Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/3692
DC FieldValueLanguage
dc.contributor.authorallWang, J.; University of Cambridge, U. K.en
dc.contributor.authorallTilmann, F.; University of Cambridge, U. K.en
dc.contributor.authorallWhite, R. S.; University of Cambridge, U. K.en
dc.contributor.authorallSoosalu, H.; University of Cambridge, U. K.en
dc.contributor.authorallBordoni, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italiaen
dc.date.accessioned2008-03-06T09:54:37Zen
dc.date.available2008-03-06T09:54:37Zen
dc.date.issued2008-02en
dc.identifier.urihttp://hdl.handle.net/2122/3692en
dc.description.abstractWe are concerned with the detection and location of small seismic events, such as can be encountered in monitoring hydro-fracturing with surface sensors. Ambient seismic noise is the main problem in detection of weak seismic phases from these events, particularly as the sites of interest are often within or near producing fields. Band-pass filtering and stacking are the most widely used techniques for enhancing the signal-to-noise ratio (SNR) in passive seismic experiments, but they are of limited value when noise and signal share the same frequency band. Seismic arrays can be used to reduce the unwanted noise (e.g., traffic noise, pumping noise, scattering ground roll) by delay-and-sum techniques (also called beamforming) or by frequencywavenumber filtering. Beamforming maximizes the array response for the assumed direction and slowness of the signal. Whereas in some situations it can be highly effective, and the azimuth and slowness of the signal can be determined by a grid search approach, it is vulnerable to contamination by side-lobe energy, particularly for broadband signals and noise (Rost and Thomas, 2002). Frequencywavenumber filtering can be very effective but requires regularly spaced arrays and implicitly assumes plane-wave propagation. Both methods perform poorly when the waveform changes significantly between stations of the array, as might be caused, for example, by differences in site response. In this article, we present a multichannel Wiener filtering technique, which allows the removal of coherent noise from three-component 2D arrays without making a priori assumptions about the mode of propagation (e.g., no planewave assumption is required for the noise field). We test the effectiveness of this filter with two case studies. In the first case, we add synthetic signals of varying strengths to actual noise data recorded with a hexagonal array during hydrofracturing within a producing oil field in Wyoming, USA. Using this test, we are able to provide estimates of the smallest event detectable with the filtered data, and compare the results with conventional techniques, such as stacking. The second test case is a dense, small-aperture 2D seismic array of 95 stations placed within an area of 130 m 56 m on a landslide deposit in the Northern Apennines, Italy. Numerous microearthquakes have been recorded with this array, whose faint P-phases serve as an ideal data set for testing filtering techniques. Using the two case studies, we discuss the effectiveness of the multichannel Wiener filter on SNR improvement, and show that including horizontal components into the analysis increases the SNR improvement more than using only vertical components.en
dc.description.sponsorshipAcknowledgments: We thank Schlumberger Cambridge Research for providing funding for this project and for the hydrofracture surface monitoring experiment. However, the views expressed here are those of the authors, who are solely responsible for any errors. For the hydrofracture surface data, we thank the Schlumberger office in Rock Springs, Wyoming, for help with logistics and deployment, BP for permission to deploy seismometers on one of their fields, Anna Horleston and Sharif Aboelnaga for assistance in the field, and SEIS-UK for the loan of the seismometers. The Cavola data were acquired by the Istituto Nazionale di Geofisica e Vulcanologia, Italy. We thank the Cavola Experiment Team, particularly John Haines (University of Cambridge), Giuliano Milana, Giuseppe Di Giulio and Fabrizio Cara (Istituto Nazionale di Geofisica e Vulcanologia). Ed Kragh and Everhard Muyzert provided helpful advice. University of Cambridge, Department of Earth Sciences contribution No. ES9031.en
dc.language.isoEnglishen
dc.relation.ispartofTHE LEADING EDGEen
dc.relation.ispartofseries2/27 (2008)en
dc.subjectseismic noiseen
dc.subjectWiener filtersen
dc.titleApplication of multichannel Wiener filters to the suppression of ambient seismic noise in passive seismic arraysen
dc.typearticleen
dc.description.statusPublisheden
dc.type.QualityControlPeer-revieweden
dc.description.pagenumber232-238en
dc.subject.INGV04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniquesen
dc.description.obiettivoSpecifico1.1. TTC - Monitoraggio sismico del territorio nazionaleen
dc.description.journalTypeN/A or not JCRen
dc.description.fulltextpartially_openen
dc.contributor.authorWang, J.en
dc.contributor.authorTilmann, F.en
dc.contributor.authorWhite, R. S.en
dc.contributor.authorSoosalu, H.en
dc.contributor.authorBordoni, P.en
dc.contributor.departmentUniversity of Cambridge, U. K.en
dc.contributor.departmentUniversity of Cambridge, U. K.en
dc.contributor.departmentUniversity of Cambridge, U. K.en
dc.contributor.departmentUniversity of Cambridge, U. K.en
dc.contributor.departmentIstituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione ONT, Roma, Italiaen
item.openairetypearticle-
item.cerifentitytypePublications-
item.languageiso639-1en-
item.grantfulltextrestricted-
item.openairecristypehttp://purl.org/coar/resource_type/c_18cf-
item.fulltextWith Fulltext-
crisitem.author.deptUniversity of Cambridge, U. K.-
crisitem.author.deptUniversity of Cambridge, Bullard Laboratories-
crisitem.author.deptUniversity of Cambridge, U. K.-
crisitem.author.deptIstituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione Roma1, Roma, Italia-
crisitem.author.orcid0000-0002-3391-4402-
crisitem.author.parentorgIstituto Nazionale di Geofisica e Vulcanologia-
crisitem.classification.parent04. Solid Earth-
crisitem.department.parentorgIstituto Nazionale di Geofisica e Vulcanologia-
Appears in Collections:Article published / in press
Files in This Item:
File Description SizeFormat Existing users please Login
jwang2008amw.pdfmain article537.09 kBAdobe PDF
text_13Dec.pdfmanuscript664.58 kBAdobe PDFView/Open
Show simple item record

Page view(s) 50

198
checked on Apr 24, 2024

Download(s) 5

1,322
checked on Apr 24, 2024

Google ScholarTM

Check