Ocean Bottom Seismometer (OBS): An instrument for marine seismic data acquisition

The OBS (Ocean Bottom Seismoemter) has been a key instrument for geophysical study of sea sub-bottom layers in the last decades. Now scientists are demanding highly relaible autonomous equipment capable of staying underwater for long periods of time and therefore handling large data storage. Power consumption of the acquisition system as well as a stable time base with temperature are the main issues in order to achieve high autonomy together with a good data quality. This paper presents a new Ocean Bottom Seismometer designed to be used in marine mid-term surveys. To achieve our goals, a new low power datalogger with high resolution and Signal-to-Noise Ratio (SNR) based on Compactflash memory card is designed to enable continues data acquisition. The equipment has been evaluated in real environmental conditions during a test cruise in 2006.