Ranging to fin whale calls at full ocean depths using single ocean bottom seismometers

2021 ◽  
Vol 150 (4) ◽  
pp. A83-A83
Author(s):  
Rose Hilmo ◽  
William S. Wilcock
Keyword(s):  
Ocean Bottom ◽  
Fin Whale ◽  
Ocean Bottom Seismometers

scholarly journals Source Levels of 20 Hz Fin Whale Notes Measured as Sound Pressure and Particle Velocity from Ocean-Bottom Seismometers in the North Atlantic

2021 ◽  
Vol 9 (6) ◽  
pp. 646
Author(s):  
Andreia Pereira ◽  
Miriam Romagosa ◽  
Carlos Corela ◽  
Mónica A. Silva ◽  
Luis Matias
Keyword(s):  
Sample Size ◽  
Particle Velocity ◽  
North Atlantic ◽  
Ocean Bottom ◽  
Geographical Differences ◽  
Fin Whale ◽  
The North ◽  
Ocean Bottom Seismometers ◽  
Source Level ◽  
The North Atlantic

Source level is one factor that determines the effectiveness of animal signal transmissions and their acoustic communication active space. Ocean-bottom seismometers (OBS) are platforms of opportunity to monitor marine species because they record data as pressure fluctuations in the water using a hydrophone and/or as particle velocity of the seabed using a seismometer. This study estimates source levels of 20 Hz fin whale notes recorded simultaneously in these two OBS channels and in two areas of the North Atlantic (Azores and southwest Portugal). It also discusses factors contributing to the variability of the estimates, namely geographical (deployment areas), instrumental (recording channels and sample size), and temporal factors (month of detected notes, inter-note interval, and diving duration). The average source level was 196.9 dB re 1 µPa m for the seismometer (derived from particle velocity measurements) and 186.7 dB re 1 µPa m for the hydrophone. Variability was associated with sample size, instrumental characteristics, acoustic propagation, and month of recordings. Source level estimates were very consistent throughout sequences, and there was no indication of geographical differences. Understanding what causes variation in animal sound source levels provides insights into the function of sounds and helps to assess the potential effects of increasing anthropogenic noise.

Seismic crustal imaging using fin whale songs

Science ◽  
2021 ◽  
Vol 371 (6530) ◽  
pp. 731-735
Author(s):  
Václav M. Kuna ◽  
John L. Nábělek
Keyword(s):  
Lower Crust ◽  
Seismic Velocity ◽  
Ocean Bottom ◽  
Fin Whale ◽  
Northeast Pacific ◽  
Air Gun ◽  
Ocean Bottom Seismometers ◽  
Animal Vocalizations ◽  
Oceanic Sediment ◽  
Northeast Pacific Ocean

Fin whale calls are among the strongest animal vocalizations that are detectable over great distances in the oceans. We analyze fin whale songs recorded at ocean-bottom seismometers in the northeast Pacific Ocean and show that in addition to the waterborne signal, the song recordings also contain signals reflected and refracted from crustal interfaces beneath the stations. With these data, we constrain the thickness and seismic velocity of the oceanic sediment and basaltic basement and the P-wave velocity of the gabbroic lower crust beneath and around the ocean bottom seismic stations. The abundant and globally available fin whale calls may be used to complement seismic studies in situations where conventional air-gun surveys are not available.

scholarly journals Microearthquake seismicity and focal mechanisms at the Rodriguez Triple Junction in the Indian Ocean using ocean bottom seismometers

2001 ◽  
Vol 106 (B12) ◽  
pp. 30689-30699 ◽  
Author(s):  
Kei Katsumata ◽  
Toshinori Sato ◽  
Junzo Kasahara ◽  
Naoshi Hirata ◽  
Ryota Hino ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Triple Junction ◽  
Focal Mechanisms ◽  
Ocean Bottom ◽  
Ocean Bottom Seismometers ◽  
The Indian Ocean

Comparison of the S/N ratios of low-frequency hydrophones and geophones as a function of ocean depth

1981 ◽  
Vol 71 (5) ◽  
pp. 1649-1659
Author(s):  
Thomas M. Brocher ◽  
Brian T. Iwatake ◽  
Joseph F. Gettrust ◽  
George H. Sutton ◽  
L. Neil Frazer
Keyword(s):  
Nova Scotia ◽  
Continental Margin ◽  
Low Frequency ◽  
Weather Conditions ◽  
Ocean Bottom ◽  
Ocean Bottom Seismometer ◽  
Scotian Shelf ◽  
Ocean Bottom Seismometers ◽  
Particle Velocities ◽  
Refraction Data

abstract The pressures and particle velocities of sediment-borne signals were recorded over a 9-day period by an array of telemetered ocean-bottom seismometers positioned on the continental margin off Nova Scotia. The telemetered ocean-bottom seismometer packages, which appear to have been very well coupled to the sediments, contained three orthogonal geophones and a hydrophone. The bandwidth of all sensors was 1 to 30 Hz. Analysis of the refraction data shows that the vertical geophones have the best S/N ratio for the sediment-borne signals at all recording depths (67, 140, and 1301 m) and nearly all ranges. The S/N ratio increases with increasing sensor depth for equivalent weather conditions. Stoneley and Love waves detected on the Scotian shelf (67-m depth) are efficient modes for the propagation of noise.

scholarly journals The GITEWS ocean bottom sensor packages

2010 ◽  
Vol 10 (8) ◽  
pp. 1759-1780
Author(s):  
O. Boebel ◽  
M. Busack ◽  
E. R. Flueh ◽  
V. Gouretski ◽  
H. Rohr ◽  
...  
Keyword(s):  
Warning System ◽  
Deep Ocean ◽  
Indian Ocean Tsunami ◽  
False Alarms ◽  
Ocean Bottom ◽  
Bottom Pressure ◽  
Tsunami Early Warning ◽  
Ocean Bottom Seismometers ◽  
First Results ◽  
Sensor Package

Abstract. The German-Indonesian Tsunami Early Warning System (GITEWS) aims at reducing the risks posed by events such as the 26 December 2004 Indian Ocean tsunami. To minimize the lead time for tsunami alerts, to avoid false alarms, and to accurately predict tsunami wave heights, real-time observations of ocean bottom pressure from the deep ocean are required. As part of the GITEWS infrastructure, the parallel development of two ocean bottom sensor packages, PACT (Pressure based Acoustically Coupled Tsunameter) and OBU (Ocean Bottom Unit), was initiated. The sensor package requirements included bidirectional acoustic links between the bottom sensor packages and the hosting surface buoys, which are moored nearby. Furthermore, compatibility between these sensor systems and the overall GITEWS data-flow structure and command hierarchy was mandatory. While PACT aims at providing highly reliable, long term bottom pressure data only, OBU is based on ocean bottom seismometers to concurrently record sea-floor motion, necessitating highest data rates. This paper presents the technical design of PACT, OBU and the HydroAcoustic Modem (HAM.node) which is used by both systems, along with first results from instrument deployments off Indonesia.

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