Marine Geoscience Data System
JdF:Axial_Bohnenstiehl Hydroacoustic, Seismic:Passive:OBH, Seismic:Passive:OBS
Catalog of impulsive acoustic events identified for the April-May 2015 eruption of Axial Seamount
Impulsive acoustic events were identified on station AXEC2 by matching waveforms against a suite of 817 waveform templates chosen from isolated arrivals, with high signal-to-noise, that span the eruptive period. Template matching using three-component (HDH, HHZ, and HHN) waveforms returned a set of >37,000 detections (correlation coefficient >0.7). For each detection on AXEC2, the vertical (HHZ) channel waveform was cross-correlated against the other six OOI stations within the caldera to precisely determine the time of the first (sea surface-reflected) and second (sea surface- and seafloor-reflected) arriving phases across the network. Locations were determined using a grid search with a 25 x 25 m spatial resolution. Travel times for both phases were computed assuming a planar sloping seafloor between the source and each receiver with a constant sound velocity of 1485 m/s. The final catalog contains locations for ~22,000 impulsive sounds constrained using at least 7 arriving phases, with an average root mean square error of 0.022 sec. The mean location uncertainty is ~140 m (chi-squared – misfit at 68% confidence). The peak amplitude of each arrival was measured and corrected for geometric spreading loss to estimate the source level (units of dB are 1 micro-Pa @ 1 m). There are additional range-dependent location biases related to anomalies in the water column velocity structure and unmodeled bathymetric effects, which influence the travel times of the sea surface- and seafloor-bouncing arrivals recorded in the caldera. See Le Saout et al. (2020 G-Cubed) for discussion. The data file is in comma-separated ASCII text format and contains the latitude, longitude, acoustic source level, and origin time (year, month, day, hour, minute, second) for acoustic events associated with lava extrusion during the April-May 2015 eruption of Axial Seamount. The data file was generated as part of a project called Research: Earthquake Catalog and Waveform Analysis to Assess the Evolution of Axial Seamount Surrounding the 2015 Eruption. Funding was provided by NSF grant OCE16-35276.
Device Info
Seismic:OBS
Device Info
Seismic:OBH
Platform
Axial Node: OOI Cabled Array (Array)
NSF
Awards
Quality
2
The data have been processed/modified to a level beyond that of basic quality control (e.g. final processed sonar data, photo-mosaics).

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