jalisco region of Mexico
- Subjects
JALISCO (Mexico); JAPAN; MEXICO; EARTHQUAKES; SURFACE of the earth; SUBDUCTION zones; SEISMIC networks; SENDAI Earthquake, Japan, 2011
- Publication
Journal of Geophysical Research. Solid Earth, 2023, Vol 128, Issue 11, p1
- ISSN
2169-9313
- Publication type
Article
- DOI
10.1029/2023JB027311