Earthquake Hazards
Introduction
Earthquakes are natural disasters that occur when there is a sudden movement of
rocks in the Earth’s crust, often along fault lines. These movements release energy
in the form of seismic waves, causing the ground to shake. Earthquakes can lead to
various hazards that pose risks to people, property, and the environment.
Understanding these hazards and preparing for them can help reduce their impact.
Let’s explore the potential earthquake hazards, their effects, and how to prepare for
them.
Potential Earthquake Hazards
1. Ground Shaking
o Definition: Ground shaking is the vibration of the Earth's surface
caused by seismic waves during an earthquake. It is the most common
and widespread effect of earthquakes.
o Example: During the 1994 Northridge earthquake in California, strong
ground shaking damaged buildings, bridges, and roads.
o Impact:
Weakens and collapses buildings.
Causes objects to fall, leading to injuries.
o Precautions:
Build earthquake-resistant structures.
Secure heavy furniture and appliances to walls.
Drop, cover, and hold on during an earthquake.
2. Ground Rupture
o Definition: Ground rupture occurs when the Earth's surface breaks
along a fault line during an earthquake.
o Example: The 1999 İzmit earthquake in Turkey caused visible ground
ruptures that displaced roads and pipelines.
o Impact:
Destroys roads, railways, and buildings directly above the fault.
Creates cracks or offsets in the ground.
o Precautions: Avoid constructing buildings and infrastructure directly
on fault lines.
3. Liquefaction
o Definition: Liquefaction happens when loose, water-saturated soil
behaves like a liquid due to strong shaking.
o Example: In the 2011 Christchurch earthquake in New Zealand,
liquefaction caused widespread damage to buildings and roads.
o Impact:
Buildings and infrastructure sink, tilt, or collapse.
Roads and pipelines may be severely damaged.
o Precautions:
Avoid building on loose, water-saturated soil.
Use soil improvement techniques to stabilize the ground.
4. Earthquake-Induced Ground Subsidence
o Definition: Ground subsidence refers to the sinking or settling of the
ground surface due to an earthquake.
o Example: The 2011 Tohoku earthquake in Japan caused subsidence in
coastal areas, making them more prone to flooding.
o Impact:
Changes land elevation, leading to increased flood risk.
Damages infrastructure such as buildings and drainage systems.
o Precautions: Avoid constructing in areas with a history of subsidence
and enhance drainage systems.
5. Tsunami
o Definition: A tsunami is a series of large sea waves caused by
underwater earthquakes, landslides, or volcanic eruptions.
o Example: The 2004 Indian Ocean tsunami, triggered by a massive
earthquake, caused widespread destruction in coastal areas across
multiple countries.
o Impact:
Destroys coastal communities and infrastructure.
Causes loss of life and displacement.
o Natural Signs of a Tsunami:
A strong earthquake near the coast.
Unusual changes in sea level, such as rapid receding of water.
A loud roar from the sea.
o Precautions:
Move to higher ground immediately after feeling a strong
earthquake near the coast.
Follow tsunami evacuation routes and warning systems.
6. Earthquake-Induced Landslides
o Definition: Landslides occur when the shaking from an earthquake
causes soil, rocks, and debris to slide down slopes.
o Example: The 2008 Sichuan earthquake in China triggered landslides
that buried villages and blocked rivers.
o Impact:
Destroys homes and infrastructure.
Blocks roads and rivers, leading to flooding.
o Precautions:
Avoid building near steep slopes or areas prone to landslides.
Stabilize slopes with vegetation or engineering techniques.
