2. Earthquake
Earthquake, any sudden shaking of the ground
caused by the passage of seismic waves
through Earth’s rocks. Seismic waves are
produced when some form of energy stored in
Earth’s crust is suddenly released, usually
when masses of rock straining against one
another suddenly fracture and “slip.”
3. Earthquakes
• Causes - tectonics or faults
• Magnitude - energy and intensity
• Seismic hazards - shaking, etc.
• Recurrence - frequency and regularity
• Prediction?
• Mitigation and preparedness
4. Causes
• Earthquakes are mainly caused by the
movement of faults or tectonic
plates.
• Landslides
• Nuclear Testing
• Volcanic Activities
10. The Richter scale
It is introduced by Charles Richter.
The Richter scale is used to measure the magnitude
of earthquake. Richter Scales contain mostly 0-9
scales.
Usually, Seismometer is used to measure the
magnitude of earthquake.
19. Liquefaction and the urban fire hazard:
San Francisco, 1906
2-6 m of lateral
displacement in old
marsh soils -> 300
breaks in water lines
City lost 90% of water
supply; fires raged out
of control
Photos: Archives, Museum of San Francisco
20. Ground motion, structural damage and basin
morphology: Mexico City, 1985
periodic periodic
random
bodysurface surface/body
Damage
heavy light heavy
ridge
basin basin
21. “Much of the building is
done by people putting up
their own houses. But they
cannot afford proper
materials and do not use
skilled labour. There are
many small kilns producing
bricks but because of
demand these are not fired
for the 28 days needed to
make them strong.”
Mohsen Aboutorabi,
Professor of Architecture,
(BBC News, 2003/12/30,
discussing the Bam earthquake in
which ~40,000 died)
Muzaffarabad,
Pakistan
(October 8, 2005
M 7.7; depth 10km)
23. Mitigation and preparation
• Don’t panic
• Stay inside (if inside) or outside (if outside)
• Hide under table or desk
• Lie down
• Don’t fire
• Slowly and carefully move outside the building
