High‐frequency seismic noise generated from breaking shallow water ocean waves and the link to time‐variable sea states
High‐frequency seismic noise generated from breaking shallow water ocean waves and the link to time‐variable sea states
复制标题
浅水海浪破碎产生的高频地震噪声及其与时变海况的联系
DOI：
--
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
D. Mallinson
中科院分区：
文献类型：
--
作者：
C. Poppeliers;D. Mallinson
近岸的破碎波已知会产生大量的高频（f > 5 Hz）能量。我们研究了地震能量谱与当地海况之间的相关性。我们在距离海岸约50米处部署了一台三分量宽带地震仪，并连续记录了约10天。我们的观察结果表明，在升高的海况下，以及可能在碎波区出现较大的破碎波时，波浪产生的地震能量的功率谱密度会向较低的频率和较高的谱幅值移动。这与大型倾翻式破碎机产生1-20 Hz声学次声的观察结果相似，表明次声的很大一部分在水/海底界面耦合成地震能量。根据我们的观察和以前的模型，它似乎是地震频谱是敏感的波的大小，但不是泥沙运动。无论如何，地震谱功率与海浪高度和周期的相关性表明，地震观测可用作当地海况的代理，这可能对海岸沉积物输运产生影响。
Breaking waves in the nearshore are known to generate a significant amount of high‐frequency (f > 5 Hz) energy. We investigate the correlation between the spectrum of seismic energy and the local sea states. We deployed a single three‐component broadband seismometer approximately 50 m from the seashore and recorded continuously for approximately 10 days. Our observations show that during elevated sea states, and presumably larger breaking waves in the surf zone, the power spectral density of the wave‐generated seismic energy shifts to lower frequencies and higher spectral amplitudes. This is similar to the observation that large plunging breakers generate 1–20 Hz acoustic infrasound, suggesting that a significant portion of the infrasound couples into seismic energy at the water/sea floor interface. Based on our observations and previous models, it appears that the seismic spectrum is sensitive to the wave size but not sediment movement. Regardless, the correlation of the seismic spectral power to the height and period of ocean waves suggests that seismic observations can be used as a proxy for local sea states, which may have implications for seashore sediment transport.