Development and Evaluations of the Broadband Ocean Bottom Seismometer (Yardbird-BB OBS) in Taiwan.

Abstract

Abstract This study focuses on the development and evaluation of the Broadband Ocean Bottom Seismometer (called Yardbird-BB OBS) in Taiwan. The Yardbird-BB OBS is a critical instrument used to recording seismic signals in deep-sea environments. Rigorous testing and evaluation methods are employed to ensure optimal performance and data recording capabilities. Components such as the data logger, seismic sensor leveling mechanism, acoustic device, and internal wiring undergo thorough performance evaluations prior to assembly. This guarantees the selection of high-performance components and verifies their functionality, preventing issues like data loss or incomplete recording. Once assembled, the Yardbird-BB OBS undergoes a deployment test in the deep sea, typically lasting 3–6 months, to record seismic signals from various sources worldwide. Recorded data from deployments in the Okinawa Trough in 2016 and 2017 are analyzed, highlighting significant seismic events such as a magnitude 7.8 earthquake in New Zealand and a magnitude 6.3 earthquake resulting from a nuclear test by North Korea. The OBS's performance is assessed through waveform analysis, specifically focusing on P-wave arrival times and waveform quality. The results showcase successful automatic leveling adjustment for the seismometer. These high-quality data recordings have valuable research applications, including the study of plate tectonics, estimation of crustal ages, determination of seafloor ambient noise, and improvement of earthquake location accuracy. Additionally, the study presents methods for verifying instrumental self-noise, dynamic range, digitization sensitivity, linearity error, clock drift, and power consumption of the data logger. Calibration procedures and evaluation methods provide valuable insights into the performance characteristics of the Yardbird-BB OBS. The comprehensive evaluations and testing methods outlined in this study contribute to a better understanding and enhancement of the Yardbird-BB OBS, enabling its effective deployment for long-term underwater data recording and valuable scientific research.