Timeline of the 2004 Indian Ocean earthquake
All times are Coordinated Universal Time (UTC)
Sunday, 26th December, 2004
00:58:53 UTC
A large earthquake occurred in the Indian Ocean near Sumatra,
Indonesia, causing a large wave packet that started moving towards
northeast and southwest. (See 2004 Indian Ocean earthquake for
details of the earthquake.)
01:07 UTC
Resulting seismic signals received at the NOAA Pacific Tsunami
Warning Center (PTWC) from stations in Australia triggered an alarm
that alerted watchstanders.
01:10 UTC
PTWC issued a message to other observatories in the Pacific with
its preliminary earthquake parameters.
01:14 UTC
PTWC issued a bulletin providing information on the earthquake and
stating there was no tsunami threat to the Pacific nations that
participate in the Tsunami Warning System in the Pacific (ITSU).
These member nations are part of the UNESCO Intergovernmental
Oceanographic Commission (IOC) and the International Coordination
Group for the Tsunami Warning System in the Pacific (ICG/ITSU).
India, Sri Lanka and the Maldives are not part of the Pacific
system.
01:23 UTC
A tsunami hits the coast in Indonesia. Banda Aceh, a town in
northwest Indonesia, receives tidal waves that are 9 meters in
height. Effects of the tsunami reach 4 kilometers inland from the
coastline. Just minutes prior to the tsunami, southeast Indonesia
had sustained damage from the earthquake.
02:04 UTC
PTWC issued a second bulletin revising the earthquake magnitude to
8.5. That bulletin stated no tsunami threat to the Pacific but
identified the possibility of a tsunami near the epicentre. No
additional information regarding the formation of a tsunami was
available. This first notification came 65 minutes after the
earthquake and 41 minutes after the wave first made landfall.
02:30 UTC
HST PTWC attempted to contact the Australia Met Service with no
luck but were successful in contacting Australia Emergency
Management. They confirmed they were aware of the earthquake.
02:33
A tsunami hit the coastal villages in Sri Lanka.
02:33 UTC
A tsunami hit the coasts in Thailand. According to many witnesses,
the first tidal wave hit the coasts in Phuket at 02:33 UTC. Khao
Lak was hit a few minutes later. A few tourists managed to receive
warning calls of big waves from other tourists in Phuket. According
to a lot of witnesses the tsunamis, 5-10 meters in height, came in
10 minute periods.
03:30 UTC
Internet newswire reports of casualties in Sri Lanka provided PTWC
with the first indications of the existence of a destructive
tsunami.
03:45 UTC
Armed with knowledge of a tsunami, PTWC contacted the US Pacific
Command (PACOM) in Hawaii.
03:45 UTC
PTWC received a call from a Sri Lankan Navy Commander inquiring
about the potential for further tsunami waves from
aftershocks.
04:00 UTC
U.S. Ambassador in Sri Lanka called PTWC to set up a notification
system in case of big aftershock. He said they would contact the
Sri Lankan Prime Minister's office for such notifications.
Continuing news reports gave increasing and more widespread
casualties.
05:25 UTC
The first reading from the Australian National Tidal Centre gauge
at Cocos Island west of Australia gave a reading of 0.5m
crest-to-trough.
05:25 UTC
The Harvard University Seismology Department reported its
preliminary Centroid Moment Tensor solution that indicated a
magnitude of 8.9.
05:45 UTC
PTWC contacted the Australian Bureau of Meteorology and advised
them about the increased earthquake magnitude and the 0.5m reading
at Cocos Island, as well as the possibility of a destructive
tsunami impact on Australia's west coasts.
06:00 UTC
PTWC re-contacted PACOM to advise of increased earthquake magnitude
and potential for further tsunami impacts in the western Indian
Ocean.
06:15 UTC
Australia Bureau of Met called PTWC to advise they had issued an
alert to their west coast.
06:20 UTC
NOAA National Weather Service Pacific Region director contacted
PTWC to report PACOM said no tsunami was observed at Diego Garcia
in the Indian Ocean.
08:15 UTC
PTWC spoke with U.S. State Department Operations and advised them
about the potential threat to Madagascar and Africa. They set up a
conference call with the U.S. embassies at Madagascar and
Mauritius, and PTWC advised them of the situation.
15:36 UTC
PTWC issued a third Tsunami Information Bulletin for this event
informing the Pacific that small sea level fluctuations from the
Indian Ocean tsunami were being observed in the Pacific, probably
from energy that wrapped around south of Australia.
