Телефон: 522-81-45

Geoinformatika 2015; 2(54) : 46-51 (in Ukrainian)

SEISMIC TOMOGRAPHY BY SWEEP-FREQUENCY METHOD

P.V. Anakhov

State University of Telecommunications, 7 Solomenska Str., Kyiv 03110, Ukraine, e-mail: anakhov@rambler.ru

Purpose. The purpose of the paper is to demonstrate the application of seiches oscillations of the water mass with unstable but manageable frequency in seismic tomography, which eliminates the excitation of elastic waves requiring expensive percussion, explosion and vibration technologies; to develop methods for seismic tomography using the property of sweep-frequency seiches.
Design/methodology/approach. We discovered that frequency of seiches depends on water level as well as on the phase of stimulation wave. These properties were then used in methods for conducting seismic raying of the earth’s crust.
Findings. On the example of Lake Sevan, it was shown that depth-sweep of water, which changes the level from minimum to maximum and back, causes a corresponding long-term frequency-modulated sweep of seiches. On the example of Aral Sea, we showed that the phase shift of exciting wave with respect to the decaying seiche leads to a short-term phase-modulated sweep of a resulting wave.
Practical value/implications. We justified the advantages of seismic tomography using seiches: seiches allow man-made oscillation; microseisms of seiches origin are characterized by a long range; seiches modulate high-frequency microseisms, which allows us to interpret them jointly and to increase reliability of the received seismic signal; seiches allow controlled frequency sweep, making it possible to record the frequency response of an object environment.

Keywords: microseismogenic phenomena, phase modulation of seiches, frequency sweep, frequency modulation of seiches.

The full text of papers

References:

  1. Azernikova O.A. Poverhnostnye i vnutrennie sejshi ozera Sevan [Surface and internal seiches of Lake Sevan]. Izvestija ANArmjanskoj SSR. Nauki o Zemle [Proceedings of the National Academy of Sciences of Armenia: Earth Sciences Series], 1975, no. 1, pp. 97-101.
  2. Anakhov P.V. Vikoristannja mіkrosejsmogennih javishh dlja rozvantazhennja tektonіchnih napruzhen’ [Releasing of tectonic stresses by using microseismogenic phenomena]. Geophysical Journal, 2014, vol. 36, no. 5, pp. 128-142.
  3. Berg L. Aral’skoe more. Opyt fiziko-geograficheskoj monografii [Aral Sea. Experience of physic-geographic monograph]. Izvestija Turkmenskogo Otdelenija Imperatorskogo Russkogo Geograficheskogo Obshhestva, tom V. Nauchnye Rezul’taty Aral’skoj Jekspedicii, Issue 9. Saint Petersburg, Tipografiya M.M. Stasyulevicha, 1908, 580 p.
  4. GOST R 51901.13-2005 (MEK 61025:1990). Menedzhment riska. Analiz dereva neispravnostej [IEC 61025:1990. Risk management. Fault Tree Analysis]. Moscow, Standartinform, 2005, 16 p.
  5. Kapustian N.K., Rogozhin A.E., Susin O.A. Opyt sejsmicheskih nabljudenij vozdejstvij vetra na narushennyj massiv gornyh porod [Seismic observations of the wind effect on a faulted rock mass]. Izvestiya. Physics of the Solid Earth, 2004, no. 3, pp. 54-59.
  6. Pat. 86894 Ukrajina, MPK G01V 1/00. Sposib mikrojejsmichnogo rozviduvannja [Method of microseismic tomography]. Anakhov P.V. № u201309813; zajavl. 07.08.2013; opubl. 10.01.2014; Bjul. № 1.
  7. Pat. 87564 Ukrajina, MPK G01V 1/00. Sposib mikrojejsmichnogo rozviduvannja [Method of microseismic tomography]. Anakhov P.V. № u201310919; zajavl. 12.09.2013; opubl. 10.02.2014; Bjul. № 3.
  8. Pat. 92618 Ukrajina, MPK G01V 1/02. Sposib stymuljuvannja zmishhjen’ u fragmjentah sjejsmoaktyvnyh rozlomiv depresijnoji zony vodoshovyshha [Method for stimulation the displacement of fragments of seismically active faults of depressing zone of reservoir]. Anakhov P.V. № u2014 03017; zajavl. 25.03.2014; opubl. 26.08.2014, Bjul. № 16.
  9. Shahova E.V. Jekspress-metodika dlja opredelenija mikrosejsmicheskoj aktivnosti platformennyh territorij (na primere Arhangel’skoj oblasti). Avtoref. dis. … kand. fiz.-mat. nauk [Express method for determination the microseismic activity of platform areas (Arkhangelsk region as example). PhD]. Moscow, Institute of Geology, Karelian Research Center RAS, 2008, 24p.
  10. Sheriff R.E., Geldart L.P. Sejsmorazvedka [Seismic exploration]. Vol. 1. Moscow, Mir Publishers, 1987, 448 p.
  11. Judahin F.N., Kapustjan N.K., Antonovskaja G.N., Shahova E.V. Ob ispol’zovanii vetrovyh kolebanij sooruzhenij dlja sejsmicheskogo prosvechivanija [On the use of fluctuations of the structures by wind for seismic tomography]. Doklady RAN, 2005, vol. 402, no. 2, pp. 255-259.
  12. Kodomari S. On the Studies of the Periodic Motions in a Lake (2): Effect of the Lake Basin Shape on the Periodic Motion. Journal of the Faculty of Science, Hokkaido University, Series 7 (Geophysics), 1982, vol. 7, no. 2, pp. 185-226.
  13. Langbein W.B. Water budget. In: First fourteen years of lake Mead. Geological survey circular 346. Washington, D.C., 1954, pp. 8-10.
  14. Pat. 4,671,379 US, Int. Cl. G01V 1/40. Method and apparatus for generating seismic waves. Kennedy W.S., BlumenkranzS.J. Appl. No.: 771,719; Filed: 03.09.1985; Date of Patent: 09.06.1987.
  15. Rabinovich A.B. Seiches and Harbor Oscillations. In: Handbook of Coastal and Ocean Engineering (ed. by Y. C. Kim). Singapoure, World Scientific Publ., 2009, pp. 193-236.