Quiz 2

Question 1

Define the word “earthquake”

Answer 1

a violent shaking of the Earth’s crust that result from the sudden release of energy along a fault line (between plates) or from volcanic activity

Earthquakes are sudden movement of the earth caused by the abrupt release of strain that has accumulated over a long time

Question 2

Recognise the basic elements of plate tectonics

Answer 2

Crustal plates moving in relation to each other –> constantly moving, spreading and changing shape
Earthquakes concentrate near the boundaries of the tectonic plates - happen when 2 plates rubbing against each other move suddenly and release energy

Question 3

Difference between Richter scale and a Mercalli scale for measuring earthquake severity

Answer 3

Ritcher scale: measures the amount of energy released in an earthquake - used to measure earthquake severity. 10 levels - each level is 10 times stronger than the last.

Modified Mercalli Intensity Scale (MMI)L measures the amount of ground motions. 12 levels of severity. Better than Ritcher because it predicts more of the kind of impacts that will occur on the ground surface as the result of a quake.

Question 4

Secondary disasters from earthquakes

Answer 4

Fires and explosion
Dam failures and floods
release of toxic or radioactive materials
tsunamis
landslides

Question 5

Id human factors that contribute to the severity of impact from earthquakes

Answer 5

Structural factors: building design and materials, building codes, lands
Technological factors: pipelines and electrical lines, harzardous material storage facilities, nuclear power facility
artificial causes (collapse of underground mines etc.)

Question 6

List immediate and delayed health effects of earthquakes

Answer 6

Immediate impacts happen at the time of the earthquake or within minutes
- minor injuries, lacerations, crush injuries to head and chest, haemorrhage, suffocation, drowning burns

Delayed impacts take longer and may develop over hours, days, weeks or months following the actual earthquake
- dehydration, environmental exposure, crush syndrome, wound infection and sepsis, smoke and dust inhalation

Question 7

Id major public health consequences of earthquakes

Answer 7

Morbidity: worsening of existing chronic disease
Mortality: 75% of deaths are caused by structural collapse (trauma or crush), urban fires. Survival rates 36hours for entrappment

Number of deaths and severe injuries: many and public health concern for safety high. Everything else focal to widespread damage = loss of hygiene, sanitation, shelter etc.

Question 8

Id prevention and control measures that can be taken for earthquakes

Answer 8

Avoid construction in areas of high seismic risk
safer construction and building codes
planning and exercises
community education
search and rescue
rapid assessment of impact
timely and appropriate disaster response
surveillance for injuries and diseases
dissemination of pubic health information
dissemination of public health information
environmental health and control measures
follow up epidemiology

Question 9

list the 6 causes of tsunamis

Answer 9

1. earthquake underneath the ocean (95% of all tsunamis are caused by this)
2. avalanches from glaciers
3. eruption of a volcano
4. underwater landslide
5. asteroid from space hits the ocean (rare)
6. landslide from the coastline falls into the ocean

Question 10

list conditions that must be present for an earthquake to cause a tsunami

Answer 10

Strength of earthquake: grater the 7.0M
Depth of earthquake: less than 25km
Resulting seabed uplift
Depth of water: more likely in deeper water

Question 11

list 3 warning signs that a tsunami may be about to occur

Answer 11

Large earthquake
Receding ocean
unusual sounds
other unusual ocean activity

Question 12

id the characteristics of a tsunami

Answer 12

90-05% occur in the Pacific Ocean (ring of fire)
Travel 300-600mph (same speed as a jet)
Generally about 10-49ft in height, though can be larger
Waves can travel several miles inland once on shore
Can have devastating PH consequences
Successive waves at intervals of 10-45mins

Question 13

id major public health consequences of tsunamis

Answer 13

Mortality: drowning and trauma
Large number of deaths and severe injuries
Large numbers of displaced populations: shelter, food, water, electricity, personal goods, sanitation
High public concern for safety
Majority of deaths occur during the tsunami
Death exceeds injury

Question 14

define tsunami

Answer 14

a series of waves generated by a sudden, large displacement of deaths water

a tsunami is formed by the energy of an earthquake with an epicentre under the ocean floor

Question 15

Describe 2 categories of floods

Answer 15

Flash floods: rapid onset (rain/structural failure), brief duration, steep terrains, little or no warning
River floods: slow onset (prolonged period of heavy rain or snow melt), long duration, concave terrains, advance warning

Question 16

Id the factors that influence the severity of a flood

Answer 16

Topographical makeup
May be related to other disasters: hurricane storm surges, earthquake-related dam failures, landslides or volcanic eruptions
Natural factors: soil character, monsoons, El Nino
Human: urbanisation, deforestation, overgrazing, improper construction, inadequate safeguards

Question 17

Id major public health consequences of floods

Answer 17

Mortality: most deaths in flash floods, most deaths are due to drowning, deaths vary according to country - developing nations have much higher death rates
Morbidity: injuries, toxic substance release, mental health, chronic disease, mould/mildew, infectious disease, contaminated water

MORTALITY LOW DEVELOPED, HIGH DEVELOPING

Question 18

id key public health and safety issues following a flood

Answer 18

Water quality
food safety
clean up activity safety
sanitation and hygiene
pests and vectors: insects, rodents, wild animals
Toxic exposures
Mental health

Question 19

id prevention, control, and mitigation measures for floods

Answer 19

Land use planning, floodplain management, coastal zoning
Structures: dams, levees, sea walls, sand bags to managing coasts and floodplains. Buildings that are resistant to flooding
Natural: barrier islands, mangrove forests
Early warning, evacuation, public information, search and rescue, surveillance

Question 20

id reasons for conducting community outreach after floods

Answer 20

Assist victims who can’t or don’t seek help due to geographical, monetary and disability limits.
Prevent overcrowding in the hospital from unnecessary visits
enhance surveillance and information about the situations in the community

Question 21

Scope of flood problems

Answer 21

Floods account for 40% of all world disasters

Cause the most damage worldwide