Frequent excitations of T waves by earthquakes in the South Mariana Arc

Po Fei Chen, Kai Xun Chen, Hui Yun Cheng

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5 Scopus citations


We used broadband stations in Taiwan and on the Ryukyu Arc islands to investigate T waves induced by earthquakes in the Izu-Bonin-Mariana subduction zone. Of the 48 earthquakes that took place in 2005, 17 earthquakes exhibited T-wave signals consistent with predicted arrival times at stations. Of theses T-excited events, 13 were located in the South Mariana Arc, where the isobaths exhibit strong concave curvature, and were predominantly of normal faulting type. The energies of observed T waves were used quantitatively to evaluate the relative efficiency of receiver-side acoustic-elastic conversions by Gamma calculations. Results show that the steep slopes of offshore bathymetry together with nearly perpendicular angles of back azimuth relative to local isobaths are suitable conditions for T waves observations. In 2010, two clusters of repeated moderate earthquakes in the north and south ends of the Mariana Arc displayed stark contrasts in terms of T-wave excitations despite their normal faulting type. Examining of this discrepancy indicate that a specific curvature together with a specific radiation pattern accounts for the frequent excitations of T waves from shallow earthquakes in the South Mariana Arc.

Original languageEnglish
Pages (from-to)50-60
Number of pages11
JournalJournal of Asian Earth Sciences
StatePublished - 1 Feb 2015


  • Broadband in Taiwan for seismology
  • F-net
  • South mariana arc
  • T wave


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