Enquiry Question 2: Why do some tectonic hazards develop into disasters?

Question 1

Natural Hazard

Answer 1

A natural process/event that has the potential to threaten life and property

Question 2

Natural Disaster

Answer 2

T realisation of a hazard when it causes damage/injury (e.g. 10 or more people are killed, or 100 people or more are affected

Question 3

Vulnerability

Answer 3

The ability to anticipate, cope and recover from a natural hazard/disaster.

Question 4

Resilience

Answer 4

The ability to protect lives, livelihoods and infrastructure from damage and to repair damage.

Question 5

Hazard risk equation

Answer 5

Risk (R) equals hazard (H) multiplied by vulnerability (V), divided by the capacity to cope (C)

Question 6

Pressure and Release Model (PAR)

Answer 6

A model which examines the underlying causes of a disaster - 1) the factors affecting vulnerability, and 2) the natural processes/hazard itself.

Question 7

Social impact

Answer 7

The effects of an event/process on people and their health, livelihoods and wellbeing.

Question 8

Economic impact

Answer 8

The effects of an event/process on business, trade, industry, employment and infrastructure.

Question 9

Environmental impact

Answer 9

The effects of an event/process on the landscape and ecology.

Question 10

magnitude

Answer 10

The size of the tectonic event - either the size of the volcanic eruption (VEI) or the amount of energy released from the hypocentre during an earthquake (MMS)

Question 11

intensity

Answer 11

The strength of shaking and resulting damage from an earthquake (e.g. Mercalli scale)

Question 12

Moment Magnitude(Mw) Scale

Answer 12

Based on measurement of the maximum motion recorded by a seismograph, and also based of the concept of seismic moment (Source: USGS)

Question 13

Mercalli scale

Answer 13

Measurement of the effects of an earthquake experienced by people. Lower values generally deal with the manner in which the earthquake is felt by people. Higher values are based on observed structural damage.

Question 14

Volcanic Explosivity Index (VEI)

Answer 14

A relative scale that enables explosive volcanic eruptions to be compared with one another. It considers the volume of pyroclastic material ejected (e.g. tephra, ash), the height of the eruption column and the duration of the eruption.

Question 15

Speed of Onset

Answer 15

How quickly the peak of the hazard event occurs

Question 16

Areal extent

Answer 16

The size of the physical area affected by the event.

Question 17

duration

Answer 17

The length of the event

Question 18

frequency

Answer 18

The number of events in a given period of time.

Question 19

spatial predictability

Answer 19

How easy it is to pin point/estimate when an event will happen

Question 20

Hazard Profile

Answer 20

A diagram that illustrates the main characteristics of different types of tectonic hazards)

Question 21

Governance

Answer 21

The way in which local and national governments plan for, and respond to, tectonic hazards. This can contribute to an areas vulnerability and resilience.

Question 22

Inequality of access

Answer 22

The way in which not everyone has the same opportunities regarding education, healthcare, housing and income. This can affect people’s vulnerability and resilience.

Question 23

Population density

Answer 23

The number of people per sq. km of land area

Question 24

degree of urbanisation

Answer 24

The proportion of people living in urban areas. Also closely linked to higher population densities.

Question 25

Seismic moment

Answer 25

a measure of the size of an earthquake based on the area of fault rupture, the average amount of slip, and the force that was required to overcome the friction sticking the rocks together that were offset by faulting

Question 26

Slip

Answer 26

the relative displacement of formerly adjacent points on opposite sides of a fault (Source: USGS)

Question 27

Strike-slip fault

Answer 27

vertical (or nearly vertical) fractures where the blocks have mostly moved horizontally

Question 28

Dip slip fault

Answer 28

inclined fractures where the blocks have mostly shifted vertically. If the rock mass above an inclined fault moves down, the fault is termed normal, whereas if the rock above the fault moves up, the fault is termed reverse.

Question 29

Thrust fault

Answer 29

A reverse fault with a dip of 45 degrees or less.