open access

https://doi.org/10.14943/gbhu.69.15

https://hdl.handle.net/2115/21497

Muti-orbit surface waves generated by the 2004 great Sumatra earchquake

日本語

2006-03-15

北海道大学大学院理学研究科地球惑星科学専攻（地球物理学）

Geophysical bulletin of Hokkaido University

69

15-21

The great Sumatra earchquake on December 26, 2004, which devastated the coastal areas of the Indian Ocean by the subsequent tsunami, generated tremendous numbers of surface-wave trains which traveled around the globe for many times. We analyse vertical-component seismograms of the event recorded by the F-net broadband seismic network in Japan, which has been deployed and maintained by NIED (National Research Institute for Earth Science and Disaster Prevention, Japan). By applying a band-pass filter between 3 and 5 mHz, we extract the long-period Airy phase of the fundamental-mode Rayleigh wave. The long period records display a magnificent series of multi-orbit Rayleigh wave trains that have circumnavigated the Earth for more than 6 times; i.e., we are able to observe clear signals up to R13-R14 phases. Although much later arrival phases than R14 become less visible mainly due to lateral heterogeneities in the Earth as well as dispersions of surface waves, we are still able to detect some smaal signals up to R18.

紀要論文

Version of Record

0439-3503

AN0008976X