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IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS002 Oral Presentation 1739
Tsunami associated with the Mw 7.1 earthquake over Luzon Strait on 26
December 2006
Dr. Wing Tak Wong
Geophysics, Time and Port Meteorological Services Hong Kong Observatory IASPEI
Kin-Wai Li, Mr Wang-Chun Woo
At 20:26 Hong Kong Time on 26 December 2006, an earthquake of moment magnitude Mw 7.1 (Ms
7.2) occurred over the Luzon Strait near Taiwan Island. The earthquake wreaked havoc in Hengchun,
Taiwan and damaged many submarine telecommunication fibre cables in the Luzon Strait which
connected Hong Kong to overseas. At a distance of more than 600 kilometres from the epicentre, many
residents in Hong Kong felt the earth tremor. Based on reports from local residents, the intensity at
Hong Kong was III to IV on the Modified Mercalli Intensity Scale. The peak ground acceleration
measured by strong motion accelerographs at Hong Kong was 0.003 to 0.004 g. After the occurrence of
the earthquake, the Hong Kong Observatory issued a Tsunami Information Bulletin, the first of its kind,
to advise the people of Hong Kong that the earthquake might have generated a tsunami but the
tsunami height at Hong Kong would not be significant. At Tai Miu Wan tide gauge station in the eastern
part of Hong Kong, a train of tsunami waves was recorded shortly after midnight. The crest of the first
wave arrived around 00:10 on 27 December, with an amplitude of about 11 cm crest-to-trough. The
wave recurred with lesser amplitudes at intervals of about 10 to 20 minutes for 2 to 3 hours. A postanalysis
using a numerical tsunami model based on high resolution bathymetry and tropography
predicted an arrival time and amplitude commensurate with the tidal records. The event provided useful
data for verification of the numerical model which could be used to support future tsunami forecasting
in Hong Kong.
Keywords: tsunami, luzon strait, numerical model