The document discusses five main earthquake hazards: ground shaking, liquefaction, landslides, ground rupture, and tsunamis, highlighting their definitions, causes, and impacts. Understanding these hazards is essential for safety and preparedness, emphasizing the need for effective mitigation strategies and public education. Key recommendations include emergency preparedness, structural reinforcement, and being aware of warning signs to enhance safety during seismic events.

2. Earthquake
Hazards: Unveiling
Nature's Powerful
Forces
Introduction to Earthquake
Hazards

3. Introduction to Earthquake Hazards
● Earthquakes are natural
phenomena that can cause
significant damage
● Understanding earthquake
hazards is crucial for safety and
preparedness
● This presentation will explore five
main earthquake hazards
● We'll focus on how underwater
earthquakes generate tsunamis

4. What Are Earthquake Hazards?
Earthquake hazards are the various dangers and risks associated with
seismic events. The five main hazards we'll discuss are:
● Ground shaking
● Liquefaction
● Landslides
● Ground rupture
● Tsunamis

5. Hazard 1: Ground Shaking
● Definition: The vibration of the Earth's surface during an earthquake
● Primary cause of earthquake damage
● Intensity varies based on:
● Earthquake magnitude
● Distance from the epicenter
● Local geology

6. Effects of Ground Shaking
● Building damage or collapse
● Disruption of utilities (water, electricity, gas)
● Falling objects and debris
● Road and bridge damage
● Emotional distress and panic

9. Hazard 2: Liquefaction
● Definition: When water-saturated
soil loses strength and behaves
like a liquid
● Occurs in loose, granular soils
with high water content
● Can cause buildings to sink or tilt
● May result in sand boils or mud
volcanoes

10. Consequences of Liquefaction
● Structural damage to buildings and infrastructure
● Buoyancy of underground tanks and pipes
● Lateral spreading of the ground
● Formation of sand boils and mud volcanoes
● Increased risk in coastal and riverside areas

11. Hazard 3: Landslides
● Definition: The movement of rock,
soil, or debris down a slope
● Can be triggered by ground shaking
or soil saturation
● Types include:
● Rock falls
● Debris flows
● Slumps

12. Landslide Dangers
● Burying or crushing structures
and people
● Blocking roads and evacuation
routes
● Damming rivers, potentially
causing floods
● Triggering additional landslides
● Long-term landscape changes

13. Hazard 4: Ground Rupture
● Definition: The physical breaking and displacement of the ground surface
● Occurs along fault lines
● Can cause severe damage to structures built directly on the fault
● May lead to permanent changes in the landscape

14. Impact of Ground Rupture
● Splitting of roads, buildings, and infrastructure
● Creation of scarps (small cliffs) in the landscape
● Offset of streams and other natural features
● Long-term changes to local topography
● Potential for ongoing fault creep

15. Hazard 5: Tsunamis
● Definition: A series of ocean waves caused by sudden water
displacement
● Often triggered by underwater earthquakes
● Can also be caused by landslides or volcanic eruptions
● Capable of traveling long distances across oceans

16. How Underwater Earthquakes Generate
Tsunamis
● Seafloor displacement: The earthquake causes a sudden uplift or drop in
the ocean floor
● Water column disturbance: This movement displaces a large volume of
water
● Wave formation: The displaced water forms a series of long waves
● Wave propagation: Waves travel outward in all directions from the source
● Coastal impact: As waves approach shore, they grow in height and lose
speed

17. Tsunami Wave Characteristics
● Long wavelength (up to 200 km
between wave crests)
● Low amplitude in deep water (often
less than 1 meter)
● High speed in deep water (up to 800
km/h)
● Increase in height as they approach
shore
● May appear as a rapid rise in water
level or a wall of water

18. Tsunami Warning Signs
● Strong ground shaking near the coast
● Unusual sea behavior (rapid recession or rise)
● Loud roaring sound from the ocean
● Official warnings from authorities
● Remember: If you see signs, move to higher ground immediately!

19. Tsunami Impacts
● Flooding of coastal areas
● Destruction of buildings and infrastructure
● Erosion of beaches and coastlines
● Loss of life and injuries
● Long-term economic and environmental damage

20. Earthquake Hazard Mitigation
● Building codes and structural reinforcement
● Land-use planning to avoid high-risk areas
● Early warning systems
● Public education and preparedness drills
● Emergency response planning

21. Preparing for Earthquake Hazards
● Create an emergency kit with supplies
● Develop a family communication plan
● Secure heavy furniture and objects
● Know evacuation routes and safe meeting places
● Stay informed about local hazards and warning systems

22. What to Do During an Earthquake
● Drop, Cover, and Hold On
● Stay away from windows and heavy objects
● If outdoors, move to an open area
● If in a vehicle, pull over safely
● Be prepared for aftershocks

23. Conclusion: Staying Safe in Earthquake
Country
● Understand the five main earthquake hazards
● Recognize the special danger of tsunamis from underwater earthquakes
● Stay informed and prepared
● Follow official guidance and warnings
● Remember: Knowledge and preparation save lives!

24. ESSENTIAL QUESTIONS
● How does the movement of tectonic plates contribute to the formation of
underwater earthquakes?
● What role does water displacement play in the generation of tsunamis
following an underwater earthquake?