Low power and easy to use ocean bottom seismometer (OBS) for long period surveys

The OBS (ocean bottom seismometer) has been a key instrument for geophysical study of sea subbottom layers in the last decades. Now scientists are demanding highly reliable 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 OBS designed to be used in marine long term surveys. To achieve our goals, a new datalogger based on Compactflash memories with high data transfer capacity is designed to enable continuous data acquisition. The equipment is now under evaluation where lab tests have been carried out and tests under real environmental conditions are programmed for second semester of 2005.