The Hengchun earthquake doublet off southern Taiwan
Two earthquakes struck in the Luzon Strait off Hengchun at the southern tip of Taiwan, eight minutes apart: the first at 12:26 UTC at magnitude about 7.0, the second at 12:34 UTC at about 6.9, at focal depths of the order of 44 and 50 km. They were the largest events recorded in south-western Taiwan in a century. A small tsunami was recorded on nearby tide gauges. The seismic damage on land was comparatively limited; what made the event globally significant happened on the seabed, where the shaking set submarine landslides and sediment density flows moving down the canyon system toward the Manila Trench.
Historical — it happened, and the record is settled.
Subjects
- The Luzon Strait · maritime region · Western Pacific
- The turbidity current · natural phenomenon · not located
Evidence
Partly verified — Core facts are sourced; some optional detail is deliberately absent. This is the standing of the weakest source, not an average.
Source mechanisms and rupture processes of the 26 December 2006 Pingtung earthquake doublet
Supports the timing, magnitudes and focal depths used here: a first event at 12:26:21 UTC on 26 December 2006 at about magnitude 7.0 and a second at 12:34:15 UTC at about 6.9, at focal depths of roughly 44 and 50 km, with a small recorded tsunami. V55 verification basis: NOT read; the parameters were carried by retrieved search results attributing them to the Central Weather Bureau catalogue as reported in that literature. Reported magnitudes for these events vary between catalogues, which is normal and is why approximate values are used here.
Terrestrial, Atmospheric and Oceanic Sciences and associated Academia Sinica special issue material · 2008 · Partly verified
Special issue literature on the 2006 Pingtung earthquake doublet, Terrestrial Atmospheric and Oceanic Sciences and the Academia Sinica earthquake data centre; with the Central Weather Bureau catalogue parameters as reported therein
Insights into Submarine Geohazards from Breaks in Subsea Telecommunication Cables
Supports the account of the 2006 Luzon Strait cable failures as a sequential process driven by earthquake-triggered sediment density flows running down submarine canyons into the Manila Trench, with flow speeds of several metres per second inferred from break timings. V55 verification basis: NOT read; retrieved in summary only. Published break counts for the 2006 event differ between analyses — eight, nine, eleven, thirteen and twenty-two all appear — and this pack states the range rather than adopting one.
Oceanography (The Oceanography Society) · Partly verified
Insights into Submarine Geohazards from Breaks in Subsea Telecommunication Cables, Oceanography, tos.org; with the associated literature on the 2006 Pingtung earthquake doublet and the resulting sediment density flows
Recorded on The Luzon Strait
Related
Related because they share a subject in the Atlas — never because the text looks similar.
- Four cables fail off Côte d'Ivoire and thirteen countries lose connectivity · 2024-03-14
- Cables in the Luzon Strait break in sequence over nine hours · 2006-12-26 – 2006-12-27
- East Asian connectivity degrades for weeks · 2006-12-26 – 2007-02
- The Grand Banks earthquake breaks cables in sequence · 1929-11-18