ERTH 2415 Lecture Notes - Lecture 1: Return Period, Natural Hazard, Water Cycle
10 Oct 2016
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Document Summary
Natural disaster: an extreme natural event in which a large amount of energy is released in a short time with catastrophic consequences for life and infrastructure in the vicinity. Natural hazard: a source of danger that exists in the environment and that has the potential to cause harm. Unstable snow and rock on mountain slope. Vulnerability: likelihood that a community will suffer, both in terms of fatalities and physical damage, when exposed to hazards in the environment. Number of similar events per unit time. On average, 4 former tropical cyclones affect atlantic canada every year: frequency = 4 occurrences per year. Severe hurricanes strike the us on average every 6 years. This does not mean that there is a severe hurricane exactly every 6 years! Magnitude: amount of energy fueling a natural event. Amplitude of ground motion during an earthquake. Low magnitude events occur frequently (have a short return period) High magnitude events are rare (have a long return period)
