Source locations of secondary microseisms in western Europe: Evidence for both coastal and pelagic sources

Chevrot, Sébastien; Sylvander, Matthieu; Benahmed, Sébastien; Ponsolles, Christian; Lefèvre, Jean‐Michel; Paradis, Daniel

doi:10.1029/2007jb005059

Cited by 93 publications

(91 citation statements)

References 30 publications

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“…The spatial origin of this peak seems to be due to both coastal and deep-ocean sources [Cessaro, 1994;Chevrot et al, 2007], and the amplitude of the signal can be correlated with sources of different origin such as bathymetry, ocean wave height, wind, storms, and hurricanes [e.g., Kedar et al, 2008]. Regardless of the origin, the final effects are pressure pulses at sea, which propagate to the sea floor and then generate microseismicity.…”

Section: High-frequency Gravity Signal Of 6 To 11 October 2011mentioning

confidence: 99%

Volcanic signatures in time gravity variations during the volcanic unrest on El Hierro (Canary Islands)

et al. 2014

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Gravity changes occurring during the initial stage of the 2011-2012 El Hierro submarine eruption are interpreted in terms of the preeruptive signatures during the episode of unrest. Continuous gravity measurements were made at two sites on the island using the relative spring gravimeter LaCoste and Romberg gPhone-054. On 15 September 2011, an observed gravity decrease of 45 μGal, associated with the southward migration of seismic epicenters, is consistent with a lateral magma migration that occurred beneath the volcanic edifice, an apparently clear precursor of the eruption that took place 25 days later on 10 October 2011. High-frequency gravity signals also appeared on 6-11 October 2011, pointing to an occurring interaction between a magmatic intrusion and the ocean floor. These important gravity changes, with amplitudes varying from 10 to À90 μGal, during the first 3 days following the onset of the eruption are consistent with the northward migration of the eruptive focus along an active eruptive fissure. An apparent correlation of gravity variations with body tide vertical strain was also noted, which could indicate that concurrent tidal triggering occurred during the initial stage of the eruption.

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Section: High-frequency Gravity Signal Of 6 To 11 October 2011mentioning

confidence: 99%

Volcanic signatures in time gravity variations during the volcanic unrest on El Hierro (Canary Islands)

et al. 2014

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“…[4] Results from beamforming of microseismic data using seismic arrays have been reported elsewhere [e.g., Haubrich and McCamy, 1969;Chevrot et al, 2007;Gerstoft et al, 2008], but not in New Zealand. Here we employ frequencydomain beamforming of vertical-component data from a seismograph array located in the Taranaki region, western North Island (see Figure 1), to determine the locations of microseism generation.…”

Section: Introductionmentioning

confidence: 99%

Fundamental and higher‐mode Rayleigh wave characteristics of ambient seismic noise in New Zealand

Brooks

Townend

Gerstoft

et al. 2009

Geophysical Research Letters

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In order to use ambient seismic noise for mapping Earth's structure, it is important to understand the spatio‐temporal characteristics of the noise field. This study uses data collected during four austral winter months of 2002 to investigate New Zealand's ambient seismic noise field in the double‐ocean‐wave‐frequency range (0.1–0.3 Hz). It is shown via beamforming analysis that there are two distinct dispersive waves in the data. These waves can be separated. Their estimated phase velocities (2.5–2 and 4–3 km/s in the frequency range 0.14–0.25 Hz) match well with fundamental and higher‐mode Rayleigh dispersion curves. Studies of double‐wave‐frequency microseisms elsewhere generally show the Rayleigh noise fields to be dominated by fundamental mode waves. The reason why higher‐mode signals are observed here may reflect a combination of long ocean wave periods, large waveheights, the direct deep water approach to narrow continental margins, and the proximity of the seismograph array to the source regions.

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“…Some studies propose that ground motions are induced in shallow water regions like continental shelves (Friedrich et al 1998;Bromirski et al 1999;Bromirski and Duennebier 2002;Bromirski 2001;Essen et al 2003;Rhie and Romanowicz 2006;Kedar and Webb 2005; Bromirski and Gerstoft 2009). Other scientists propose that the source region is under or trailing a typhoon (Cessaro 1994;Stehly et al 2006;Chevrot et al 2007;Kedar et al 2008;Gerstoft et al 2008;Koper and de Foy 2008;Landes et al 2010;Chi et al 2010). Some of the controversy might be due to different types of microseisms used in the studies (e.g.…”

Section: Introductionmentioning

confidence: 99%

Seismic monitoring of western Pacific typhoons

et al. 2010

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Typhoons inflict large damage to societies, but are usually difficult to monitor in close proximity in realtime without expensive instruments. Here we study the possibility of using seismic waveforms on the seafloor and on land to monitor the turning of a far away or approaching typhoon. Up to 67% of the typhoons making landfall in Taiwan come from the eastern shore, so that we deployed broadband ocean-bottom seismometers (OBSs) offshore eastern Taiwan in 2006 to study ground motion in close proximity to a typhoon. Typhoons generate ocean waves, which generate pressure signals in the water column before being transmitted to the seafloor as seismic waves and recorded by the OBSs. The ground motions on the seafloor correlate with locally increased (ocean) wave heights and wave periods, suggesting that the ground motions are mostly induced by in situ or nearby pressure fields, as shown by coherence function analyses. When a typhoon turns and changes wave-wave interaction near the source region, a new set of en echelon patterns develops which can be observed by OBSs and land stations. Similar features occur when a typhoon crosses a landmass and re-enters the ocean. The energy level ratio between the single-frequency and double-frequency microseisms also changes abruptly when the typhoon turns. These features can potentially help near real-time early warning with little cost to complement other conventional typhoon early warning methods.

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Source locations of secondary microseisms in western Europe: Evidence for both coastal and pelagic sources

Cited by 93 publications

References 30 publications

Volcanic signatures in time gravity variations during the volcanic unrest on El Hierro (Canary Islands)

Volcanic signatures in time gravity variations during the volcanic unrest on El Hierro (Canary Islands)

Fundamental and higher‐mode Rayleigh wave characteristics of ambient seismic noise in New Zealand

Seismic monitoring of western Pacific typhoons

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