The ambient noise characteristics in the ocean bottom environment offshore Taiwan

The data recorded at broad-band ocean bottom seismograph (OBS) often contains significant noise sources that are not present in land-based seismic records mainly due to the phenomenon happens in the water column. The peaks of primary and secondary microseisms in the spectrum reveal different patterns in different regions. Its essential to understand of seismic noise of the data recording in any OBS experiment and eventually remove the significant noise signals from the raw OBS data. We applied spectrum analysis using probability density functions to characterize the background noise signals for 3-components ground motion data and pressure recoding at different water depth at different tectonic regions from several passive broad-band OBS experiments offshore Taiwan including TAIGER project. The temporal and spatial variations results from different types of the ocean waves. In addition, we compared the noise spectrum recored at stations in NoMelt project which located at the center of Pacific. The double-frequency microseismic waves appear stronger in NoMelt stations. Thought out the analysis, we show the site characterization for OBSs offshore Taiwan to understand the local geological setting .