Küresel Konumlama Uydu Sistemleri Tabanlı Deprem Gözlemlerinin Duyarlığı

Öz

Bu çalışmada, sarsma tablası üzerinde farklı depremler için ivmeölçer ve Küresel Konumlama Uydu Sistemleri (KKUS) gözlemleri yapılmış ve gözlemler ile gerçek girdi arasındaki farklar zaman ve frekans ortamında incelenmiştir. Ölçülen KKUS yer değiştirme dalga formları ve ivme kayıtlarından elde edilen dalga formları gerçek girdi ile karşılaştırıldığında KKUS’un Karekök Ortalama (RMS) hata değerleri 4-9 mm arasında değişirken, ivme kayıtlarından elde edilen yer değiştirme dalga formlarının RMS değerleri 1-110 mm arasında değişmektedir. KKUS yer değiştirme dalga formlarının ortalama RMS değerleri ~6 mm civarındadır. Yapılan sinyal tutarlık analizlerinde, ivme kayıtları ile gerçek girdi sinyali arasındaki tutarlığın 2-3 Hz’den daha yüksek frekanslarda gözlendiği, düşük frekanslarda tutarlığın düşük olduğu buna karşın KKUS ile gerçek girdi sinyali arasındaki tutarlığın 1 Hz’e kadar olan düşük frekanslarda düz olduğu gözlenmektedir.

Anahtar Kelimeler

• KKUS,İvmeölçer,Yer değiştirme,RMS hata,Sinyal tutarlık analizi

Precision of Global Navigation Satellite Systems Based Earthquake Observations

Öz

In this study, accelerometer and GNSS observations were carried out for different earthquakes on the shake table and the differences between the observations and the actual input were examined in both time and frequency domains. When the waveforms obtained from the measured GNSS and acceleration displacement waveforms are compared with the actual input, the Root Mean Square (RMS) error values of GNSS vary between 4 and 9 mm while the RMS values of the displacement waveforms obtained from the acceleration records vary between 1 and 110 mm. Besides, the average RMS values of the GNSS displacement waveforms are around ~6 mm. In the signal coherence analysis, the coherence between the acceleration measurements and the actual input signal is observed only at frequencies higher than 2-3 Hz verifying that the coherence at lower frequencies is low for accelerometers whereas the coherence between GNSS and the actual input signal is observed to be flat at low frequencies up to 1 Hz. 

Anahtar Kelimeler

• GNSS,Acceleration,Displacement,RMS error,Signal coherence analysis

Kaynakça

1. Aktuğ B., 2005. Uyarlamalı filtrelerle gerçek zamanlı navigasyon, HKM Jeodezi Jeoinformasyon ve Arazi Yönetimi 92, 29-37.
2. Bendat J.S., Piersol A.G., 1986. Random data. Wiley-Interscience.
3. Bock Y., Crowell B., Melgar D., 2011. Real time GPS/Seismic and EEW Results from El Mayor Cucapah and Tohoku-oki Earthquakes. Earthquake Early Warning Summit: Delivering Earthquake Warnings to the U.S. West Coast. Berkeley.
4. Bock Y., Restrepo J., Melgar D., Offield D.G., 2012. Low-cost, strong motion sensor packages to obtain full spectrum waveforms for earthquake early warning and structural monitoring applications, NSF Final Report.
5. Boore D.M., 1999. Effect of Baseline Corrections on Response Spectra for Two Recordings of the 1999 Chi Chi, Taiwan Earthquake, Restron, USGS.
6. Boore D.M., 2001. Effect of baseline corrections on displacements and response spectra for several recordings of the 1999 Chi Chi, Taiwan earthquake, Bull. Seismol. Soc. Am. 91, 1199-1211.
7. Boore D.M., Bommer J., 2005. Processing of strong motion accelograms: Needs, options and consequences, Soil Dynamics and Earthquake Engineering 25, 93-115.
8. Boore D.M., Stephans C., Joyner B., 2002. Comments on baseline correction of digital strong-motion data: Examples from the 1999 Hector Mine, California earthquake, Bull. Seismol. Soc. Am. 92, 1543-1560.

9. Brown H. M., Allen R. M., Hellweg M., Khainovski O., Neuhauser D., Souf A., 2011. Development of the elarms methodology for earthquake early warning: Realtime application in California and offline testing in Japan, Soil Dynamics and Earthquake Engineering 31, 188-200.
10. Crowell B.W., Melgar D., Bock D., 2013. Earthquake magnitude scaling using seismogeodetic data, Geophysical Research Letter 40(23), 6089-6094.
11. Crowell B.W., Schmidt D.A., Bodin P., Vidale J.E., Baker B., Barrientos S., Geng J., 2018a. G-FAST earthquake early warning potential for great earthquakes in Chile, Seism. Res. Lett. 89, 542-556.
12. Crowell B.W., Melgar D., Geng J., 2018b. Hypothetical real-time GNSS modelling of the 2016 Mw 7.8 Kaikoura Earthquake: Perspectives from ground motion and tsunami inundation prediction, Bull. Seism. Soc. Am. 108, 1736-1745, doi: 10.1785/0120170247.
13. Gelb A., 1974. Applied optimal estimation. Massachusetts, MIT Press, USA.
14. Graizer V.M., 1979. Determination of the true ground displacement by using strong motion records, Earth Physics 15 (12), 875-885.
15. Graizer V.M., 2006. Tilts in strong motion, Bull Seism. Soc. Am. 96(6) 2090-2102.
16. Hartog J.R., Kress V.C., Malone S.D., Bodin P., Vidale J.E., Crowell B.W., 2016. Earthquake early warning: ShakeAlert in the Pacific Northwest, Bull. Seism. Soc. Am. 106, 1875-1886, doi: 10.1785/0120150261.
17. Hoshiba M., Iwakiri K., 2011. Initial 30 seconds of the 2011 off the Pacific coast of Tohoku Eartthquake (Mw 9.0)-amplitude and Tc for magnitude estimation for earthquake early warning, Earth, Planet and Space 63, 553-557, 2011.
18. Iwan W.D., Mooser M.A., Peng C.Y. 1985. Some observations on strong motion earthquake measuremenets using a digital accelerograph, Bull. Seism. Soc. Am. 75(5), 1225-1246. ISSN 0037-1106.
19. Kedar S., Watada S., Tanimoto T. 1994. The 1989 Macquarie Ridge earthquake: Seismic moment estimation from long period free oscillations, J. Geophys. Res. 99,17893-17908.
20. Liebelt P.B., 1967. An Introduction to Optimal Estimation. Massachusetts: Addison-Wesley. Merminod B., 1989. The Use of Kalman Filters in GPS Navigation, UNISRV, New South Wales, Australia.
21. Murray J.R., Crowell B.W., Grapenthin R., Hodgkinson K., Langbein J.O., Melbourne T., Melgar D., Minson S.E., Schmidt D.A., 2018, Development of a geodetic component for the U. S. West Coast earthquake early warning system, Seism. Res. Lett. 89, 2322-2336, doi: 10.1784/0220180162.
22. Nakamura Y., 1988. On the Urgent Earthquake Detection and Alarm System (UrEDAS), 9th world conference on earthquake engineering, Vol. VII, 673-678, 2-9 August 1988, Tokyo-Japan.
23. Olson E., Allen M., 2005. The deterministic nature of earthquake rapture, Nature 438, 212-215.
24. Park J., Song T., Tromp J., Okal E., Stein S., Roult G., Clevede E., Laske G., Kanamori H., Davis P., Berger J., Braitenberg C., Van Camp M., Lei X., Sun H., Xu H., Rosat S., 2005. Earthquakes frss oscillations excited by the 26 December 2004 Sumatra-Andaman earthquake, Science 308, 1139-1144, 20 May 2005.
25. Penny W.D., 2000. Signal Processing Course, Institute of Neurology, University College London, UK.
26. Pillet R., Virieux J. 2007. The effects of seismic rotations on inertial sensors, Geophysical Journal International 171(3), 1314-1323, doi: 10.1111/j.1365-246X.2007.03617.x
27. Ruhl C.J., Melgar D., Geng J., Goldberg D.E., Crowell B.W., Allen R.M., Bock Y., Barrientos S., Riquelme S., Baez J.C., Cabral-Cano E., Perez-Campos X., Hill E.M., Protti M., Ganas A., Ruiz M., Mothes P., Jarrin P., Nocquet J.M., Avouac J.P., D'Anastassio E., 2019. A global database of strong motion displacement GNSS recordings and an example application to PGD scaling, Seism. Res. Lett. 90(1), 271-279, doi: 10.1785/0220180177.
28. Schwarz K.P., Krynski J., 1989. Fundamentals of Geodesy, University of Calgary, Department of Surveying Engineering, 177p.
29. Strang G., Borre K., 1997. Linear algebra, geodesy, and GPS, Wellesley Press, ISBN 978-0961408862, Cambridge, 624p.
30. Wu Y., Kanamori H., 2005. Experiment on Onsite Early Warning Method for the Taiwan Early Warning System, Bull. Seismol. Soc. Am. 95(1), 347-353, doi: 10.1785/0120040097
31. Wu Y.M., Zhao L., 2006. Magnitude estimation using the first three seconds P-wave amplitude in earthquake early warning, Geophys. Res. Lett. 33, L16312. doi:10.1029/2006GL026871