dc.contributor |
Háskóli Íslands |
dc.contributor |
University of Iceland |
dc.contributor.author |
Wilcock, William S. D. |
dc.contributor.author |
Webb, Spahr C. |
dc.contributor.author |
Bjarnason, Ingi Þorleifur |
dc.date.accessioned |
2018-02-14T11:32:03Z |
dc.date.available |
2018-02-14T11:32:03Z |
dc.date.issued |
1999 |
dc.identifier.citation |
William S. D. Wilcock, Spahr C. Webb, Ingi Þorleifur Bjarnason. (1999). The effect of local wind on seismic noise near 1 Hz at the MELT site and in Iceland. Bulletin of the Seismological Society of America, 89(6), 1543-1557. |
dc.identifier.uri |
https://hdl.handle.net/20.500.11815/572 |
dc.description.abstract |
The mantle electromagnetic and tomography (MELT) experiment on the
east Pacific rise near 17°S was the first large teleseismic experiment on a midocean
ridge. During the six-month deployment, no compressional arrivals were well recorded
above 0.5 Hz. In comparison, the ICEMELT experiment in Iceland recorded
compressional arrivals at 1-2 Hz from about 2 earthquakes per month. We compare
noise spectra from the two experiments and show that this difference in detection is
at least in part a result of noise. Near 1 Hz, seismic noise in the oceans is produced
locally by wind-generated waves. At both experiment sites, 1-Hz noise levels are
well correlated with local sea-surface-wind speeds derived from satellite observations.
For a given wind speed, 1-Hz noise levels are about 10-20 dB lower in Iceland.
At the MELT site, cross-correlations of wind speed with the logarithm of noise in a
narrow-frequency band yield correlation coefficients exceeding 0.7 at frequencies
between 0.4 Hz and 2 Hz. Noise levels at 1 Hz increase with wind by 1.3-1.4 dB
per m/sec for wind speeds less than 10 m/sec. For the ICEMELT experiment, high
correlation coefficients extend to markedly higher frequencies for coastal stations,
and there is a 10-dB drop in 1-Hz noise levels 100-km inland. Noise levels increase
by about 0.8 dB per m/sec. The strong correlation between wind speed and l-Hz
seismic noise provides justification for using satellite wind speed data to search for
locations on the global spreading system where there is a better probability of recording
high-frequency arrivals. The calmest sites are found on the northern east
Pacific rise, near the equator in all oceans, and near 34 ° N and 22 ° S on the mid-
Atlantic ridge. |
dc.description.sponsorship |
This study was supported by the National Science Foundation
under grant OCE-9414299. |
dc.format.extent |
1543-1557 |
dc.language.iso |
en |
dc.publisher |
The Seismological Society of America |
dc.relation.ispartofseries |
Bulletin of the Seismological Society of America;89(6) |
dc.rights |
info:eu-repo/semantics/openAccess |
dc.subject |
Jarðmöttull |
dc.subject |
Jarðeðlisfræði |
dc.subject |
Sneiðmyndatökur |
dc.subject |
Jarðskjálftar |
dc.subject |
Jarðskjálftamælingar |
dc.title |
The effect of local wind on seismic noise near 1 Hz at the MELT site and in Iceland |
dc.type |
info:eu-repo/semantics/article |
dc.description.version |
Peer Reviewed |
dc.identifier.journal |
Bulletin of the Seismological Society of America |
dc.contributor.department |
Raunvísindastofnun (HÍ) |
dc.contributor.department |
Science Institute (UI) |
dc.contributor.school |
Verkfræði- og náttúruvísindasvið (HÍ) |
dc.contributor.school |
School of Engineering and Natural Sciences (UI) |