Transcript Indian Ocean Earthquake - School District 67 Okanagan Skaha

Indian Ocean Earthquake
Dec. 26, 2004
Earthquake
• As many of us were sitting down to
Christmas dinner (4:58 p.m. Dec. 25th
Victoria time) the largest earthquake in 40
years the hit the Indian Ocean
• At 7:58 a.m. local time on Dec. 26, 2004 a
magnitude 9.3 earthquake occurred off the
coast of Indonesia (initially measured as
9.0)
• The focus was 30 km below the ocean floor
Although the earthquake’s epicentre was in
the Indian Ocean, the region is in the edge of
the “Ring of Fire”
Location of Epicentre in Indian
Ocean
• The earthquake set off a series of
aftershocks as the plate boundary continued
to shift.
• At least 15 aftershocks between magnitudes
5.8 and 7.3 happened in the next 12 hours
• Aftershocks continued for months as the
plates settled into their new positions
• From this info, scientists have estimated
that the rupture zone was over 1200 km
long and up to 100 km wide, with most of
the movement in the southernmost 400 km
of that zone
• At the focus, it is estimated that the plates
moved about 20 m
• The ocean floor moved about 10 m WSW
and was uplifted several metres
Tectonic
Plates and
Aftershocks
1 Month of
Aftershocks
Epicentre
Epicentre
Previous Earthquakes
Earthquakes in area
since 1900
Previous Tsunamis
Previous Tsunamis
in Area
• Within hours tsunamis had hit coastal areas
around the Indian Ocean as far away as
4500 km from the epicentre
• Within the next few days, the enormity of
the disaster grew as more information came
in from areas hit
Countries Affected
Hours after Earthquake
Time for Tsunami Indian Ocean
Animation
(5 hours)
Local
Animation
Full Indian
Ocean
Animation
• This horror is ongoing for those in the path
of the devastation as over 1 million people
are left homeless, surrounded by death and
destructions without safe drinking water,
food or sanitation
• The death toll has surpassed 200,000 people
and could reach 300,000 as more bodies are
found.
• Humanitarian aid poured into the area to help
rebuild and stop the spread of disease which
could sweep these areas
Before &
after of a
village in
Aceh,
Sumatra
Indonesia
Before & After Images from
Indonesia
• View Images
March 28, 2005
• Another large earthquake (magnitude 8.7)
hit off the coast of Sumatra (approx 300 km
south east of the December quake)
March 28, 2005
How far inland could a tsunami travel?
Not only is the wave large,
but the land itself can drop as
a result of the earthquake
This is called subsidence
It Could Happen Here
• The boundary of the Juan de Fuca and
Pacific Plate (called the Cascadia
Subduction Zone) is a similar type of
boundary
• Historical records indicate that a similar
“megathrust”earthquake of magnitude 9
happened here in the year 1700