Geomorphology studies why landscapes look the way they do, their forming history and dynamics as well as try to predict future changes, with focus on what happens on the surface and above it. In order to understand the concept of disaster, we should understand some of frequently basic terms such as hazard, exposure, vulnerability, capacity, risk and disaster and how its definition might change according to the context it happen in, as different countries look at hazards and calamities differently. Hazard is defined as a dangerous phenomenon, substance, human activity or condition that may cause loss of life, injury or other health impacts, property damage, loss of livelihood & services, social & economic disruption or environmental damage. Hazard is a potentially damaging phenomenon that could be caused by natural or human-induced. Some of the examples of hazard are typhoon, extreme rains, earthquake, tsunami, severe flooding, rain-caused landslide, and rough seas. Exposure is the degree to which the elements at risk are likely to experience hazard events of different magnitude. Vulnerability is the characteristics of a community, system or asset that make it susceptible to the damaging effects of a hazard. This may arise from various physical, social, economic & environmental factors. Vulnerability comprises of three components such as: (1) social integration; (2) physical vulnerability; (3) psychological. Capacity is the combination of all strengths and resources available within the community, society or organization that can reduce the level of risk or effects of a disaster. Risk is the combination of probability of an event to happen and its negative consequences, while disaster is a natural or man-made hazard resulting in an event of substantial extent causing significant physical damage or destruction, loss of life, or drastic change to the environment.
Disasters are generated by the greater exposure to natural and human-induced hazards, climate change and variability. Surprisingly, a list of numerous types of manmade such as floods, earthquakes and landslides in the tropics occur with the highest frequency. Human occupied land, whereas some of them are prone areas towards natural disasters. Human intervention to environment has been ages; the level of impact is varied, local to global. Almost all disasters occur in tropical areas occur due to some specific aspects such as geological, geomorphological, climatological, hydro-meteorological, and biological components. Different preparedness and mitigation measures has been developed due to differences Disaster Risk Reduction (DRR) policies in each country and the efforts of different organization vary to the hazard present in the area. Landscape approach, in geomorphological perspectives, was used in the assessment of certain hazard. It covers not just one area but the areas parallel to it as it may also be affected by a certain hazard.
Flooding, as an example, an area surrounded by a river, that is susceptible for flooding. In this case, the downstream are the mostly affected by the hazard as it serves as the catch basin. In costal watershed management, downstream area is likely more developed than the upstream area. The urbanization of the area increases the risk to the hazards because based on the general research outcome, it increase heat, less evapotranspiration, less precipitation, increase temperature, sea level rise, land subsidence, global warming that makes the environment vulnerable. However, the intervention on the downstream may not be that effective if the upstream area does not take any action towards it. Community who live in the certain location may know the situation, however, with the increasing urbanization and/or development, these people gives focus on their economic growth. This makes the people more vulnerable to hazards. In the same manner the Integrated Risk Management (IRM) works, where the Disaster Risk Reduction, Climate Change Adaptation and Ecosystem Management and Restoration are being integrated. Interventions as such also provide sufficient economic productivities: intercropping, tree growing, multi stratum of vegetation which protects soil surface from erosive rainfall and runoff.
The lecture of Prof Sunil can be downloaded on the following link: Disaster risk Management on Tropics: Geomorphological Perspective