Global trends in extremal microseism intensity

Aster, R. C.; McNamara, Daniel E.; Bromirski, Peter D.

doi:10.1029/2010gl043472

Cited by 57 publications

(58 citation statements)

References 25 publications

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“…So the jumping of the en enchelon pattern and the abrupt changes of that ratio can be used to monitor the turning of a typhoon in near real time. Aster et al (2008Aster et al ( , 2010 and Bromirski and Kossin (2008) have demonstrated that it is possible to use available seismograms to study historic trends of extreme tropical cyclones and their implication in terms of global warming. Lessons learned from this study can also be applied to seismic waveforms recorded before the satellite era to study decadal-scale climate changes.…”

Section: Discussionmentioning

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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Section: Discussionmentioning

confidence: 99%

Seismic monitoring of western Pacific typhoons

et al. 2010

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“…Therefore, it is now possible to perform longitudinal studies of station performance in order to identify degradation or mis-installation of seismic equipment (e.g., www.ldeo.columbia.edu/ ~ekstrom/Projects/WQC.html). Long-term noise analysis also provides insight into the evolution of the ocean wave climate, specifically whether the frequency and intensity of storms have changed as global temperatures have changed (Bromirski et al, 1999;Grevemeyer et al, 2000;Aster et al, 2008Aster et al, , 2010Koper et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Frequency dependent polarization analysis of ambient seismic noise recorded at a broadband seismometer in the central United States

Koper

Hawley

2010

Earthq Sci

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We present a new approach to polarization analysis of seismic noise recorded by three-component seismometers. It is based on statistical analysis of frequency-dependent particle motion properties determined from a large number of time windows via eigenanalysis of the 3-by-3, Hermitian, spectral covariance matrix. We applied the algorithm to continuous data recorded in 2009 by the seismic station SLM, located in central North America. A rich variety of noise sources was observed. At low frequencies (<0.05 Hz) we observed a tilt-related signal that showed some elliptical motion in the horizontal plane. In the microseism band of 0.05−0.25 Hz, we observed Rayleigh energy arriving from the northeast, but with three distinct peaks instead of the classic single and double frequency peaks. At intermediate frequencies of 0.5−2.0 Hz, the noise was dominated by non-fundamental-mode Rayleigh energy, most likely P and Lg waves. At the highest frequencies (>3 Hz), Rayleigh-type energy was again dominant in the form of Rg waves created by nearby cultural activities. Analysis of the time dependence of noise power shows that a frequency range of at least 0.02−1.0 Hz (much larger than the microseism band) is sensitive to annual, meteorologically induced sources of noise.

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“…These advantages explain the recent keen interest in exploiting seismic noise to illuminate the elastic structure of the earth [ Shapiro and Campillo , ; Shapiro et al ., ; Sabra et al , ] and its transient variations attributable to volcanic and seismic activity [ Brenguier et al ., , ; Durand et al ., ; Rivet et al ., ]. Taking advantage of the link between sea states and microseisms, noise records are also analyzed to detect seasonal or long‐term variations, interpreted in turn as changes in climate [ Bromirski et al ., ; Grevemeyer et al ., ; Aster et al ., , ; Stutzmann et al . , ; Ebeling and Stein , ; Ardhuin et al ., ; Traer et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Detection of microseismic compressional (P) body waves aided by numerical modeling of oceanic noise sources

et al. 2013

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[1] Among the different types of waves embedded in seismic noise, body waves present appealing properties but are still challenging to extract. Here we first validate recent improvements in numerical modeling of microseismic compressional (P) body waves and then show how this tool allows fast detection and location of their sources. We compute sources at~0.2 Hz within typical P teleseismic distances (30-90°) from the Southern California Seismic Network and analyze the most significant discrete sources. The locations and relative strengths of the computed sources are validated by the good agreement with beam-forming analysis. These 54 noise sources exhibit a highly heterogeneous distribution, and cluster along the usual storm tracks in the Pacific and Atlantic oceans. They are mostly induced in the open ocean, at or near water depths of 2800 and 5600 km, most likely within storms or where ocean waves propagating as swell meet another swell or wind sea. We then emphasize two particularly strong storms to describe how they generate noise sources in their wake. We also use these two specific noise bursts to illustrate the differences between microseismic body and surface waves in terms of source distribution and resulting recordable ground motion. The different patterns between body and surface waves result from distinctive amplification of ocean wave-induced pressure perturbation and different seismic attenuation. Our study demonstrates the potential of numerical modeling to provide fast and accurate constraints on where and when to expect microseismic body waves, with implications for seismic imaging and climate studies.Citation: Obrebski, M., F. Ardhuin, E. Stutzmann, and M. Schimmel (2013), Detection of microseismic compressional (P) body waves aided by numerical modeling of oceanic noise sources,

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Global trends in extremal microseism intensity

Cited by 57 publications

References 25 publications

Seismic monitoring of western Pacific typhoons

Seismic monitoring of western Pacific typhoons

Frequency dependent polarization analysis of ambient seismic noise recorded at a broadband seismometer in the central United States

Detection of microseismic compressional (P) body waves aided by numerical modeling of oceanic noise sources

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