Automated detection and association of surface waves
An algorithm for the automatic detection and association of surface waves has been developed and tested over an 18 month interval on broad band data from the Yellowknife array (YKA). The detection algorithm uses a conventional STA/LTA scheme on data that have been narrow band filtered at 20 s period...
Published in: | Annals of Geophysics |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
1994
|
Subjects: | |
Online Access: | https://doi.org/10.4401/ag-4208 https://doaj.org/article/048d9f4e1d044843b94c8c14e30e3a1c |
id |
ftdoajarticles:oai:doaj.org/article:048d9f4e1d044843b94c8c14e30e3a1c |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:048d9f4e1d044843b94c8c14e30e3a1c 2023-05-15T16:59:28+02:00 Automated detection and association of surface waves C. R. D. Woodgold R. G. North 1994-06-01T00:00:00Z https://doi.org/10.4401/ag-4208 https://doaj.org/article/048d9f4e1d044843b94c8c14e30e3a1c EN eng Istituto Nazionale di Geofisica e Vulcanologia (INGV) http://www.annalsofgeophysics.eu/index.php/annals/article/view/4208 https://doaj.org/toc/1593-5213 https://doaj.org/toc/2037-416X doi:10.4401/ag-4208 1593-5213 2037-416X https://doaj.org/article/048d9f4e1d044843b94c8c14e30e3a1c Annals of Geophysics, Vol 37, Iss 3 (1994) surface wave detection association automated detection azimuth determination Meteorology. Climatology QC851-999 Geophysics. Cosmic physics QC801-809 article 1994 ftdoajarticles https://doi.org/10.4401/ag-4208 2022-12-30T22:06:07Z An algorithm for the automatic detection and association of surface waves has been developed and tested over an 18 month interval on broad band data from the Yellowknife array (YKA). The detection algorithm uses a conventional STA/LTA scheme on data that have been narrow band filtered at 20 s periods and a test is then applied to identify dispersion. An average of 9 surface waves are detected daily using this technique. Beamforming is applied to determine the arrival azimuth; at a nonarray station this could be provided by poIarization analysis. The detected surface waves are associated daily with the events located by the short period array at Yellowknife, and later with the events listed in the USGS NEIC Monthly Summaries. Association requires matching both arrival time and azimuth of the Rayleigh waves. Regional calibration of group velocity and azimuth is required. . Large variations in both group velocity and azimuth corrections were found, as an example, signals from events in Fiji Tonga arrive with apparent group velocities of 2.9 3.5 krn/s and azimuths from 5 to + 40 degrees clockwise from true (great circle) azimuth, whereas signals from Kuriles Kamchatka have velocities of 2.4 2.9 km/s and azimuths off by 35 to 0 degrees. After applying the regional corrections, surface waves are considered associated if the arrival time matches to within 0.25 km/s in apparent group velocity and the azimuth is within 30 degrees of the median expected. Over the 18 month period studied, 32% of the automatically detected surface waves were associated with events located by the Yellowknife short period array, and 34% (1591) with NEIC events; there is about 70% overlap between the two sets of events. Had the automatic detections been reported to the USGS, YKA would have ranked second (after LZH) in terms of numbers of associated surface waves for the study period of April 1991 to September 1992. Article in Journal/Newspaper Kamchatka Yellowknife Directory of Open Access Journals: DOAJ Articles Tonga ENVELOPE(7.990,7.990,63.065,63.065) Yellowknife Annals of Geophysics 37 3 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
surface wave detection association automated detection azimuth determination Meteorology. Climatology QC851-999 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
surface wave detection association automated detection azimuth determination Meteorology. Climatology QC851-999 Geophysics. Cosmic physics QC801-809 C. R. D. Woodgold R. G. North Automated detection and association of surface waves |
topic_facet |
surface wave detection association automated detection azimuth determination Meteorology. Climatology QC851-999 Geophysics. Cosmic physics QC801-809 |
description |
An algorithm for the automatic detection and association of surface waves has been developed and tested over an 18 month interval on broad band data from the Yellowknife array (YKA). The detection algorithm uses a conventional STA/LTA scheme on data that have been narrow band filtered at 20 s periods and a test is then applied to identify dispersion. An average of 9 surface waves are detected daily using this technique. Beamforming is applied to determine the arrival azimuth; at a nonarray station this could be provided by poIarization analysis. The detected surface waves are associated daily with the events located by the short period array at Yellowknife, and later with the events listed in the USGS NEIC Monthly Summaries. Association requires matching both arrival time and azimuth of the Rayleigh waves. Regional calibration of group velocity and azimuth is required. . Large variations in both group velocity and azimuth corrections were found, as an example, signals from events in Fiji Tonga arrive with apparent group velocities of 2.9 3.5 krn/s and azimuths from 5 to + 40 degrees clockwise from true (great circle) azimuth, whereas signals from Kuriles Kamchatka have velocities of 2.4 2.9 km/s and azimuths off by 35 to 0 degrees. After applying the regional corrections, surface waves are considered associated if the arrival time matches to within 0.25 km/s in apparent group velocity and the azimuth is within 30 degrees of the median expected. Over the 18 month period studied, 32% of the automatically detected surface waves were associated with events located by the Yellowknife short period array, and 34% (1591) with NEIC events; there is about 70% overlap between the two sets of events. Had the automatic detections been reported to the USGS, YKA would have ranked second (after LZH) in terms of numbers of associated surface waves for the study period of April 1991 to September 1992. |
format |
Article in Journal/Newspaper |
author |
C. R. D. Woodgold R. G. North |
author_facet |
C. R. D. Woodgold R. G. North |
author_sort |
C. R. D. Woodgold |
title |
Automated detection and association of surface waves |
title_short |
Automated detection and association of surface waves |
title_full |
Automated detection and association of surface waves |
title_fullStr |
Automated detection and association of surface waves |
title_full_unstemmed |
Automated detection and association of surface waves |
title_sort |
automated detection and association of surface waves |
publisher |
Istituto Nazionale di Geofisica e Vulcanologia (INGV) |
publishDate |
1994 |
url |
https://doi.org/10.4401/ag-4208 https://doaj.org/article/048d9f4e1d044843b94c8c14e30e3a1c |
long_lat |
ENVELOPE(7.990,7.990,63.065,63.065) |
geographic |
Tonga Yellowknife |
geographic_facet |
Tonga Yellowknife |
genre |
Kamchatka Yellowknife |
genre_facet |
Kamchatka Yellowknife |
op_source |
Annals of Geophysics, Vol 37, Iss 3 (1994) |
op_relation |
http://www.annalsofgeophysics.eu/index.php/annals/article/view/4208 https://doaj.org/toc/1593-5213 https://doaj.org/toc/2037-416X doi:10.4401/ag-4208 1593-5213 2037-416X https://doaj.org/article/048d9f4e1d044843b94c8c14e30e3a1c |
op_doi |
https://doi.org/10.4401/ag-4208 |
container_title |
Annals of Geophysics |
container_volume |
37 |
container_issue |
3 |
_version_ |
1766051738368868352 |