Infragravity waves in the deep ocean: Generation, propagation, and seismic hum excitation
نویسندگان
چکیده
منابع مشابه
Infragravity waves in the deep ocean: Generation, propagation, and seismic hum excitation
[1] Oceanic infragravity waves are investigated as a possible source of seismic free oscillations, often referred to as the ‘‘hum’’ of the Earth, using a numerical model of depth-independent, nondispersive, long-wave dynamics with a forcing from nonlinear interactions among the primary wind waves (including swell). Because of near-resonant amplification, the structure of the primary-wave forcin...
متن کاملThe Earth’s hum: the excitation of Earth normal modes by ocean waves
S U M M A R Y The recent discovery that the seismic normal modes of the Earth are excited to a nearly constant level during seismically quiet days (‘the hum of the Earth’) has lead to much speculation as to what drives the observed background in the absence of large earthquakes. Other authors have shown that the hum cannot be explained by the many small earthquakes occurring each day and have a...
متن کاملMicroseisms and hum from ocean surface gravity waves
[1] Ocean waves incident on coasts generate seismic surface waves in three frequency bands via three pathways: direct pressure on the seafloor (primary microseisms, PM), standing waves from interaction of incident and reflected waves (double-frequency microseisms, DF), and swell-transformed infragravity wave interactions (the Earth’s seismic hum). Beamforming of USArray seismic data shows that ...
متن کاملAmbient seismic wave field
The ambient seismic wave field, also known as ambient noise, is excited by oceanic gravity waves primarily. This can be categorized as seismic hum (1-20 mHz), primary microseisms (0.02-0.1 Hz), and secondary microseisms (0.1-1 Hz). Below 20 mHz, pressure fluctuations of ocean infragravity waves reach the abyssal floor. Topographic coupling between seismic waves and ocean infragravity waves at t...
متن کاملDominant source regions of the Earth’s ‘‘hum’’ are coastal
[1] Hum beam power observations using the USArray EarthScope transportable array, combined with infragravity wave observations, show that the dominant source area of the Earth’s hum over the 120–400 s period band during winter months is the Pacific coast of North America, with the western coast of Europe a secondary source region. Correlation of hum with model ocean wave heights indicates that ...
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ژورنال
عنوان ژورنال: Journal of Geophysical Research
سال: 2008
ISSN: 0148-0227
DOI: 10.1029/2007jc004562