The Pacific OBS Research into Convecting Asthenosphere (ORCA) experiment
The Pacific OBS Research into Convecting Asthenosphere (ORCA) experiment
Seismological Research Letters (October 2021) 93 (1): 477-493
- arrays
- asthenosphere
- body waves
- broad-band spectra
- Cenozoic
- convection currents
- Cretaceous
- crust
- currents
- data bases
- data processing
- elastic waves
- Eocene
- marine methods
- Mesozoic
- multibeam methods
- ocean bottom seismographs
- P-waves
- Pacific Ocean
- Paleogene
- passive methods
- seismic waves
- seismographs
- Tertiary
- PacificArray
The Pacific ocean-bottom seismometer (OBS) Research into Convecting Asthenosphere (ORCA) experiment deployed two 30-station seismic arrays between 2018 and 2020-a US contribution to the international PacificArray project. The "Young ORCA" array deployed on approximately 40 Ma central Pacific seafloor had a approximately 68% data recovery rate, whereas the "Old ORCA" array deployed on approximately 120 Ma southwest Pacific seafloor had a approximately 80% recovery rate. We detail here the seismic data quality, spectral characteristics, and engineering challenges of this experiment. We provide information to assist users of this dataset, including OBS orientations and tables of daily data quality for all channels. Preliminary analysis illustrates the utility of these data for surface- and body-wave seismic imaging.
