Journal
GEOPHYSICAL JOURNAL INTERNATIONAL
Volume 212, Issue 2, Pages 891-899Publisher
OXFORD UNIV PRESS
DOI: 10.1093/gji/ggx449
Keywords
Time-series analysis; Interface waves; Seismic instruments; Seismic noise
Categories
Funding
- National Natural Science Foundation of China [41676033, 91128209]
- National Program on Global Changing and Air-Sea Interaction [GASI-GEOGE-05]
- Shenzhen Sci. and Tech. Innovation Commission [2017-131, 2017-173]
- SUSTech
Ask authors/readers for more resources
One of long-standing problems in underwater seismic studies is the inaccurate timing due to the fact the internal clock of Ocean Bottom Seismograph (OBS) is unable to synchronize with GPS. Here we present correcting large OBS clock errors and temporal drifts in a passive-source OBS array experiment in South China Sea by cross-correlating hydrophone recordings of OBS pairs. We show that, in this experiment, the noise cross-correlation function (NCCF) from hydrophone signals can retrieve higher signal-to-noise ratio (SNR) Scholte waves than the NCCF from seismometer. Because the hydrophone is positioned in the water above the seafloor, their NCCFs are thus less contaminated by more complicated solid-mode phases at the sediment-covered seafloor, leading to higher SNR for hydrophone's NCCFs. The relatively high SNR of Scholte waves enables us to use the daily NCCF (or stacked NCCFs of a few days) to constrain the temporal variations of the clock errors. A two-step approach is employed in this study to tackle large OBS clock errors: using predicted traveltimes of P phases from earthquakes to roughly correct the time, and then using the time asymmetry of two Scholte waves on NCCF to fine-tune the clock drifts. The uncertainty analysis indicates that the average error of our corrections is less than 0.2 s, suggesting the clock-corrected OBS data are valuable for seismic studies using surface waves and S waves.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available