Lecture 7: Data for monitoring natural hazards: Disaster risk reduction

Question 1

Large spatial and temporal range
of such hazards

…Need a range of different techniques to monitor them

Answer 1

Remote sensing: satellite & aircraft

Ground observations: direct sensors

Question 2

Remote sensing: satellite and aircraft

Answer 2

Can see large areas
Lower resolution
Gaps in coverage

Question 3

Ground observations: direct sensors

Answer 3

Can see limited area

Higher resolution

Question 4

Volcano hazards

Answer 4

Pyroclastic flow
Lahars / mud flow
Noxious gasses (CO2)
Earthquakes
Eruption plumes

Climate impacts
Sulphate aerosols

Question 5

Ground observations for volcanos

Answer 5

Surface deformation
Tiltmeters (changes in slope)
GPS

Seismicity
Seismographs

Gas emissions
Collected from vents and fumaroles

Question 6

Volcano detections

Gas emissions

Answer 6

Increase in gas emissions may indicate potential eruption

Question 7

Volcano detections

Ground based remote sensing

Answer 7

Perform transects beneath the plume to sum overhead concentrations across profile and find total emission.

Provides fine spatial resolution
But poor spatial coverage
To get better spatial coverage need to get higher

Question 8

Volcano detections

Volcano surface deformation

Answer 8

Stage 1: Inflation begins as magma moves into the volcano or as pressure increases in the magma chamber
Stage 2: As magma chamber inflates the sound surface above it is displaced
Stage 3: After an eruption, the magma chamber deflates.
Ground surface subsides with potential formation of crater.

Question 9

Volcano detections

Seismicity

Answer 9

Magma fractures cooler rock causing earthquakes

An increase in the number of earthquakes may indicate an imminent eruption

Question 10

What do crater lakes on volcanoes act like?

Answer 10

Calorimeters, absorbing heat given off by intruding magma

Approximately 12% of the world’s 700 or so active volcanoes have crater lakes.

Question 11

Remote sensing: satellite and aircraft

What is it?

Answer 11

Defines as ‘study of Earth and its environment from a distance via emitted or reflected electromagnetic energy”

-i.e not in contact with the object under study

Question 12

Remote sensing

Can be:

Answer 12

Ground based (tower, handheld device)
Airborne
Spaceborne

Question 13

Advantages of space borne remote sensing

Answer 13

Obtain data over large areas (e.g global)
Provide a time series of consistent data
Acquire data in inaccessible and remote areas
Potential to provide data at a high temporal frequency compared to ground observations

Question 14

Thermal observations useful for monitoring:

Answer 14

1) Volcanic monitoring
Ash (contaminates water, respiratory hazard, danger to aircraft)
Lava and pyroclastic flows (cause fatalities, destroy property)
2) Wildfire
Respiratory hazard, cause fatalities, destroy property, contaminates water

Question 15

InSAR

Answer 15

Interferometric Synthetic Aperture Radar
Maps ground deformation
Comparison of two or more radar images

Question 16

Managing hazards

Answer 16

Speed of onset (slow = drought; fast = earthquake)

Magnitude (strength/force) (e.g. wind speed, height of tide)

Frequency (return period, e.g. 1 in 100 years)

Intensity (severity/impacts) = disaster potential scales

Question 17

Hazard + Vulnerability =

Answer 17

Risk

Question 18

1. Long term planning (mitigation)

Answer 18

Aim: To eliminate or reduce the probability of a disaster, or reduce the effects of unavoidable disasters.
E.g.: undertake vulnerability analyses; active public education; implement tax incentives and disincentives to change public behaviour towards risk; re-allocate resources; introduce preventive health care.
E.g. to facilitate recovery: strengthen building codes and regulations; reconsider zoning and land-use management; disaster unemployment insurance and risk assessment studies.

Question 19

Other forms of Long Term Mitigation

Structural measures

Answer 19

e.g. engineering technologies to make infrastructure more robust to hazards.

Question 20

Other forms of Long Term Mitigation

Non-Structural measures

Answer 20

e.g. land-use planning and regulation + information dissemination + economic incentives to reduce deliberate or accidental exposure.

Question 21

Other forms of Long Term Mitigation

Risk-spreading measures

Answer 21

Risk-spreading measures e.g. economic measures to encourage higher long term preparedness, such as loss insurance.

Question 22

2. Prepare

Answer 22

Aim: Activities taken prior to a disaster, to save lives, minimize disaster damage, and enhance response operations.

E.g.: preparedness plans; emergency exercises/training; early warning systems; emergency communications systems; evacuation plans and training; mutual aid agreements; and public information/education.

Question 23

3. Respond

Answer 23

Aim: Activities immediately before, during and following a disaster to provide emergency assistance for casualties, reduce the probability of secondary damage, and speed recovery operations.

E.g.: public warning systems; notifying public authorities; mobilizing emergency personnel/equipment; emergency medical assistance; manning emergency operations centres; declaring disasters and evacuating; mobilizing security forces; search and rescue; and emergency suspension of laws.

Question 24

4. Recovery

Answer 24

Aim: Activities following a disaster, which continue until all systems return to normal or better.

E.g.: Returning life-support systems to minimum operating standards; damage insurance/loans and grants; temporary housing; long-term medical care; public information; health and safety education; reconstruction; counselling programs; and economic impact studies.