3. Historical Perspective on Hazards

Now, coming another important feature is the speed of onset like, if we consider a flood, it is a flash flood, it is very sudden without warning, very quick or is it a kind of slow process like in case of cyclone, we have much time to predict so, we have; we can prepare ourselves, we have better early warning system and we can take time but in case of earthquake, we do not have any time, it is very sudden or in case of flash flood, we have less time.

The speed of onset of a hazard refers to how quickly an event occurs once it is triggered. For example, flash floods happen very suddenly and give little to no warning, while cyclones can be predicted in advance, allowing people to prepare. Earthquakes occur without warning, making them particularly dangerous because there is no time to react.

Think of it like a sprinter at a race. An earthquake is like the gunshot that starts the race—there's no time to prepare and it's instantaneous. A cyclone is more like a long-distance runner; you have time to watch them approach and prepare for their arrival.

Speed of onset is very important and when you are considering the hazards in disaster risk management and the spatial dispersion; area likely to be affected by particular event. And temporal spacing also very important; what time, when and it is happening, are they random, are they occurring in a cyclic process in a recurring process or they are one-time events, so these are important features when we are dealing with hazards.

When managing disaster risks, understanding where (spatial dispersion) and when (temporal spacing) hazards will occur is crucial. Spatial dispersion refers to the geographical areas that may be impacted by a disaster, while temporal spacing addresses the timing of these events. Some hazards might happen randomly, while others may follow predictable cycles, such as seasonal flooding.

Consider a schedule for classes. Just like knowing that math class is at 9 AM every Monday helps you plan your week, understanding that hurricanes typically hit in certain months allows communities to prepare well in advance.

In case of just for an example, maybe we can see that in case of earthquake; earthquake occurs along the boundaries of the tectonic plates of the earth crust. this is one hazard and when this is the source of the hazards and when this happen and this happens, we can see that these plates come in contact with each other and the pressure builds up an earthquake occurs.

Earthquakes primarily occur at the boundaries of tectonic plates. When these plates move and collide, they can become stuck against each other due to friction. Over time, pressure builds up until it is released in the form of an earthquake as the plates suddenly move.

Imagine two cars stuck in a traffic jam pushing against each other. As they push, they build up tension until one sudden movement causes a crash (the earthquake) that changes the situation dramatically.

Now, this is just simply a physical event, this is you can see some of the distribution of the tectonic plates in some places and this hazard; this earthquake hazard, we have 3 processes; physical process that can trigger this hazard. One is that convergent boundaries; when two plates collide together this created the Himalayan mountain so, one way of the event of earthquake that can happen when two plates are colliding each other.

There are three main types of tectonic boundaries that can cause earthquakes: convergent boundaries, where two plates collide and can create mountain ranges like the Himalayas; subduction zones, where one plate slides beneath another; and divergent boundaries, where two plates move apart. Each of these interactions can release energy that causes earthquakes.

Think of convergent boundaries like two people trying to hug each other really tightly; they press against each other until one of them pushes back, resulting in a release of energy that can shake everything up around them.

Now when we are talking about hazards, can we avoid hazard? No, historically hazards were there, it is there and it will remain. So, we cannot avoid hazard basically.

Hazards are an inevitable part of our natural world and cannot be completely avoided. They have existed throughout history and will continue to occur. This understanding is crucial for effective disaster planning and risk management.

It's like knowing that storms will come during certain seasons. Instead of trying to stop the storms (which we cannot do), it is better to prepare for them, such as by building stronger homes or having emergency kits ready.

Now, looking into the disaster; number of disasters from 1980’s to 2005, you can look as I told also before, it is the flood that is the most reported disastrous event. 35% of all disasters from 1980 to 2005 are flood disasters. Another one is also big share is the wind storm, earthquake is only 11%, extreme temperature is 11%, so overall 90% of disasters are related to hydro-meteorological disasters.

Between 1980 and 2005, floods were the most common disasters, accounting for about 35% of all reported events. Wind storms and earthquakes made up a smaller portion, each at 11%. This highlights that a large majority of disasters are related to water and weather events, known as hydro-meteorological disasters.

Imagine a survey of all the birthday cakes at a party—most cakes are chocolate (floods), while a few are vanilla (earthquakes). Just like most disasters are linked to weather-related events, you find that a similar pattern exists when people celebrate their special days.

Also, when we are looking into the loss of human life from 1980 to 2005, we can see that nearly 70% of loss of life are related to hydro-meteorological factors. So, hydro-meteorological disasters are very critical, particularly when we are looking into developing countries or underdeveloped countries.

From 1980 to 2005, about 70% of deaths caused by disasters were due to hydro-meteorological events like floods and droughts, emphasizing the significance of these types of hazards, especially in developing countries where infrastructure may be less capable of handling such events.

Think of how a weak bridge might collapse under heavy rains. In developing countries, this lack of sturdy structures means that people are more vulnerable to dying during such natural events, just like the bridge’s weakness leads to failure.

Similarly, flood 9%, earthquake is only 14%, here is the regional distribution of natural disasters from 1980 to 2005. You can see that Asia is one of the biggest sources of disaster, it is one of the hotspots compared to any other region, when we are talking about disasters.

The statistics also show that Asia is one of the regions most affected by natural disasters from 1980 to 2005, highlighting the vulnerability of this area. Floods and droughts, in particular, account for a significant number of disasters across the continent.

Just like certain sports teams might be more successful based on their environment, some regions are more prone to disasters. Asia can be seen as a disaster hotspot due to its geography and climate, making it face higher risks.

Here is also you can see from 1991 to 2002, the growth of disasters. So, actually it is increasing in all continents particularly in Asia, so in the 1990s and 2002, you can see in Asia’s, these disasters are actually more and more reported and more and more human losses and property damage are reported.

Between 1991 and 2002, the number of disasters was increasing across all continents, particularly in Asia, indicating a worrying trend of more frequent disasters along with significant human and property losses.

Consider a garden that starts out with a few weeds. If you don't address them, they continue to grow and spread, eventually taking over significant parts of the garden. Similarly, ignoring the signs of increasing disasters can lead to more severe impacts over time.

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