![Picture](/uploads/1/4/6/4/14649916/1271687_orig.jpg)
How are they caused? What are the effects?
The earths crust is very brittle, so when rocks near the surface are put under pressure, they break. When these rocks perform such movement, an earthquake occurs sending a pattern of vibrations into the earth, also known as seismic waves. The pattern of seismic waves moves out from the place where the rock breaks, like the same way the water ripples out when a pebble is dropped into a pond. These seismic waves are strong enough to damage roads, bridges and cities.
The Australian continent does not lie on the edges of the tectonic plates, however this does not mean that Australia is free from earthquakes. The continental drift is continuously squeezing and stretching the rocks that lie deep below Australia. Huge faults open up in the ground where earthquakes are likely to strike. These earthquakes may not be as serious or as frequent as the ones that occur on the tectonic plates, however they are dangerous because they are not anticipated.
Earthquakes have enough power to:
Most of the world's earthquakes occur at the place where the tectonic plates meet. This means that the countries located right near the tectonic plates such as New Zealand, Japan, the west coast of North and South America and Papua New Guinea are in quite a dangerous position.
"80% of the world's worst earthquakes occur around the edge of the Pacific Plate." - Australian Geographic
Key terms relating to Earthquakes:
The earths crust is very brittle, so when rocks near the surface are put under pressure, they break. When these rocks perform such movement, an earthquake occurs sending a pattern of vibrations into the earth, also known as seismic waves. The pattern of seismic waves moves out from the place where the rock breaks, like the same way the water ripples out when a pebble is dropped into a pond. These seismic waves are strong enough to damage roads, bridges and cities.
The Australian continent does not lie on the edges of the tectonic plates, however this does not mean that Australia is free from earthquakes. The continental drift is continuously squeezing and stretching the rocks that lie deep below Australia. Huge faults open up in the ground where earthquakes are likely to strike. These earthquakes may not be as serious or as frequent as the ones that occur on the tectonic plates, however they are dangerous because they are not anticipated.
Earthquakes have enough power to:
- Cause building structures to collapse due to the intense shaking that occurs.
- They are often the offset to Tsunami's as they are the cause to a sudden vertical offset in the ocean floor. This is the beginning of this natural disaster.
- Large landslides can be triggered by earthquakes as the seismic waves vibrate putting the unstable mountains and hills into a vulnerable position.
Most of the world's earthquakes occur at the place where the tectonic plates meet. This means that the countries located right near the tectonic plates such as New Zealand, Japan, the west coast of North and South America and Papua New Guinea are in quite a dangerous position.
"80% of the world's worst earthquakes occur around the edge of the Pacific Plate." - Australian Geographic
Key terms relating to Earthquakes:
- Focus or Hypocentre: the point in the earth where an earthquake rupture starts.
- Epicentre: the position on the ground surface directly above the focus or hypocentre where a seismic rupture begins.
- Fracture, Zone or Fault: The line along which the break occurs.