Seismic Experiment Studying the Origin of Auckland Volcanic Field: Phase I Seafloor Data Set

Abstract This article describes an ocean-bottom seismic data set collected offshore New Zealand’s North Island as part of a multinational amphibious experiment investigating the Auckland volcanic field. From August 2023 to September 2024, 20 broadband ocean-bottom seismographs were deployed at water depths of 1200–2700 m, yielding approximately one year of continuous recordings from 15 successfully recovered instruments. We present comprehensive quality metrics including instrument orientations (determined via Rayleigh-wave polarization with uncertainties < 7.5°), tilt characteristics (predominantly < 2.5°), and clock drift corrections (achieved to 0.1 s precision using ambient noise cross correlation for five units lacking Global Positioning System synchronization). The data set exhibits excellent signal fidelity in the microseismic band (2–20 s), with vertical components showing substantially lower noise than horizontal components. Notably, two instruments (R12 and R42) had a delayed recovery, and recorded 16–18 months of continuous data. All data will be publicly archived at the U.S. National Geophysical Facility Data Repository following a three-year proprietary period, providing critical offshore coverage to complement New Zealand’s land-based seismic network for studies of intraplate volcanism and subduction zone dynamics.