UCL Institute for Risk & Disaster Reduction
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Magnitude 9.0 (JMA scale) earthquake
Occurred at 02:46:23 pm local time near the east coast of Honshu, Japan
Subduction zone megathrust earthquake
Five minutes in duration,
It triggered a tsunami more than 10 m high
Figure 2 - Preliminary fault model from Geospatial Information Authority of Japan
Causing immense damage
alongobserved
the northeast
coast
of displacements
Japan
(GSI) showing
and calculated
GPS
from select
GEONET stations. See ! more
Coseismic slip model
It rupture crust 500 km
long by 200 km wide in
3 sub events.
t has been!It Itisisthe
very
largest known
mber of casualties and
event in and around
000, which is the worst
Japan
The Japanese Island also
shock. Seismicity became
e had a medium shock
Figure 3 - Preliminary highly smoothed model of coseismic slip for the 11 March
UCL Institute for Risk & Disaster Reduction
Was the 11th March 2011 Tohoku earthquake forecasted?
•  Earthquakes expected in the
source region had much
smaller magnitude M 7.4 to
8.2
•  From 6 smaller fault
segments based on historical
seismicity
•  The March 11 earthquake
ruptured all 6 segments in a
single earthquake.
UCL Institute for Risk & Disaster Reduction
Was the
11th
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March 2011 Tohoku earthquake forecasted?
•  Within 10 minutes of the first tsunami reached the
coast as minor backwash 10s cm high
•  30-40 mins after the earthquake huge 4-7 m high run
up attacked the coastal lowlands.
•  The Sanriku coast have suffered repeated tsunami in
1896, 1933 and 1960 (Chilean) earthquakes
•  In Iwate prefecture run-up heights exceeded 10m but
in Miyagi and Fukushima prefectures less than 4m
•  So nobody had expected such high tsunami
•  But tsunami in 869 and 1611 6-8m high had
devastated the Sendai plain
Koji Okumura, Hiroshima University
K/3
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UCL Institute for Risk & Disaster Reduction
Could the Tohoku earthquake be forecast?
Magnitude
– yes!
Ignore
coloured dots
Slip‐deficit
from
modelled
GPS
(Igarashi
2003
JGR).
Similar
to
the
slip
patch
last
Friday?
Earthquakes
aftershocks
(DART)warning
tsunami buoys
work.
Here are some good resources that will help you learn more about both
systems.
UCL Institute for Risk & Disaster Reduction
SXSW: Tablets will Become Ubiquitous when the Xoo
Becomes Obsolete
SXSW: How Smart Gadgets Let Us Down
Did the warning systems work?
Credit: Japan Meteorological Agency.
SXSW: Building Human Rights Into Social Sites
MOR
Yes – and
saved lives
This image shows the location of detected seismic activity, and its severity (Japan uses a
different scale for measuring the intensity of earthquakes). Further information here.
conference
gadgets
social networks
BLOG TOPI
game dynamics
SXSW
television
gaming
video gam
Credit: NOAA
The image above shows the location of tsunami buoys across the Pacific, and which buoys
have been triggered (the larger yellow diamonds). Live information can be found in this page
at the National Oceanic and Atmospheric Administrations National Data Buoy Center.
Updated 14:30 EST: NOAA has published a page dedicated to the tsunami event.
How Japan's Earthquake and Tsunami Warning Systems Work - Technology Review
22/03/2011 10:46
The graphic above shows how the Deep-ocean Assessment and Reporting of Tsunami
(DART) tsunami buoys work.
Credit: Japan Meteorological Agency
The graphic above shows the stages involved with triggered Japan's earthquake warning
system. Further information can be found at this page of the Japan Meteorological Agency.
http://www.technologyreview.com/blog/editors/26505/
Credit: NOAA
Credit: NOAA.
Credit: NOAA
The image above shows the location of tsunami buoys across the Pacific, and which buoys
The image above was generated using the method of splitting tsunami (MOST) model. It uses
data collected by tsunami buoys to estimate the wave arrival time and the wave height of the
tsunami.
FACEBO
UCL Institute for Risk & Disaster Reduction
Is this the Big One?
Great Kanto Earthquake 1923
No
JMA Intensities
UCL Institute for Risk & Disaster Reduction
Great Kanto Earthquake 1923
•  Great Kanto earthquake (Mw = 7.9; Ms = 8.2)
•  Occurred along the Sagami Trough in the
Sagami Bay on 1 September 1923
•  One of the most disastrous earthquakes in
Japanese history
Saiten Tamura
Refugees –
Imperial Palace
•  Earthquake claimed 99,331 dead,
43,746 missing, and left 3.4 million
homeless
•  Major social consequences systematic massacres & political
assassinations