Microearthquake activity in the West Philippine Basin and northern Ryukyu Trench region as observed by ocean bottom seismometers at the Amami Plateau

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.

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The GITEWS ocean bottom sensor packages

Natural Hazards and Earth System Science ◽

10.5194/nhess-10-1759-2010 ◽

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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An installation experiment with broadband ocean bottom seismometers for reducing low frequency seismic noises.

JAMSTEC Report of Research and Development ◽

10.5918/jamstecr.2009.131 ◽

2009 ◽

Vol 2009 ◽

pp. 131-139 ◽

Cited By ~ 2

Author(s):

Aki Ito ◽

Hiroko Sugioka ◽

Eiichiro Araki

Keyword(s):

Low Frequency ◽

Ocean Bottom ◽

Ocean Bottom Seismometers

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The pP phase generated in water covered areas

Bulletin of the Seismological Society of America ◽

10.1785/bssa0550040721 ◽

1965 ◽

Vol 55 (4) ◽

pp. 721-726

Author(s):

D. H. Shurbet

Keyword(s):

North America ◽

Crustal Structure ◽

West Coast ◽

Ocean Bottom ◽

The West ◽

Coefficient Of Reflection ◽

Uppermost Layer ◽

Epicenter Location

abstract The appearance of the pP phase, on seismograms, is strongly affected by the crustal structure in the vicinity of the epicenter. A recognizable pP phase is generated near the west coast of North America when the uppermost layer is water of sufficient depth. The generation of this pP is also affected by ocean bottom conditions. The bottom must probably be flat and the coefficient of reflection between the water and the bottom must be high. This pP phase may be useful in epicenter location and in crustal studies.

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Exploration in the Faeroe-Shetland Basin Using Densely Spaced Arrays of Ocean Bottom Seismometers

57th EAEG Meeting ◽

10.3997/2214-4609.201409219 ◽

1995 ◽

Author(s):

S. Hughes ◽

P. Barton ◽

D. Harrison ◽

M. Johnson

Keyword(s):

Ocean Bottom ◽

Ocean Bottom Seismometers

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Tidal Triggering of the Harmonic Noise in Ocean-Bottom Seismometers

Seismological Research Letters ◽

10.1785/0220190080 ◽

2020 ◽

Vol 91 (2A) ◽

pp. 803-813 ◽

Cited By ~ 1

Author(s):

Telluri Ramakrushana Reddy ◽

Pawan Dewangan ◽

Lalit Arya ◽

Pabitra Singha ◽

Kattoju Achuta Kamesh Raju

Keyword(s):

Spectral Analysis ◽

Fundamental Frequency ◽

Ocean Bottom ◽

Automated Algorithm ◽

Tidal Triggering ◽

Spectral Peaks ◽

Ocean Bottom Seismometers ◽

Oceanic Tides ◽

Harmonic Noise

Abstract We observed a harmonic noise (HN) in DEutscher Geräte-Pool für Amphibische Seismologie ocean-bottom seismometers (OBSs) data recorded from the Andaman–Nicobar region. The HN is characterized by sharp spectral peaks with a fundamental frequency and several overtones occurring at integer multiples of the fundamental frequency. We used an automated algorithm to quantify the occurrence of HN for the entire four-month deployment period (1 January 2014 to 30 April 2014). The algorithm detected more than 23 days of HN for some OBS stations. The spectral analysis of the hourly count of HN shows distinct lunar and solar tidal periodicities at 4.14, 6.1, 6.22, 12, and 12.4 hr as well as 13.66 days. The observed periodicities provide evidence of tidal triggering of HN. The HN is generated by the strumming of head buoys due to seafloor currents initiated by oceanic tides in the Andaman–Nicobar region.

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