Recent developments of ocean‐bottom pressure gauges (PG) have enabled us to observe various waves including seismic and tsunami waves covering periods of T ∼ 10⁰–10³ s. To investigate the quality for broadband observation, this study examined the broadband PG records (sampling rate of 1 Hz) around Japan associated with the 2010 Chile earthquake. We identified three distinct wave trains, attributed to seismic body waves, Rayleigh waves, and tsunamis. Clear dispersive features in the Rayleigh waves and tsunamis were explained by theories of elastic waves and gravity waves. Quantitative comparison between pressure change and nearby seismograms demonstrated the validity of the theoretical relation between pressure p and vertical acceleration a_z for ∼3 hr from the origin time. We also found a relationship between p and vertical velocity v_z holds only at the first P wave arrival, but not for later arrivals. Similar results were confirmed for various earthquakes with different source‐station distances and magnitudes, suggesting the robustness of these relations. The results demonstrate that the high‐sampling rate (≥1 Hz) is necessary to observe seismic‐wave dispersion and PG can record both seismic waves and tsunamis with reasonable quality for waveform analyses, whereas conventional onshore and offshore seismometers or tide gauges can observe either of seismic waves and tsunamis. Utilizing the high‐sampling PG in combination with the seismic and tsunami propagation theory for estimating earthquake source process or analyzing wave propagation processes in the ocean will deepen our geophysical understanding of the solid‐fluid coupled system in the Earth and contribute toward disaster mitigation.

中文翻译：

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高采样海底压力表覆盖时间从几秒到几小时的超宽带地震和海啸观测

的海底压力表（PG）的最新发展，使我们能够观察各种波包括地震和海啸波覆盖的周期Ť  〜10 ⁰ -10 ³ 秒。为了调查宽带观测的质量，本研究检查了与2010年智利地震有关的日本周围的宽带PG记录（采样率为1 Hz）。我们确定了三个不同的波列，分别归因于地震体波，瑞利波和海啸。弹性波和重力波的理论解释了瑞利波和海啸中明显的色散特征。压力变化与附近地震图之间的定量比较证明了压力p与压力之间理论关系的有效性。垂直加速度a _z从原点开始持续约3小时。我们还发现p和垂直速度v _z之间的关系仅在第一个P处成立波浪到达，但以后不来。对于不同震源站距离和震级的各种地震，也证实了类似的结果，表明了这些关系的稳健性。结果表明，高采样率（≥1 Hz）对于观察地震波散布是必不可少的，并且PG可以以合理的质量记录地震波和海啸以进行波形分析，而常规的陆上和海上地震仪或潮汐计可以观察到地震波和海啸。将高采样PG与地震和海啸传播理论相结合来估算地震震源过程或分析海洋中的波传播过程，将加深我们对地球固液耦合系统的地球物理理解，并有助于减轻灾害。