Accurate epicenter locations in the vicinity of the seamount by using BBOBS array data

• Published in: Journal of volcanology and geothermal research 2024-11, Vol.455, p.108186, Article 108186
• Main Authors: Aoyama, Tetsuya, Takeuchi, Nozomu, Aoki, Yosuke
• Format: Article
• Language: English
• Subjects: BBOBS; Dike intrusion; Double difference; Submarine volcanoes; Waveform data analysis
• ISSN: 0377-0273
• DOI: 10.1016/j.jvolgeores.2024.108186

A Mw = 6.4 earthquake, possibly related to submarine volcanism, occurred on October 23, 2006, in the vicinity of Monday Seamount, located in the Izu-Bonin-Mariana arc. Despite the size of the earthquake, the precise location of aftershocks is intractable with the routine data processing because of poor station coverage and complex waveforms traversing the oceanic lithosphere. This study overcomes these problems by using the Broadband Ocean Bottom Seismometer (BBOBS) array data with better azimuthal coverage and by developing new methods to detect the P-wave arrival time to locate the aftershocks precisely. Most of the relocated epicenters are located in the rift zone next to the edifice of the seamount. We interpret this pattern as the seismic activity induced by stress perturbation due to the dike intrusion. •We developed a new method to locate epicenters, giving sparsely distributed seismic sites.•We applied the new method to a Mw = 6.4 earthquake and aftershocks that are possibly related to submarine volcanism of Monday Seamount, Izu-Bonin-Mariana arc.•The majority of the newly obtained epicenters are distributed are in the rift zone near the edifice of Monday Seamount.•The aftershock distribution implies dike intrusion to the west of Monday Seamount.