3.1. Calculating Disaster Magnitude

So, also here is another chart you can see from 1950 to 2005, the number of events that flood is increasing, storm also are increasing, earthquake is almost the same as from 1950’s to 2005, you cannot see much huge differences but other disasters you can see they are increasing very prominently.

Between 1950 and 2005, there has been a noticeable increase in the number of flood and storm events, indicating that climate change or other factors could be contributing to more frequent disasters. In contrast, the incidence of earthquakes during the same period appears stable, showing no significant increase or decrease. This trend emphasizes the growing concern for flood-related risks compared to relatively unchanged earthquake risks.

Think of it like a sports team. If a team consistently wins more games each season, it signals their performance is improving. In the same way, floods and storms are becoming more frequent, showing a rising 'performance' of these disasters over the years.

So, we are talking about hazards that this landslide or this stone when it is exposed to heavy rainfall or earthquake, it can have some potentiality to cause human injury or loss or property damage.

Hazards like landslides and earthquakes can lead to significant human injuries, loss of life, and damage to property. Just because an event occurs doesn't mean it will always result in harm; rather, it has the potential to do so depending on circumstances such as location and intensity.

Consider a tree branch that can fall during a storm. It may be risky if it falls on a busy road or homes, but if it falls in an isolated area, it may cause little to no harm. In this way, the risk associated with hazards depends on where and how they occur.

Why, so that is important when we are talking about disaster risk management. When there is an landslide in Mumbai, landslide in Delhi we are concerned about but when there is an landslide in Himalaya, we are not concerned about this.

Disaster risk management involves assessing the importance of different hazards based on human exposure. Landslides in densely populated areas like Mumbai or Delhi attract concern because of their potential to impact many people. However, landslides in remote areas like the Himalayas may not invoke the same urgency since they are less likely to affect large populations.

Imagine a busy city street vs. a quiet rural road. If an accident happens on the busy street, it gets more attention and concern compared to the rural road, where fewer people are affected. This illustrates how location and population density influence our perception of risk.

So, this one we are calling as exposure; the situation of people, infrastructure, housing, production capacities and other tangible human assets located in hazard-prone areas.

Exposure refers to the presence of people, infrastructure, and assets in areas where hazards may occur. The more densely populated or built-up an area is, the higher its exposure and the greater the potential risk should a disaster strike. Understanding exposure is critical for assessing overall disaster risk.

Think of exposure like placing a toy in a room where a pet is known to cause chaos. The toy is 'exposed' to potential damage based on how prone the room is to being disturbed. In disaster terms, areas with more people and buildings are more 'chaotic' in the event of a hazard.

So when we are talking about exposure, maybe these are indicators, we can define how many, what extent, who are exposed. Let us say, building use; residential, commercial, industrial, they define that how many people, what extent, what type of people are exposed to disasters.

Exposure can be measured using various indicators, such as the type of buildings present—residential, commercial, or industrial. Each type of usage indicates different levels of risk and vulnerability among the people who occupy those spaces. For example, commercial buildings may house more people at work during business hours, increasing potential exposure compared to residential houses.

Imagine a bakery that is very busy during the day with customers. If there's a hazard during that time, more people are at risk. In contrast, if there were a hazard at night when the bakery is closed, fewer people would be exposed. This is how building use impacts exposure.

Like, if we have Kutcha houses and mud houses and you have concrete houses, it also wood houses, these also define that one extent, people will be impacted with these hazards.

The construction quality and type of buildings significantly influence how vulnerable people are to hazards. For instance, mud houses may be more susceptible to damage during severe storms compared to concrete structures. The risk of disasters is not only about how many people are exposed but also how resilient their homes and communities are to such events.

Think of a cardboard box left in the rain versus a plastic container. The cardboard (like a less sturdy house) will likely get damaged, while the plastic (like a more resilient house) will stay intact. This illustrates how building materials impact vulnerability and risk.

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