Reflexionsseismiska mätningar över Burträsk-förkastningen: Cross-dip stack Reflection seismic study of the post-glacial Burträsk fault: Cross-dip stack snd1099-3-1.0 https://doi.org/10.5878/qwm7-pz92 Swedish National Data Service Svensk nationell datatjänst Landing page https://www.solid-earth.net/2/9/2011/ Reflexionsseismiska mätningar över Burträsk-förkastningen: Cross-dip stack Reflection seismic study of the post-glacial Burträsk fault: Cross-dip stack snd1099-3-1.0 https://doi.org/10.5878/qwm7-pz92 Juhlin, Christopher Juhlin, Christopher Beckel, Ruth Beckel, Ruth Swedish National Data Service Svensk nationell datatjänst Landing page https://www.solid-earth.net/2/9/2011/ EARTH SCIENCE SEISMIC PROFILE fault fel geophysics geofysik Geology Geologi Geoscientific Information Geovetenskap In 2008, a 22 km long high resolution reflection seismic profile was acquired over the Burträsk fault in Northern Sweden. The Burträsk fault formed at the end of the last glacial, triggered by the rapid melting of the Scandinavian ice sheet and the following crustal rebound. The aim of the survey was to image the structure of the fault with depth. The profile followed existing roads resulting in a very crooked acquisition geometry. A list of the key acquisition parameters is given below. The dataset was first processed and published in 2011. In 2018, the dataset was reprocessed using an additional cross-dip correction step to improve the imaging of reflection with a dip component in the cross-profile direction. The following data files are available for downloading: 1) raw shot gathers (decoded and quality controlled, with geometry information in the headers) 2) original stacked section from Juhlin and Lund (2011) 3) cross-dip corrected stacked section from Beckel and Juhlin (2019) 4) cross-dip corrected migrated section from Beckel and Juhlin (2019) A short summary of the main processing steps for each dataset is given below. For a complete description, please refer to the above mentioned publications. Key acquisition parameters: Number of channels: 280 Near offset: 0 m Geophone spacing: 20 m Geophone type : 28 Hz single Nominal source spacing : 20 m Source type : VIBSIST Hit interval between hammer blows : 100-200 ms Sweeps per source point :3-4 Nominal fold : 140 Recording instrument : SERCEL 408L Sample rate : 1ms Field low cut : Out Field high cut : 400 Hz Record length : 23 s Profile length : 22 km Source points : 799 Dates acquired: 2008/08/05-2008/08/16 Short summary of the main processing steps: 1) BUR_shots_geom.sgy The raw shot records are pre-processed with VIBSIST decoding, quality control. Information about the shot and receiver geometry has been added to the trace headers. 2) BUR_original_stack.sgy The processing flow of the original data stack includes trace editing and balancing, spectral equalization, time-variant bandpass filtering, refraction and residual statics, horizontal median filtering, NMO correction, DMO correction, stacking and coherency filtering (for a complete description see Juhlin & Lund, 2011) 3) BUR_crossdip_stack.sgy The main processing steps of the crossdip stack are very similar to those of the original stack, including trace editing and balancing, spectral equalization, time-variant bandpass filtering, refraction and residual statics, horizontal median filtering, NMO correction, DMO correction, stacking and coherency filtering. Before DMO correction, an additional cross-dip correction step has been added. For a complete description see Beckel & Juhlin, 2019. 4) BUR_crossdip_mig.sgy The processing flow of the migrated section includes trace editing and balancing, spectral equalization, time-variant bandpass filtering, refraction and residual statics, horizontal median filtering, NMO correction, cross-dip correction, DMO correction, stacking, coherency filtering and migration (for a complete description see Beckel & Juhlin, 2019). This dataset contains the cross-dip stack of the Burträsk profile (Beckel & Juhlin, 2019). Processing steps for this data set: 1. Read decoded VIBSIST data 2. Bulk static shift to zero time 3. Apply geometry 4. Manual first-break picking 5. Trace balance: 0-3000 ms 6. Ground-roll and first-break muting in local time- frequency domain: 25 % threshold 7. Spectral equalization: 30 Hz window, 25-40-120-150 Hz bandpass 8. Time-variant bandpass filtering: 0-200 ms: 35-60-120-180 Hz 250-500 ms: 30-50-120-180 Hz 600-900 ms: 25-40-110-165 Hz 1100-3000 ms: 20-35-100-150 Hz 9. Refraction statics: floating datum, replacement velocity from model 10. Trace editing 11. Horizontal median filter: 11 traces, 5300 m s-1 and 3000 m s-1 12. Butterworth filter: 20-40-90-120 Hz 13. Spherical divergence correction: 0.8 tpower, 2.0 vpower 14. Velocity analysis 15. NMO correction: 40 % stretch mute 16. Residual statics 17. Cross-dip correction: 5400 m s-1 , 20 % taper; Velocity analysis 18. DMO correction; Velocity analysis 19. Stacking 20. FX deconvolution: 19 trace window 21. Trace balance Processed seismic data stored as one file for the entire seismic profile, according to SEG technical standard SEG-Y revision 1 (SEG-Y_r1.0, 2002); https://seg.org/Publications/SEG-Technical-Standards Reflexionsseismiska mätningar över Burträsk-förkastningen I norra Sverige År 2008 gjordes en reflexionsseismiska undersökning över Burträsk-förkastningen I norra Sverige. Förkastningen formades vid slutet av sista istiden när glaciärerna nedsmältade snabbt. Ändamålen av undersökningen var att avbilda förkastningens djupa strukturerna. Seismisk profilen följde befintliga vägar, vilket resulterade I en ganska slingrig geometri av profilen. Datasetet bearbetades och publicerades först av Juhlin & Lund (2011). I 2018 gjordes ett nytt bearbetning av som omfattade en ytterligare steg för att korrigera effekten av 3D profilgeometrin (Beckel & Juhlin, 2019). En mer detaljerad beskrivning av datasetet som inkluderar alla viktiga parametrar är tillgängligt på den engelska katalogsidan:https://snd.gu.se/en/catalogue/study/SND1099 Utförlig beskrivning av datasetet finns på den engelska katalogsidan: https://snd.gu.se/en/catalogue/study/SND1099 2008-08-05 2008-08-16 Sweden Sverige Numeric Text Geospatial Other Access to data through SND. Data are freely accessible. Åtkomst till data via SND. Data är fritt tillgängliga. openAccess Beckel, R. A. and Juhlin, C.: The cross-dip correction as a tool to improve imaging of crooked-line seismic data: a case study from the post-glacial Burträsk fault, Sweden. Accepted for publication in Solid Earth, Special Issue: Advances in seismic imaging across the scales, 2019. Beckel, R. A. and Juhlin, C.: The cross-dip correction as a tool to improve imaging of crooked-line seismic data: a case study from the post-glacial Burträsk fault, Sweden. Accepted for publication in Solid Earth, Special Issue: Advances in seismic imaging across the scales, 2019. 2019 Juhlin, C. and Lund, B.: Reflection seismic studies over the end-glacial Burträsk fault, Skellefteå, Sweden, Solid Earth, 2, 9–16, https://doi.org/10.5194/se-2-9-2011, 2011. Juhlin, C. and Lund, B.: Reflection seismic studies over the end-glacial Burträsk fault, Skellefteå, Sweden, Solid Earth, 2, 9–16, https://doi.org/10.5194/se-2-9-2011, 2011. 2011