Broad-band BOS (BBYB) development and calibration in Taiwan

Since 2009, combine with Academia Sinica, National Applied Research Laboratories and National Sun Yat-sen University formed ocean bottom seismograph (OBS) development team to develop sub-broadband OBS (called Yardbird OBS). Through a series deploy experiment at seafloor offshore Taiwan that got a lot of data can be used to study plate tectonics, seismic activity, source characteristics. Nowadays they have pretty good results already. Due to bandwidth limitations of the Yardbird OBS that inadequate to use for analyze global-scale earthquake. Therefor developing broadband ocean bottom seismograph is an important goal for the development team. Currently the broadband OBS (called BBYB) design and construction have completed the initial experiment phase. Due to underwater instruments always got high risk. Something accidentally making equipment sank in the sea cannot be recovery. Even recovery of equipment may also be causing poor performance because there is no data record. It cannot be to accomplish the experiment mission. In order to improve the OBS performance, avoid OBS dis-recovery or data collection is incomplete, must be sure all OBS's each component (such as seismic data recording device, balanced body, sonar dashboard, instruments and internal wiring ...) with well-done quality before assembly. Each component could go through very rigorous testing, strict and pick out the good components in the assembly process. Be sure all of produce the OBS under the water after a long deployment could successful recovery and got valuable data. In this presentation we will show a serial testing procedure and results for quality each BBYB component. Such as: Data logger: digitizer sensitivity, sampling rate, clock timing. Acoustic controller: function of Enable, Disable, Range, Release 1, Release 2, Option 1(Release disable). Air pressure gauge for glass ball: accuracy. A check lists of connector wiring check for assembling instrument. Design deploy and recovery procedure for operation on deck. We hope through repeated testing to ensure perfect performance of BBYB and apply the testing concept to another equipment for improve instruments performance. Keywords: ocean bottom seismograph (OBS); Data logger; Acoustic controller; Air pressure gauge.