T waves from the 1998 Papua New Guinea earthquake and its aftershocks: Timing the Tsunamigenic slump

Emile A. Okal

doi:10.1007/s00024-003-2409-x

T waves from the 1998 Papua New Guinea earthquake and its aftershocks: Timing the Tsunamigenic slump

Emile A. Okal^*

^*Corresponding author for this work

Earth and Planetary Sciences

Research output: Contribution to journal › Article › peer-review

45 Scopus citations

Abstract

T waves recorded at hydrophone and seismic stations following the Papua New Guinea earthquake of 17 July 1998 and its aftershocks show that a small event at 09:02 GMT featured source properties incompatible with an elastic dislocation of appropriate body-wave magnitude (m_b = 4.4). These include an exceptional duration (47 s at the Wake Island hydrophone station WK31), a spectrum rich in high frequencies (7 to 12 Hz), and a generally low spectral amplitude. These characteristics can be explained by the model of an underwater slump, accelerating from a standstill and eventually slowing down. The relocation of the 09:02 event is compatible with its location within an amphitheater inside which shipboard cruises in 1998 and 1999 documented the presence of a 4 - km³ geologically fresh slump. We propose that the slump took place at 09:02 on 17 July 1998, i.e., 13 minutes after the mainshock, and that it generated the locally catastrophic tsunami, whose properties (amplitude and distribution of runup; timing) could not be explained by a dislocation model.

Original language	English (US)
Pages (from-to)	1843-1863
Number of pages	21
Journal	Pure and Applied Geophysics
Volume	160
Issue number	10-11
DOIs	https://doi.org/10.1007/s00024-003-2409-x
State	Published - Oct 2003

Funding

I thank Costas Synolakis for arranging my participation in the Post-Tsunami Field Survey (under funding from the National Science Foundation), and for many subsequent discussions. I am grateful to an anonymous reviewer for constructive comments. T -wave records used in this study were obtained from the IRIS data management center, the POSEIDON data center, the Prototype International Data Center of the Comprehensive Nuclear Test Ban Treaty, or kindly provided by Cecily Wolfe (PELEnet), Jesse Williams (MBARI), and Bor-Shouh Huang (Taiwan network). Several figures were drawn using the GMT software (WESSEL and SMITH, 1991). Some aspects of this research were supported by the Defense Threat Reduction Agency, under contract DTRA01-00-C-0065.

Keywords

Landslides
T waves
Tsunamis

ASJC Scopus subject areas

Geophysics
Geochemistry and Petrology

Access to Document

10.1007/s00024-003-2409-x

Cite this

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title = "T waves from the 1998 Papua New Guinea earthquake and its aftershocks: Timing the Tsunamigenic slump",

abstract = "T waves recorded at hydrophone and seismic stations following the Papua New Guinea earthquake of 17 July 1998 and its aftershocks show that a small event at 09:02 GMT featured source properties incompatible with an elastic dislocation of appropriate body-wave magnitude (mb = 4.4). These include an exceptional duration (47 s at the Wake Island hydrophone station WK31), a spectrum rich in high frequencies (7 to 12 Hz), and a generally low spectral amplitude. These characteristics can be explained by the model of an underwater slump, accelerating from a standstill and eventually slowing down. The relocation of the 09:02 event is compatible with its location within an amphitheater inside which shipboard cruises in 1998 and 1999 documented the presence of a 4 - km3 geologically fresh slump. We propose that the slump took place at 09:02 on 17 July 1998, i.e., 13 minutes after the mainshock, and that it generated the locally catastrophic tsunami, whose properties (amplitude and distribution of runup; timing) could not be explained by a dislocation model.",

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author = "Okal, {Emile A.}",

note = "Funding Information: I thank Costas Synolakis for arranging my participation in the Post-Tsunami Field Survey (under funding from the National Science Foundation), and for many subsequent discussions. I am grateful to an anonymous reviewer for constructive comments. T -wave records used in this study were obtained from the IRIS data management center, the POSEIDON data center, the Prototype International Data Center of the Comprehensive Nuclear Test Ban Treaty, or kindly provided by Cecily Wolfe (PELEnet), Jesse Williams (MBARI), and Bor-Shouh Huang (Taiwan network). Several figures were drawn using the GMT software (WESSEL and SMITH, 1991). Some aspects of this research were supported by the Defense Threat Reduction Agency, under contract DTRA01-00-C-0065.",

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N1 - Funding Information: I thank Costas Synolakis for arranging my participation in the Post-Tsunami Field Survey (under funding from the National Science Foundation), and for many subsequent discussions. I am grateful to an anonymous reviewer for constructive comments. T -wave records used in this study were obtained from the IRIS data management center, the POSEIDON data center, the Prototype International Data Center of the Comprehensive Nuclear Test Ban Treaty, or kindly provided by Cecily Wolfe (PELEnet), Jesse Williams (MBARI), and Bor-Shouh Huang (Taiwan network). Several figures were drawn using the GMT software (WESSEL and SMITH, 1991). Some aspects of this research were supported by the Defense Threat Reduction Agency, under contract DTRA01-00-C-0065.

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N2 - T waves recorded at hydrophone and seismic stations following the Papua New Guinea earthquake of 17 July 1998 and its aftershocks show that a small event at 09:02 GMT featured source properties incompatible with an elastic dislocation of appropriate body-wave magnitude (mb = 4.4). These include an exceptional duration (47 s at the Wake Island hydrophone station WK31), a spectrum rich in high frequencies (7 to 12 Hz), and a generally low spectral amplitude. These characteristics can be explained by the model of an underwater slump, accelerating from a standstill and eventually slowing down. The relocation of the 09:02 event is compatible with its location within an amphitheater inside which shipboard cruises in 1998 and 1999 documented the presence of a 4 - km3 geologically fresh slump. We propose that the slump took place at 09:02 on 17 July 1998, i.e., 13 minutes after the mainshock, and that it generated the locally catastrophic tsunami, whose properties (amplitude and distribution of runup; timing) could not be explained by a dislocation model.

AB - T waves recorded at hydrophone and seismic stations following the Papua New Guinea earthquake of 17 July 1998 and its aftershocks show that a small event at 09:02 GMT featured source properties incompatible with an elastic dislocation of appropriate body-wave magnitude (mb = 4.4). These include an exceptional duration (47 s at the Wake Island hydrophone station WK31), a spectrum rich in high frequencies (7 to 12 Hz), and a generally low spectral amplitude. These characteristics can be explained by the model of an underwater slump, accelerating from a standstill and eventually slowing down. The relocation of the 09:02 event is compatible with its location within an amphitheater inside which shipboard cruises in 1998 and 1999 documented the presence of a 4 - km3 geologically fresh slump. We propose that the slump took place at 09:02 on 17 July 1998, i.e., 13 minutes after the mainshock, and that it generated the locally catastrophic tsunami, whose properties (amplitude and distribution of runup; timing) could not be explained by a dislocation model.

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T waves from the 1998 Papua New Guinea earthquake and its aftershocks: Timing the Tsunamigenic slump

Abstract

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ASJC Scopus subject areas

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