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Detection and Identification of Near Seismic Events by SeisComP3

This presentation discusses the configuration of the network, signals measured, and examples of detected events using SeisComP3. The report also analyzes the accuracy of localization and the influence of station distribution on detection.

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Detection and Identification of Near Seismic Events by SeisComP3

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  1. Detection and Identification of Near Seismic Events by SeisComP3 limited by a sparse distributed Seismic Network Thomas Burghardt, Friedrich-Schiller-Universität Jena 17. Januar 2013 User Group Meeting Potsdam GFZ

  2. Contents • Configuration of the network • Which signals are measured and which features the measurement has • Examples for detected events • The reported events • Conclusion

  3. How TSN and SX network is configured for SeisComP3?

  4. The outer stations stabilize the localization of regional, Mediterranean and teleseismic events

  5. The inner Stations are for the detection of the local events

  6. Grid Search Algorithm Parameter

  7. The outer domain for Grid Search is the ^default configuration of SC3

  8. The inner Grid Search has a dense grid point domain of R=0,0625° ca. 3000 Grid Points are investigated

  9. Which signals the network measures?

  10. Local earthquakes or mining events Mediterranean, Balcan Local blasts Teleseismic Events Local blasts or mining in Poland or northwest Germany Local blasts at Bavaria

  11. The ambiguity of the Grid Search Algorithm and of LocSAT

  12. Conclusion: There are different detection and location results at two computers with the same SC3 configuration. To my mind the cause depends on the not stabilized Grid Search Algorithm for near events and on the difficulties of LocSAT to localize teleseismic events with a regional velocity model.

  13. Is the localization error less for a denser distribution of the stations in the network ?

  14. Is answer seems to be no. Probably the influence of the S onsets and the unsufficient pick order provided by the Grid Search have a great portion to the false localization

  15. Examples P- und S Onsets

  16. Gräfenberg, Germany 05. Apr. 2012, blast SHM: 49,651 ; 11,406 , ML=1,7 S2: 49,84 ; 11,85 Neustadt am Kulm S1: 47,62 ; 12,82 Ramsau, Oberbayern wrong distant station TRPA (HU)

  17. Where is the array?

  18. Swabian Alp, Albstadt, Germany, Earthquake • 02. Jan. 2013 19:55 EMSC: 48,24 ; 9,01 ML=2,3 • S2: south. Nürnberg: 49,16 ; 10,91 P Onsets, BFO is absent, but the pick exists • S1: S Onsets Near Cannes after relocation after put out of the far station: TRPA : 42,97 ; 6,03

  19. S2: Grid Search takes the P Onsets

  20. S1: Grid Search collects the S Onsets

  21. S2: south Nürnberg, P-Onsets S1: Near Cannes, S-Onsets

  22. S2: vp=6,18 ; vpk=6,97km/s S1: vp=5,15 ; vpk=8,06 km/s In spite of S Onsets vpk: velocity of LocSAT after determination the hypocenter

  23. Freiburg/Breisgau, Germany, Earthquake • 01. Jan. 2013 05:48 EMSC: 48,37 ; 8,99 • ML=2,1 • S2: 48,30 ; 8,64 P Onsets • S1: 48,30 ; 8,63 P Onsets

  24. The Station BFO near of Epicenter stabilized the Location vp=6,89, vpk=7,38km/s, Res. of BFO: -0,1

  25. Only some grid cells take part for location?

  26. Plauen, Germany, Earthquake • 28. Dec. 2012 19:55 • SHM: 50,454 ; 12,225, ML=1,1,10,5km • S2: 50,46 ; 12,34 MLv=1,1 • S1: 50,45 ; 12,33 MLv=1,1 The best place for determination of hypocenter, because of the dense network

  27. The nearest station PLN is too far from epicenter

  28. The right location by manually picking and location

  29. S1: Automatic Regression line vp=4,32, vpk=6,37km/s The automatical onsets are spreading much Regression line for manual Picks vp=6,64km/s

  30. Legnica, Poland, 03. Jan. 2013, 22:25, mining event, EMSC: 51,39 ; 16,28 ML=2,9 • S2: 52,03 ; 19,77 P Onsets • S1: 48,73 ; 18,40 S Onsets

  31. P Onsets => 52,03 ; 19,77

  32. The emergent onsets are spreading much vp=7,36km/s, dev.fitting: 2,67s, bad location

  33. False Station SMOL, S Onsets for network stations: 48,73 ; 18,4

  34. Manually location by SHM, only with the S Onset of nearest Station the result is comparable to EMSC: 51,495 ; 15,904

  35. Novy Kostel, Czech, 07. Jan. 2013, 17:19 Earthquake • SHM: 50,231 ; 12,452, ML=1,8 • S2: 50,24 ; 12,45 ML=1,9 • S1: 50,23 ; 12,47 ML=1,9

  36. LocSAT gives some too high velocity: vpk=6,99km/s, vp=5,8km/s

  37. The errors show the high velocity location, the S Onsets are shown clearly.

  38. By the waveform the local earthquake is recognized distinctly

  39. A near blast at Most has another waveform

  40. The spectra of earthquake has a max. At 20 Hz, in contrast to 4 Hz for the blast Novy Kostel, Earthquake Most, Blast

  41. The regression line of Onsets are suitable for identifcation teleseismic events • Honshu, 29. Dec. 2012, 23:05 EMSC: 37,11 , 141,15 S2: 50,74 ; 13,67 187km s1: 50,85 ; 13,73 after removing Station SOP: 52,96 ; 17,00

  42. Vp=20,29, vpk=20,57km/s before the removing SOP, the last station

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