Living with Tectonic Hazards KQ1 - Why Are Some Areas More Prone to Tectonic Hazards?

A natural hazard is a naturally occurring event that threatens human lives and cause damage (i.e. properties, infrastructure etc...).

Natural hazards can be tectonic or climate-related.

Tectonic

• Earthquakes                       
• Volcanic Eruptions
• Tsunami

Climate

• Droughts
• Floods
• Tropical Cyclones

Tectonic hazards are caused by plate movements when continental crusts and ocean floors move.  

Watch this video "Plate Tectonics Explained"

To better understand why tectonic hazards occur, let's look at the processes in the internal structure of the earth,

The crust which is the outermost layer of the earth, is broken into tectonic plates which move in relation to each other. These tectonic plates are part of the lithosphere, which includes the crust and uppermost mantle. 

It can be made up of oceanic crust, continental crust or a combination of both.

The earth's tectonic plates are constantly moving. The forces that work together and cause plate movements are

• Convection currents
• Slab-pull force

The figure below shows the different tectonic plate boundaries in the world. Majority of tectonic hazards occur at the edges or at the boundaries of these plates. The tectonic plates there move in different directions and at different speeds.


Types of Plate Movements

• Divergent (where plates move away from each other)
• Convergent (where plates move towards each other and the denser plate subducts under the plate that is less dense)  
• Transform (where plates slides past each other) 

So why are some areas more prone to tectonic hazards?

Some areas are more prone to tectonic hazards as they are located near to or at the edge of the plate boundaries. As the tectonic plates are constantly moving, they either collide or move away from each other, causing a release of energy and triggering tectonic phenomenon such as earthquakes, tsunamis and volcanic eruptions.

We will take a look at some of these phenomena in the next post!