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Question 1

Magnitude (Definition)

Answer 1

Magnitude refers to the strength or intensity of a hazard. For ecological hazards, it’s measured by the number of recorded cases, deaths, and disability-adjusted life years (DALYs).

Question 2

Magnitude (Ebola Case Study)

Answer 2

The 2014–16 Ebola outbreak had 28,643 cases and 11,323 deaths—11x larger than all other outbreaks combined. The average fatality rate was 39.5%, with Guinea’s rate at 65%.

Question 3

Duration (Definition)

Answer 3

Duration is how long a hazard lasts, including time to recover and bring it under control. For disease, it also includes recovery time and long-term health impacts.

Question 4

Duration (Ebola Case Study)

Answer 4

The 2014–16 outbreak lasted over 2 years (Jan 2014 – Jun 2016). Symptoms develop in 2–21 days, but long-term effects (joint pain, neurological issues) can last a lifetime.

Question 5

Frequency (Definition)

Answer 5

Frequency is how often a hazard occurs in a given area or globally.

Question 6

Frequency (Ebola Case Study)

Answer 6

Ebola has occurred in West Africa roughly every 5 years since 1994. Zoonotic disease outbreaks are rising—60% of human infectious diseases originate from animals.

Question 7

Probability (Definition)

Answer 7

Probability refers to the likelihood of a hazard occurring in a specific region.

Question 8

Probability (Ebola Case Study)

Answer 8

Ebola has a high regional recurrence rate, but only a 3% chance of a major (>1000 deaths) outbreak. Zoonotic diseases have increased likelihood due to animal-to-human transmission.

Question 9

Scale of Spatial Impact (Definition)

Answer 9

Describes the area affected by a hazard—local, regional, or global.

Question 10

Scale of Spatial Impact (Ebola Case Study)

Answer 10

Ebola spread to 8+ West African countries. All districts in Sierra Leone and Liberia, and 27/34 in Guinea, were affected. The disease reached cities for the first time, increasing transmission risk.