Earthquakes are some of the most powerful natural disasters on earth and a single earthquake can cause billions in damage and cause extensive loss of life. But what are all the causes and effects of earthquakes? And how can you prepare for a large earthquake? Here we aim to show you all about earthquakes through information, facts, pictures, videos and illustrations.
Earthquake definition
A sudden violent shaking of the ground, typically causing great destruction, as a result of movements within the earth's crust or volcanic action.
Causes of earthquakes
Causes of earthquakes.
The earth's crust is cracked into pieces called tectonic plates. These plates move around. In some places they move apart form each other and in other places, they move together. These movements are felt on the surface and they vary in size. Most are too small to be felt by humans and are measured using a sensitive machine called a seismometer. Some earthquakes are large and can cause extensive damage to property and loss of life.
Earthquake preparedness
Being prepared for earthquakes involves having a plan for before, during and after an earthquake. During an earthquake, the most important advice is to stay calm. Do you think you ill stay calm in an earthquake?
Earthquake simulators
Earthquake simulators are a great way to prepare for the unexpected. This Earthquake simulator in Honjo Bosaikan, Tokyo shows a Level Seven earthquake on the Japanese earthquake scale.
Richter Scale
The Richter scale measures the energy released
in an earthquake. The Richter scale is a logarithmic
scale with each point on the scale being ten times
larger than the point before. For example, a 5.0
earthquake is ten times larger than a 4.0 earthquake.
Size Frequency Description
< 2.0 several million a year Microquakes - only measured by machines
2.0 - 2.9 over 1,000,000 per year Felt by people lying down, no damage
3.0 - 3.9 over 100,000 per year Felt by people seated, rarely causes damage,
4.0 - 4.9 10,000 - 15,000 per year Minimal damage, some objects move, some shaking visible
5.0 - 5.9 1000 - 1500 per year Felt by everyone, slight damage to property
6.0 - 6.9 100 - 150 per year Earthquake proof buildings suffer slight to moderate damage
7.0 - 7.9 10 - 20 per year Damages most buildings, felt up to 250 km away from source
8.0 - 8.9 1 per year Major damage to buildings, damage over extensive area
9.0 + 1 every 10 - 50 years Damage extends over wide area, loss of life likely
Measuring earthquakes
Mercalli Scale
The Mercalli Scale is a descriptive scale that matches
the effects of an earthquake to a numeric level.
Size Description
I Not felt V Moderate IX Violent
II Weak VI Strong X Extreme
III Weak VII Very strong XI Extreme
IV Light VIII Severe XII Extreme
WHAT IS AN EARTHQUAKE?
