A leaping, triggered sequence along a segmented fault: The 1951 ML 7.3 Hualien-Taitung earthquake sequence in eastern Taiwan

Kate Huihsuan Chen, Shinji Toda, Ruey Juin Rau

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

As the most destructive seismic episode ever known in eastern Taiwan, the 1951 ML 7.3 Hualien - Taitung earthquake series consisted of sequential ruptures along four distinct fault segments. It provides a good opportunity to study earthquake triggering processes along an active fault at an oblique arc-continent collision boundary. This sequence initiated on 21October 1951 with the ML 7.3 Hualien main shock and a group of M6+ aftershocks nearby. The ML 6.0 Chihshang earthquake occurred 34 days later and 100 km away from the main shock. The ML 7.3 Yuli earthquake followed 3 m later and 5 km away from the Chihshang event. Two days later, the ML 6.0 Taitung earthquake shocked a region 40 km away from the preceding M6 event and completed the sequence. The first triggered rupture outside the main shock area did not occur on the nearby Yuli fault segment but occurred 100 km away at the Chihshang fault. Calculations of static Coulomb stress change show that most of the major aftershocks were located in areas of enhanced static stress change. However, the stress transfer alone cannot explain triggering across 100 km. With the rate /state stress transfer model, we computed the temporal order of encouraged ruptures on different segments along the collision boundary. The results show that 34 days following the major shocks in Hualien, the Chihshang segment had a higher M6+ (M ≥: 6) earthquake probability due to its significantly higher (at least an order of magnitude) background seismicity rate than the other two segments. After the Chihshang event, the rate/state model predicted a higher M6+ earthquake probability in the Yuli segment, also matching the observation. In this case, the Yuli segment was triggered ahead of the Taitung segment because of its larger increase in Coulomb stress change.

Original languageEnglish
Article numberB02304
JournalJournal of Geophysical Research: Solid Earth
Volume113
Issue number2
DOIs
Publication statusPublished - 2008 Feb 4

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Taiwan
Earthquakes
earthquakes
earthquake
stress change
shock
rupture
aftershock
arc-continent collision
collisions
active fault
continents
seismicity
collision
arcs
rate

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

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abstract = "As the most destructive seismic episode ever known in eastern Taiwan, the 1951 ML 7.3 Hualien - Taitung earthquake series consisted of sequential ruptures along four distinct fault segments. It provides a good opportunity to study earthquake triggering processes along an active fault at an oblique arc-continent collision boundary. This sequence initiated on 21October 1951 with the ML 7.3 Hualien main shock and a group of M6+ aftershocks nearby. The ML 6.0 Chihshang earthquake occurred 34 days later and 100 km away from the main shock. The ML 7.3 Yuli earthquake followed 3 m later and 5 km away from the Chihshang event. Two days later, the ML 6.0 Taitung earthquake shocked a region 40 km away from the preceding M6 event and completed the sequence. The first triggered rupture outside the main shock area did not occur on the nearby Yuli fault segment but occurred 100 km away at the Chihshang fault. Calculations of static Coulomb stress change show that most of the major aftershocks were located in areas of enhanced static stress change. However, the stress transfer alone cannot explain triggering across 100 km. With the rate /state stress transfer model, we computed the temporal order of encouraged ruptures on different segments along the collision boundary. The results show that 34 days following the major shocks in Hualien, the Chihshang segment had a higher M6+ (M ≥: 6) earthquake probability due to its significantly higher (at least an order of magnitude) background seismicity rate than the other two segments. After the Chihshang event, the rate/state model predicted a higher M6+ earthquake probability in the Yuli segment, also matching the observation. In this case, the Yuli segment was triggered ahead of the Taitung segment because of its larger increase in Coulomb stress change.",
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A leaping, triggered sequence along a segmented fault : The 1951 ML 7.3 Hualien-Taitung earthquake sequence in eastern Taiwan. / Chen, Kate Huihsuan; Toda, Shinji; Rau, Ruey Juin.

In: Journal of Geophysical Research: Solid Earth, Vol. 113, No. 2, B02304, 04.02.2008.

Research output: Contribution to journalArticle

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