[S-SS07] Environmental Seismology: from deep earth to surface process

[SSS07-06] Unveiling Climate-Driven Ocean Wave Activity in the North Sea Region Through a Decade of Storm Observations Using Seismic Arrays

★Invited Papers

*Yichen Zhong¹、Chen Gu¹、Michael Fehler²、German Prieto³、Peng Wu¹、Zhi Yuan¹、Zhuoyu Chen¹、Jiawei He¹ (1.Tsinghua University、2.Massachusetts Institute of Technology、3.Universidad Nacional de Colombia)

キーワード：ambient noise, storm, seismic array, ocean, climate

Climate events may induce abnormal ocean wave activities, that can be detected by seismic array on nearby coastlines. We collected long-term continuous array seismic data in the coastal areas of the North Sea, conducted a comprehensive analysis to extract valuable climate information hidden within the ambient noise. Through long-term spectral analysis, we identified the frequency band around 0.2Hz, which appears to be associated with swell waves within the region, exhibiting a strong correlation with the local significant wave height (SWH). Additionally, we identified the ambient noise induced by storms during the last decade. Through spectral analysis of 10 years of data, we observed a slight decreasing trend in storm induced ambient noise intensity. This phenomenon may be attributed to the weakening temperature gradient of the Icelandic Low cyclone induced by global warming, coupled with the topographical characteristics of the North Sea region, which collectively contribute to the reduction in storm intensity in this area. Further analysis revealed a significant correlation between the power spectral density (PSD) of swell signals and the North Atlantic Oscillation (NAO) index, supporting this hypothesis. Our findings highlight the potential of seismic array data for monitoring ocean wave dynamics and provide new observational evidence for understanding the impacts of climate change on regional marine processes.