Intelligent post processing of seismic events
The Intelligent Monitoring Systern (IMS) currently provides for joint processing of data from six arrays located in Northern and Central Europe. From experience with analyst review of events automatically defined by the IMS, we bave realized that the quality of the automatic event locations can be s...
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Istituto Nazionale di Geofisica e Vulcanologia, INGV
1994
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Online Access: | https://www.annalsofgeophysics.eu/index.php/annals/article/view/4209 https://doi.org/10.4401/ag-4209 |
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ftjaog:oai:ojs.annalsofgeophysics.eu:article/4209 2023-05-15T16:12:20+02:00 Intelligent post processing of seismic events Kvaerna, T. Ringdal, F. 1994-11-25 application/pdf https://www.annalsofgeophysics.eu/index.php/annals/article/view/4209 https://doi.org/10.4401/ag-4209 eng eng Istituto Nazionale di Geofisica e Vulcanologia, INGV https://www.annalsofgeophysics.eu/index.php/annals/article/view/4209/4278 https://www.annalsofgeophysics.eu/index.php/annals/article/view/4209 doi:10.4401/ag-4209 Annals of Geophysics; V. 37 N. 3 (1994) Annals of Geophysics; Vol. 37 No. 3 (1994) 2037-416X 1593-5213 seismology signal processing onset time event location 05.09.99. General or miscellaneous info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 1994 ftjaog https://doi.org/10.4401/ag-4209 2022-03-27T06:36:59Z The Intelligent Monitoring Systern (IMS) currently provides for joint processing of data from six arrays located in Northern and Central Europe. From experience with analyst review of events automatically defined by the IMS, we bave realized that the quality of the automatic event locations can be significantly improved if the event intervals are reprocessed with signal processing pararneters tuned to phases from events in the given region. The tuned processing parameters are obtained from off line analysis of events located in the region of interest. The primary goal of such intelligent post processing is to provide event definitions of a quality that minimizes the need for subsequent manual analysis. The first step in this post processing is to subdivide the arca to be monitored in order to identify sites of interest. Clearly, calibration will be the easiest and potential savings in manpower are the largest for areas of high, recurring seismicity. We bave identified 8 mining sites in Fennoscandia/NW Russia and noted that 65.6% of the events of ML > 2.0 in this region can be associated with one of these sites. This result is based on 1 year and a half of data. The second step is to refine the phase arrival and azimuth estimates using frequency filters and processing parameters that are tuned to the initial event location provided by the IMS. In this study, we have analyzed a set of 52 mining explosions from the Khibiny Massif mining area in the Kola peninsula of Russia. Very accurate locations of these events bave been provided by the seismologists from the Kola Regional Seismology Centre. Using an autoregressive likelihood technique we have been able to estimate onset times to an accuracy (standard deviation) of about 0.05 s for P phases and 0.15 0.20 s for S phases. Using fixed frequency bands, azimuth can be estimated to an accuracy (one standard deviation) of 0.9 degrees for the ARCESS array and 3 4 degrees for the small array recently established near Apatity on the Kola peninsula. The third step in the post processing is a relocation of the event, using refined arrivai times and recomputed azimuths from broad band flk analysis. By introducing region specific travel time corrections, a median error of 1.4 km from the reported location has been obtained. This should be compared to the median error of 10.8 km for the automatie IMS processing for these events. This improvement in location accuracy clearly demonstrates the usefulness of the intelligent post processing approach. Article in Journal/Newspaper Fennoscandia kola peninsula Annals of Geophysics (INGV, Istituto Nazionale di Geofisica e Vulcanologia) Kola Peninsula Khibiny ENVELOPE(33.210,33.210,67.679,67.679) Apatity ENVELOPE(33.403,33.403,67.564,67.564) Annals of Geophysics 37 3 |
institution |
Open Polar |
collection |
Annals of Geophysics (INGV, Istituto Nazionale di Geofisica e Vulcanologia) |
op_collection_id |
ftjaog |
language |
English |
topic |
seismology signal processing onset time event location 05.09.99. General or miscellaneous |
spellingShingle |
seismology signal processing onset time event location 05.09.99. General or miscellaneous Kvaerna, T. Ringdal, F. Intelligent post processing of seismic events |
topic_facet |
seismology signal processing onset time event location 05.09.99. General or miscellaneous |
description |
The Intelligent Monitoring Systern (IMS) currently provides for joint processing of data from six arrays located in Northern and Central Europe. From experience with analyst review of events automatically defined by the IMS, we bave realized that the quality of the automatic event locations can be significantly improved if the event intervals are reprocessed with signal processing pararneters tuned to phases from events in the given region. The tuned processing parameters are obtained from off line analysis of events located in the region of interest. The primary goal of such intelligent post processing is to provide event definitions of a quality that minimizes the need for subsequent manual analysis. The first step in this post processing is to subdivide the arca to be monitored in order to identify sites of interest. Clearly, calibration will be the easiest and potential savings in manpower are the largest for areas of high, recurring seismicity. We bave identified 8 mining sites in Fennoscandia/NW Russia and noted that 65.6% of the events of ML > 2.0 in this region can be associated with one of these sites. This result is based on 1 year and a half of data. The second step is to refine the phase arrival and azimuth estimates using frequency filters and processing parameters that are tuned to the initial event location provided by the IMS. In this study, we have analyzed a set of 52 mining explosions from the Khibiny Massif mining area in the Kola peninsula of Russia. Very accurate locations of these events bave been provided by the seismologists from the Kola Regional Seismology Centre. Using an autoregressive likelihood technique we have been able to estimate onset times to an accuracy (standard deviation) of about 0.05 s for P phases and 0.15 0.20 s for S phases. Using fixed frequency bands, azimuth can be estimated to an accuracy (one standard deviation) of 0.9 degrees for the ARCESS array and 3 4 degrees for the small array recently established near Apatity on the Kola peninsula. The third step in the post processing is a relocation of the event, using refined arrivai times and recomputed azimuths from broad band flk analysis. By introducing region specific travel time corrections, a median error of 1.4 km from the reported location has been obtained. This should be compared to the median error of 10.8 km for the automatie IMS processing for these events. This improvement in location accuracy clearly demonstrates the usefulness of the intelligent post processing approach. |
format |
Article in Journal/Newspaper |
author |
Kvaerna, T. Ringdal, F. |
author_facet |
Kvaerna, T. Ringdal, F. |
author_sort |
Kvaerna, T. |
title |
Intelligent post processing of seismic events |
title_short |
Intelligent post processing of seismic events |
title_full |
Intelligent post processing of seismic events |
title_fullStr |
Intelligent post processing of seismic events |
title_full_unstemmed |
Intelligent post processing of seismic events |
title_sort |
intelligent post processing of seismic events |
publisher |
Istituto Nazionale di Geofisica e Vulcanologia, INGV |
publishDate |
1994 |
url |
https://www.annalsofgeophysics.eu/index.php/annals/article/view/4209 https://doi.org/10.4401/ag-4209 |
long_lat |
ENVELOPE(33.210,33.210,67.679,67.679) ENVELOPE(33.403,33.403,67.564,67.564) |
geographic |
Kola Peninsula Khibiny Apatity |
geographic_facet |
Kola Peninsula Khibiny Apatity |
genre |
Fennoscandia kola peninsula |
genre_facet |
Fennoscandia kola peninsula |
op_source |
Annals of Geophysics; V. 37 N. 3 (1994) Annals of Geophysics; Vol. 37 No. 3 (1994) 2037-416X 1593-5213 |
op_relation |
https://www.annalsofgeophysics.eu/index.php/annals/article/view/4209/4278 https://www.annalsofgeophysics.eu/index.php/annals/article/view/4209 doi:10.4401/ag-4209 |
op_doi |
https://doi.org/10.4401/ag-4209 |
container_title |
Annals of Geophysics |
container_volume |
37 |
container_issue |
3 |
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1765997628468756480 |