Transcript Earthquakes - Cal State LA

China Earthquakes
Tangshan, 1976
Overview

Earthquake in China
 Tectonic overview
- Causes of
Earthquakes
– Damage
– Recovery
China Tangshan Earthquake
July 28th, 1976
 Time: 3:42 AM local
 Magnitude: 7.8
 Location: Under the
city Tangshan,
China. East of
Beijing.
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Causes of Earthquake China
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Earthquake occurred on
the fault TanchengLujiang (Tan-Lu) a fault
zone, or collection of
parallel faults.
China is being
squeezed as the Indian
plate (India) that moves
northeastward and the
Eurasian plate (Asia)
squeezing it from the
west.
Damage China
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Damages was caused
directly by the shaking of the
quake.
The fault ruptured at a depth
of 11 km (7 mi)
Fatalities: 242,419
Majority of Destruction was
in Tangshan city. The fact
that it was in the middle of
the night when most people
were sleeping.
Building codes were lenient.
After shock 16 hours later
measuring above M 7.0.
Recovery
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Rescue efforts were complicated by
the time of the event.
 Lack of power throughout the city.
 Poor building codes led to many
deaths.
 Many were rescued but not until
hours or days later.
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1. Government established prediction as a goal in
1966
– a. Especially valuable goal since many buildings are unsafe
– b. widespread involvement of people
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2. The Feb. 4, 1975 Haicheng quake was
predicted
– a. 7.3M with widespread damage
– b. Great reduction in loss of life
– c. Changes in physical parameters
• (1) Rapid rise in elevation and ground tilt
• (2) Fluctuation in Earth's magnetic field
• (3) Foreshocks
• (4) Groundwater fluctuations
• (5) Erratic animal behavior
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3. Notable failures
– a. July 27, 1976 Tangshan quake - no prediction
• (1) >650,000 dead and about 780,000 injured
– b. May 29, 1976 west Yunnan Earthquake 6.9M
– c. False predictions
• (1) Kwangtung - August, 1976
Papua New Guinea
July 17th , 1998
 Time: 6:49 PM local
 Magnitude: 7.1 RS
 Location: 20 KM off
the North Central
Coast of New
Guinea (So. Pacific
Ocean)
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Causes of Earthquake PNG
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Arc-continent collision
of the Pacific and Indian
Australian plate
boundary. North
Bismark and Pacific
Plates are colliding
beneath the IndiaAustralia Plate Margin.
Converging 70mm per
year with a lateral shear
between plates of 100
mm per year.
Damage PNG
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Damage was caused
indirectly by submarine
landslide triggered by
the shaking. (Tsunami 7
to 15 meters height, 40
km coast line)
Fatalities: 3,000
estimated
Majority of destruction
was in coastal
communities. Those
whom died were mostly
children.
Recovery PNG
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Donations were made by the Red Cross,
United States, and other international
organizations.
 Monetary contributions and relief grants
that focus on rebuilding communities, and
mitigation activities that may help to reduce
the impact of similar events in the future.
1. www.geocities.com/CapeCanaveral/Lab/1029/Tsunami1998PNG.html
2. http://walrus.wr.usgs.gov/tsunami/high_res.html
3. http://walrus.wr.usgs.gov/tsunami/PNG.html#Background