1.1. Hazards X Exposure X Vulnerability

Hello everyone, we are talking about lecture course on disaster recovery and build back better. I am Subhajyoti Samaddar, from Disaster Prevention Research Institute(DPRI), Kyoto University. In this lecture, we will talk about disaster risk considering 3 components; one is hazard, exposure, and vulnerability. so, we will give some small examples; illustrations with some theoretical ideas to define the very core aspect of disaster risk.

In this introduction, the speaker emphasizes that the core focus of the lecture is on understanding disaster risk. He introduces the three primary components that contribute to disaster risk: hazard, exposure, and vulnerability. Each of these components plays a critical role in defining how risks are assessed and managed in disaster contexts. The speaker also mentions that examples and illustrations will be provided to clarify these concepts, making them easier to understand.

Consider a city that is prone to earthquakes. The building structures represent the 'hazard' because they can be damaged during an earthquake. 'Exposure' refers to the people living or working in these buildings, as they are the ones at risk. Lastly, 'vulnerability' reflects how well these buildings can withstand earthquakes; older buildings might be more vulnerable than newer, fortified ones.

Let us imagine that this is a place near Roorkee in Uttarakhand; it could be a tourist spot, people coming here watching this mystic stone in a mountain well now, considering this slide is it risky? Does it look like that this could be fatal for the people, should you consider this is as disaster or disaster risk? Now, how about that if there is one individual is there; working there on the foothills, should you consider it more risky than the before one?

This chunk invites the audience to visualize a scenario in Uttarakhand. It prompts questions about the risk associated with natural hazards, such as a falling stone from a mountain. The focus is on understanding the context of risk based on the presence of individuals. If there is no one present, the risk is lower, but with one person working nearby, the risk significantly increases. This demonstrates how exposure can elevate disaster risk, even with the same hazard.

Imagine a cliffside tourist attraction. If no visitors are around, a rock falling might not be a big concern. However, if a tourist is sitting directly below the cliff, the risk of injury or disaster unfolds dramatically. This scenario illustrates how exposure to hazards can change the level of perceived risk.

Now, look at the next slide, so if there is a rain then, there is a possibility that this stone would hit this person so yes, we consider this is as risky. But if it is like that maybe in a mountain when there is no human being and this stone falling down on a forest, do you consider it as risky; a disaster?

In this segment, the speaker elaborates on the relationship between hazard and potential consequences. The presence of rain introduces the possibility of a stone falling and hitting a person, thus heightening risk. The speaker then contrasts this with a scenario in which the stone falls into a forest, highlighting that the absence of human exposure reduces the perceived risk of disaster. This illustrates that disaster risk is not merely about hazards but also intricately linked to human exposure.

Think of a scenario where road work is happening on a mountain. If it rains, loose stones can fall and endanger workers nearby. On the other hand, if those stones only fall in a remote forest, while it might be dangerous to wildlife, it isn’t a ‘disaster’ in a human context. This shows how the same event poses different risks based on human presence.

If we have avalanches, landslides in Himalayas, do we consider these events as disasters? But maybe if it is not in a remote mountain but people are living there, settlements are there compared to that top one, if we consider the bottom one to us, it is more risky than the top one.

This chunk connects specific types of natural hazards, such as avalanches and landslides, to their potential impact on human settlements. The key point is that an event which might be benign in a remote area becomes a disaster when it occurs where people live. The increase in human exposure ties directly to an increase in risk assessment, emphasizing that the context of the event matters significantly.

Picture a village nestled in the foothills of the Himalayas. An avalanche that rolls down the mountainside in a remote area might be just a natural occurrence, but if it reaches the village and endangers homes and lives, it transforms into a disaster. This illustrates how the same hazard can lead to dramatically different outcomes based purely on human exposure.

Maybe, we are more concerned, when there are more settlements are there. If this is happening; this landslide at night time. And if this landslide is happening at day time, we have different concerns and different way of measuring risk.

In this segment, the focus shifts to the timing of a hazard's occurrence, specifically a landslide. The speaker suggests that risks can be heightened at night when people are asleep compared to daytime when individuals are likely to be active. This introduces the concept of temporal vulnerability, where the risk associated with a hazard can vary significantly based on the time when it happens.

Consider a neighborhood prone to landslides. A landslide occurring during the day might catch people’s attention, allowing them to evacuate or move to safety. Conversely, if the landslide happens at night while most residents are asleep, the chance for injuries or fatalities greatly increases due to vulnerability being highest when people are least aware or prepared.

But if this same thing is happening in an urban place in a city area what happens?

The discussion concludes by shifting focus to urban areas. The implication is that urban settings, with their dense population and infrastructure, could exacerbate the effects of natural hazards like landslides or other disasters. The proximity of people and structures leads to a heightened awareness and potential for disaster, further emphasizing the need for understanding risk in diverse contexts.

Think of a city built on the outskirts of a mountain range. If a landslide were to happen there, numerous lives could be at risk all at once compared to a remote area. It’s as if the same event suddenly becomes more dangerous simply because many people are present and vulnerable in close proximity.

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