T‐waves excited by S‐waves and oscillated within the ocean above the Southeastern Taiwan Forearc

Lin, Chu‐Hsing

doi:10.1029/2001gl013152

Cited by 11 publications

(10 citation statements)

References 10 publications

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“…Note the relatively early arrivals of the predicted T-waves can be considered as part of T-wave segments are propagating inside solid earth and the seismic wave propagation in faster velocity than acoustic wave at sea. bathymetry (the ocean-water interface) in trapping acoustic energy inside the low-velocity waveguide (SOFAR channel) is a fundamental aspect of the conversion of seismic energy into acoustic waves at the event source location, the T-waves themselves, however, are considered to represent acoustic energy that was converted from the P-or Lg-phases originating from shallow seismic events (Koyanagi et al 1995;Talandier and Okal 1998), or alternatively, from the S-waves originating from deep earthquakes (Okal and Talandier 1997;Lin 2001). Early named this model as the downslope conversion model, it was originally proposed to explain many attributes of the observed T-waves, and this model proved to be quite adequate in doing so (Officer 1958;Johnson et al 1963).…”

Section: Discussionmentioning

confidence: 99%

“…The 'T' in T-phase (and T-wave) denotes 'tertiary' because these waves are the third type to arrive, after P-(primary) and S-(secondary) waves which propagate instead through the Earth's crust; as a rule, Tphases are recorded at sea using hydrophones. However, the seismic conversion wave generated by a T-phase that strikes an island or continental shore can also be recorded by a seismometer on land (Shurbet 1955;Galanopoulos and Drakopoulos 1974;Lin 2001;Huang et al 2011).…”

Section: Introductionmentioning

confidence: 99%

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Observations of Earthquake-Generated T-Waves in the South China Sea: Possible Applications for Regional Seismic Monitoring

Huang

Shih²,

Lai³

et al. 2013

Terr. Atmos. Ocean. Sci.

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We present a detailed study of T-waves originating from earthquakes in the South China Sea region, near the Indochina Peninsula and Luzon islands which were recorded by a broadband seismic station at Nansha Island. Most of these T-waves appear to have been the source originating from earthquakes with epicentral distances greater than 600 km from this station. The T-waves in this region were identified via their apparent stable measured velocities of about 1.45 km s -1 , and represent the first reported T-waves and the first T-waves observed from an island station in the South China Sea. However, during the period of analysis (November 2004 to December 2005) additional earthquakes also occurred beyond the South China Sea region, but in these instances, any associated T-waves were not picked up by the station at Nansha Island. An analysis of Twave travel times reveals the possible locations of the P-wave to T-wave transitions at the ocean to crust interface were presumably situated near the earthquake source side. Our results indicate that the Sound Fixing and Ranging (SOFAR) channel is well developed in the South China Sea region. Ultimately, developing a solid understanding of the effective transmission of T-waves through the ocean may provide new opportunities for detecting and locating small earthquakes which would be useful for both seismic monitoring and in helping to predict and reduce the damaging effects of earthquakes and tsunamis in the South China Sea region.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Observations of Earthquake-Generated T-Waves in the South China Sea: Possible Applications for Regional Seismic Monitoring

Huang

Shih²,

Lai³

et al. 2013

Terr. Atmos. Ocean. Sci.

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“…Two different mechanisms have been identified to explain the T-wave coupling. 28 The first one is ''slope conversion,'' which is controlled by seafloor slope. 29,30 The second mechanism is scattering of energy into the sound channel at bathymetric promontories in close proximity to the source region.…”

Section: Influence Of Parametric Mode Conversion On Seaõ Bottom Comentioning

confidence: 99%

Long-range propagation of finite-amplitude acoustic waves in an ocean waveguide

Castor

Gerstoft

Roux

et al. 2004

The Journal of the Acoustical Society of America

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A hybrid method coupling nonlinear and linear propagation codes is used to study the nonlinear signature of long-range acoustic propagation for high-amplitude sources in an ocean waveguide. The differences between linear and nonlinear propagation are investigated in deep and shallow water environments. The spectral reshaping that occurs in nonlinear propagation induces two main effects: in shallow water, an unusual arrival time structure in the lowest order modes is observed, and in both shallow and deep water environments, there is a tendency to have acoustic energy more uniformly distributed across modes. Further, parametric low-frequency generation in deep water is a candidate for the coupling between water and sediments for T-wave formation.

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“…In recent years, several studies have reported T-phase observations in the Taiwan area using modern digital network observations (Chiu 1993;Lin 2001;Tu 2008;Wei 2010). Chiu (1993) reported the dominate frequencies of T phases recorded at Lu-Tao within 5 to 10 Hz.…”

Section: Introductionmentioning

confidence: 99%

“…Chiu (1993) reported the dominate frequencies of T phases recorded at Lu-Tao within 5 to 10 Hz. Both Lin (2001) and Tu (2008) reported the multiple path effects of T phase from eastern Taiwan offshore events. Wei (2010) reported T phases recorded in Taiwan inland stations from teleseismic events.…”

Section: Introductionmentioning

confidence: 99%

Investigation of T-Wave Propagation in the Offshore Area East of Taiwan from Early Analog Seismic Network Observations

Huang¹,

Chen²,

Huang³

et al. 2011

Terr. Atmos. Ocean. Sci.

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Extant paper records of the early analog seismic network of Taiwan represent a large resource for earthquake studies in several disciplines. In this study, we report on T waves generated from offshore earthquakes, based on analog observations. The T phases were identified from their stable apparent velocity of about 1.5 km s -1 and other observations using data recorded by stations in eastern Taiwan and on two nearby islands. The observed T phases are recorded for the first time from Taiwan, and in particular are observed by the network in the distal range of local earthquakes. Most of the T waves are observed at island stations at epicentral distances greater than 100 km. For earthquakes that occurred a great distance east of Taiwan, the T phases are always the most dominant phases observed at island stations east of Taiwan, and are also seen at some inland stations with smaller amplitudes. No T phases from inland events were observed by stations on Taiwan or on nearby islands. The observations indicate that the amplitude of the T phase is highly attenuated on its land path and that the propagation direction of the T phase is affected by water depth.

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T‐waves excited by S‐waves and oscillated within the ocean above the Southeastern Taiwan Forearc

Cited by 11 publications

References 10 publications

Observations of Earthquake-Generated T-Waves in the South China Sea: Possible Applications for Regional Seismic Monitoring

Observations of Earthquake-Generated T-Waves in the South China Sea: Possible Applications for Regional Seismic Monitoring

Long-range propagation of finite-amplitude acoustic waves in an ocean waveguide

Investigation of T-Wave Propagation in the Offshore Area East of Taiwan from Early Analog Seismic Network Observations

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