T‐phase and tsunami pressure waveforms recorded by near‐source IMS water‐column hydrophone triplets during the 2015 Chile earthquake

Matsumoto, Hiroyuki; Haralabus, Georgios; Zampolli, Mario; Özel, Nurcan Meral

doi:10.1002/2016gl071425

Cited by 11 publications

(16 citation statements)

References 26 publications

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“…( b ) Power spectral densities (PSDs) comparing the DAS measurement and the co-located hydrophone. Note that the PSD of the hydrophone corrected with the sensor’s response (gray line) is synthesized by extrapolation of a low frequency range down to using the same modeling procedure 43 . ( c ) DAS recording of the entire Muroto cable during a regional earthquake with magnitude of 1.7.…”

Section: Resultsmentioning

confidence: 99%

“…We examined the data obtained by the co-located hydrophone of OBS51. The PSDs of the hydrophone are also shown in Fig 4 b, in which the sensor response is corrected by extrapolation of frequency range down to 43 . It shows that the hydrophone observes the ocean microseismic background noise (ocean microseisms) in the low frequency range below 1 Hz, as typically manifested in the deep ocean 40 .…”

Section: Resultsmentioning

confidence: 99%

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Detection of hydroacoustic signals on a fiber-optic submarine cable

Matsumoto

Araki

Kojima

et al. 2021

Sci Rep

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A ship-based seismic survey was conducted close to a fiber-optic submarine cable, and 50 km-long distributed acoustic sensing (DAS) recordings with air-gun shots were obtained for the first time. We examine the acquired DAS dataset together with the co-located hydrophones to investigate the detection capability of underwater acoustic (hydroacoustic) signals. Here, we show the hydroacoustic signals identified by the DAS measurement characterizing in frequency-time space. The DAS measurement can be sensitive for hydroacoustic signals in a frequency range from $$10^{-1}\,\text {Hz}$$ 10 - 1 Hz to a few tens of Hz which is similar to the hydrophones. The observed phases of hydroacoustic signals are coherent within a few kilometers along the submarine cable, suggesting the DAS is suitable for applying correlation analysis using hydroacoustic signals. Although our study suggests that virtual sensor’s self-noise of the present DAS measurement is relatively high compared to the conventional in-situ hydroacoustic sensors above a few Hz, the DAS identifies the ocean microseismic background noise along the entire submarine cable except for some cable sections de-coupled from the seafloor.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Detection of hydroacoustic signals on a fiber-optic submarine cable

Matsumoto

Araki

Kojima

et al. 2021

Sci Rep

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“…Long‐range propagation of low‐frequency underwater sound phases is a key feature of the hydroacoustic waveform component of the International Monitoring System (IMS). As part of the verification regime for the Comprehensive Nuclear‐Test‐Ban Treaty (CTBT) of 1996, the objective of the IMS hydrophone network is to globally detect underwater nuclear explosions, but the comprehensive installation also enables the study of natural phenomena, including among others, earthquake rupture propagation (Guilbert et al, ; Tolstoy & Bohnenstiehl, ), tsunami signals (Matsumoto et al, ), ocean acoustic propagation (Evers & Snellen, ), and marine mammal vocalization (Le Bras et al, ; Ward et al, ). A total of 11 hydroacoustic receiver sites are in operation worldwide, six of which are hydrophone triplet arrays, typically deployed at remote ocean islands and near the SOFAR channel axis.…”

Section: Introductionmentioning

confidence: 99%

Tracking Submarine Volcanic Activity at Monowai: Constraints From Long‐Range Hydroacoustic Measurements

et al. 2018

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Monowai is a submarine volcanic center in the Kermadec Arc, Southwest Pacific Ocean. In the past, activity at the volcano had been intermittently observed in the form of fallout at the sea surface, discolored water, changes in seafloor topography, and T phase seismicity, but there is no continuous record for more recent years. In this study, we investigated 3.5 years of recordings at a hydrophone array of the International Monitoring System, located near Juan Fernández Islands, for long‐range underwater sound waves from Monowai. Results from direction‐of‐arrival calculations and density‐based spatial clustering indicate that 82 discrete episodes of activity occurred between July 2003 and March 2004 and from April 2014 to January 2017. Volcanic episodes are typically spaced days to weeks apart, range from hours to days in length, and amount to a cumulative sum of 137 days of arrivals in total, making Monowai one of the most active submarine arc volcanoes on Earth. The resolution of the hydrophone recordings surpasses broadband network data by at least 1 order of magnitude, identifying seismic events as low as 2.2 mb in the Kermadec Arc region. Further observations suggest volcanic activity at a location approximately 400 km north of Monowai in the Tonga Arc and at Healy or Brothers volcano in the southern Kermadec Arc. Our findings are consistent with previous studies and highlight the exceptional capabilities of the International Monitoring System network for the scientific study of active volcanism in the global ocean.

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“…Six hydrophone stations, typically configured as triplet receiver arrays and moored in the deep sound channel, are in operation worldwide to detect nuclear explosions in the global ocean. However, IMS hydrophone data have implications beyond the realm of test‐ban monitoring, for example, when studying tsunami signals (Matsumoto et al, 2016), and sources of low‐frequency ocean noise (Woolfe & Sabra, 2015). Here we focus on recordings of IMS station H11 at Wake Island, where hydroacoustic arrivals associated with the 2014 eruption at Ahyi were recorded across the northwestern Pacific basin and over a geodesic distance of 2,283 km.…”

Section: Introductionmentioning

confidence: 99%

Hydroacoustic Measurements of the 2014 Eruption at Ahyi Volcano, 20.4°N Mariana Arc

Metz

Grevemeyer

2018

Geophysical Research Letters

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Ahyi is a fully submerged arc volcano in the Northern Mariana Islands, northwestern Pacific Ocean. In April and May 2014, the volcano erupted over a period of 15 days. Results from direction-of-arrival calculations show that underwater sound phases associated with the episode were recorded as far as Wake Island, where a hydrophone triplet array is operated as part of the International Monitoring System. After a 3.5-hr-long sequence of hydroacoustic precursory events, explosive volcanic activity occurred in two distinct, several-days-long bursts, accompanied by a notable decrease in low-frequency arrivals that may indicate a shift in signal source parameters. Acoustic resolution of the hydrophone data supersedes broadband networks by almost 1 order of magnitude, successfully identifying seismic events at Ahyi as low as 2.5 m b . Total radiated acoustic energy of the eruption is estimated at 9.7 10 13 J, which suggests that submarine volcanic activity contributed significantly to the ocean soundscape.Plain Language Summary Little is known about active volcanism in the global ocean due to the inherent inaccessibility of the marine environment for conventional monitoring techniques. Here we resort to long-range hydroacoustic measurements to study the 2014 eruption of Ahyi, an active submarine volcano located in the Mariana Arc, northwestern Pacific Ocean. We show that underwater sound phases associated with the 2014 eruption of the volcano were recorded by hydrophones of the International Monitoring System, a global sensor network maintained by the Comprehensive Nuclear-Test-Ban Treaty Organization. Hydroacoustic data suggest that several precursory events preceded the 2-week-long, main eruptive episode, potentially indicating the collapse of the magma chamber and the subsequent intrusion of material into the volcanic conduit. We observe a relative decrease in lower-frequency arrivals toward the end of the eruption, which we attribute to changes in signal source parameters inside the edifice. The resolution of the International Monitoring System hydrophones supersedes broadband data recorded at land-based seismometers in the region, detecting seismic activity at Ahyi as low as 2.5 m b . In a final step, we estimate the substantial acoustic energy release of the eruption and conclude that natural sources of underwater sound should be taken into account when studying the ocean soundscape.

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T‐phase and tsunami pressure waveforms recorded by near‐source IMS water‐column hydrophone triplets during the 2015 Chile earthquake

Cited by 11 publications

References 26 publications

Detection of hydroacoustic signals on a fiber-optic submarine cable

Detection of hydroacoustic signals on a fiber-optic submarine cable

Tracking Submarine Volcanic Activity at Monowai: Constraints From Long‐Range Hydroacoustic Measurements

Hydroacoustic Measurements of the 2014 Eruption at Ahyi Volcano, 20.4°N Mariana Arc

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