| Abstract: | In the classic microseismic band of 5-20 sec, seismic noise consists mainly of fundamental mode Rayleigh and Love waves; however, at shorter periods seismic noise also contains a significant amount of body-wave energy and higher mode surface waves. In this study we perform a global survey of Earth‘s short-period seismic noise field with the goal of quantifying the relative contributions of these propagation modes. We examined a year‘s worth of vertical component data from 18 seismic arrays of the International Monitoring System that were sited in a variety of geologic environments. The apertures of the arrays varied from 2 to 28 km, constraining the periods we analyzed to 0.25-2.5 sec. Using frequency-wavenumber analysis we identified the apparent velocity for each sample of noise and classified its mode of propagation. The dominant component was found to be Lg, occurring in about 50% of the noise windows. Because Lg does not propagate across ocean-continent boundaries, this energy is most likely created in shallow water areas near coastlines. The next most common component was P-wave energy, which accounted for about 28% of the noise windows. These were split between regional P waves (Pn=Pg at 6%), mantle bottoming P waves (14%), and core-sensitive waves (PKP at 8%). This energy is mostly generated in deep water away from coastlines, with a region of the North Pacific centered at 165?? W and 40?? N being especially prolific. The remainder of the energy arriving in the noise consisted of Rg waves (28%), a large fraction of which may have a cultural origin. Hence, in contrast to the classic micro-seismic band of 5-20 sec, at shorter periods fundamental mode Rayleigh waves are the least significant component. |
| Genre: | Article |
| ProdID: | 70034610 |
| Citation Author: | Koper, K. D.; Seats, K.; Benz, H. |
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| Citation End Page: | 617 |
| Citation Issue: | 2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Bulletin of the Seismological Society of America |
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| Citation Number Of Pages: | 12 |
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| Citation Search Results Text: | On the composition of earth‘s short-period seismic noise field; 2010; Article; Journal; Bulletin of the Seismological Society of America; Koper, K. D.; Seats, K.; Benz, H. |
| Citation Start Page: | 606 |
| Citation Volume: | 100 |
| Citation Year: | 2010 |
| Type: | citation/reference |
| Text: | On the composition of earth‘s short-period seismic noise field; 2010; Article; Journal; Bulletin of the Seismological Society of America; Koper, K. D.; Seats, K.; Benz, H. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1785/0120090120 |
| Date Other: | Fri, 1 Jan 2010 00:00 -0600 |
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