• Title/Summary/Keyword: time-reversal invariance

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Imaging of Seismic Sources Using Time Reversal Wave Propagation (지진파 역행 전파를 이용한 지진원 영상화)

  • Sheen, Dong-Hoon;Baag, Chang-Eob;Hwang, Eui-Hong;Ryoo, Yong Gyu;Youn, Yong-Hoon
    • 한국지구물리탐사학회:학술대회논문집
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    • 2006.06a
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    • pp.181-186
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    • 2006
  • An imaging method of seismic sources using time-reversal wave propagation is presented. The method is based on the time-reversal invariance and the spatial reciprocity of the wave equation. Time-reversal wave propagation has been used to image anomalous features of a midium in medical imaging, non destructive testing and waveform tomography. Seismogram is the record whose energy is propagated from the seismic source. If time-reversed seismogram propagates back into the medium, seismic energy is concentrated at the origin time of the event and at the source location. In this work, a staggered-grid finite-difference method of the elastic wave equation is parallelized for 3-D wave propagation simulation. With numerical experiments, we show that the time-reversal imaging will enable us to explore the spatio-temporal history of complex earthquake.

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Imaging of seismic sources by time-reversed wave propagation with staggered-grid finite-difference method (지진원 영상화를 위한 엇갈린 격자 유한 차분법을 이용한 지진파 역행 전파 모의)

  • Sheen, Dong-Hoon;Hwang, Eui-Hong;Ryoo, Yong-Gyu;Youn, Yong-Hoon
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2006.03a
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    • pp.25-32
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    • 2006
  • We present a imaging method of seismic sources by time reversal propagation of seismic waves. Time-reversal wave propagation is actively used in medical imaging, non destructive testing and waveform tomography. Time-reversal wave propagation is based on the time-reversal invariance and the spatial reciprocity of the wave equation. A signal is recorded by an array of receivers, time-reversed and then back-propagated into the medium. The time-reversed signal propagates back into the same medium and the energy refocuses back at the source location. The increasing power of computers and numerical methods makes it possible to simulate more accurately the propagation of seismic waves in heterogenous media. In this work, a staggered-grid finite-difference solution of the elastic wave equation is employed for the wave propagation simulation. With numerical experiments, we show that the time-reversal imaging will enable us to explore the spatio-temporal history of complex earthquake.

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