Spatial and temporal distribution of hazards

Question 1

Natural hazards are

Answer 1

Natural Hazards are naturally-occurring physical phenomena caused by either rapid or slow onset events having atmospheric, geologic and hydrologic origins at a global, regional, national or local scale. They include earthquakes, volcanicc eruptions, landslides, tsunamis etc (UNESCO, 2013)

Question 2

Natural disasters are

Answer 2

“Natural disasters are the consequences or effects of natural hazards, but natural phenomena do not automatically spell disaster” (UNESCO, 2013)

Question 3

Importance of understanding physical characteristics

Answer 3

Identifying common features – generalizations
Mechanistic controls – potential for damage/destruction
Linking physical processes to mitigation measures

Question 4

Categorization of hazards - typologies

Answer 4

Typologies provide a useful framework for identifying similarities and making generalisations about hazardous events
Typologies also promote sound management practices.

Question 5

Origin based classifications

Answer 5

Atmosphere/hydrosphere, lithosphere, and biosphere (Chapman, 1999)
Endogenous (forces from within the earth), exogenous (focus above the earth surface)and anthropogenous
EM-DAT – natural and technological (Hydro-meteorological and geophysical)

Question 6

Primary and secondary hazards

Answer 6

primary e.g. earthquakes, storm surges, volcanic eruptions etc. Secondary hazards e.g. landslides, tsunamis, pyroclastic flows etc.

Question 7

Magnitude

Answer 7

Measure of strength/force
Comparison of extreme events in space and time
Applicable to all hazards – baselines

Question 8

Magnitude Limitations

Answer 8

Bad indicator of impact and hazardousness
Scale(s) of measurement –
what do they mean?

Question 9

Houghton et al (2013) measured

Answer 9

During explosive eruptions of Kilaueau in 2008 we constructed the first time deposits of bulk volumes to demonstrate exponential thinning from the vent

Question 10

Houghton et al (2013) VEI

Answer 10

The VEI is increasingly being used as a measure of magnitude of explosive eruptions

Question 11

Houghton et al (2013) The 2008 eruption deposits demonstrate

Answer 11

A problem for the use of VEI, as originally defined, which classifies small, yet ballistic producing explosive eruptions at Kilaueau as non explosive

Question 12

Musson et al (2010) scales to measure earthquakes

Answer 12

Numerous macroseismic scales as an index of shaking with the number of important scales adopted much smaller, maybe 8.

Question 13

Musson et al (2010) Importance of scale

Answer 13

The extent to which a scale guides the user to arrive at a correct assessment of the intensity is a measure of the quality of the scale

Question 14

Musson et al (2010) a useful scale must consider

Answer 14

Applicability - diagnostics; consistency - are diagnostics equivalent; discrimination - diagnostics might not be an expression of intensity; number of degrees - depends on ability to resolve intensities; regularity - poor practice and isoseismal maps; reliability - seek a method that reduces subjectivity.

Question 15

Doswell et al (2009) The F scale

Answer 15

Was originally formulated as a peak wind speed scale for tornadoes; it has been implemented using damage to estimate wind speed

Question 16

Doswell et al (2009) The EF scale

Answer 16

Recently, the F scale has been replaced in the US by an official system for rating tornado intensity

Question 17

Doswell et al (2009) Conclusion

Answer 17

The adoption of the EF scale may have been premature, especially if it is to serve as a model for how to rate tornadoes outside the US

Question 18

Duration

Answer 18

Hazard type – effects on point/area (space)
The relationship between duration and hazard planning/management
Duration and period of onset
Duration and scale of impact (area affected)

Question 19

Duration: Boxing Day Tsunami

Answer 19

Cause – megathrust earthquake – Indian plate subducted by Burma plate
Magnitude 9.0 – revised estimate – 2005
Hypocentre, N Sumatra, 1300km rupture
Teletsunami – vertical seabed displacement
Travel characteristics
Travel time 15min-7 hours

Question 20

Temporal distribution - frequency

Answer 20

Qualitative or quantitative description
 The relationship between recurrence and magnitude
 The role of historical records
 Standardisation of scales
 Technological advances

Question 21

Smith et al (2010) hurricane activity increase

Answer 21

North Atlantic hurricane activity has increased substantially since the 1970s, but whether this is attributable to natural internal variability or external forcing has not been resolved.

Question 22

Smith et al (2010) hurricane frequency predictable?

Answer 22

Hurricane frequency is potentially predictable, because climate models can directly simulate year-to-year variations in Atlantic tropical storm frequency, if forced by observed SST’s.

Question 23

Smith et al (2010) Found

Answer 23

physically based model evidence of externally forced changes in hurricane frequency, albeit from a single modelling system. Smith’s results show that predictions of hurricane frequency are viable beyond the seasonal scale, and further elucidate causes of hurricane variability.- decadal predictions using GCMs

Question 24

Frequency: Tropical cyclones: IPCC Special Report (2012)

Answer 24

Detection of trends (frequency, intensity and duration) remains a challenge
Past records – heterogeneous due to observing technology and reporting protocols
Regional trends in North Atlantic – fidelity disputed
Steady global TC frequency – inter-annual and multi-decadal trends within basins
Projected increase in most intense storms

Question 25

Relative simplicity of seasonality

Answer 25

The realm of hydro-meteorological hazards
Seasonality/periodicity
Predictability – timing and location
The relationship between seasonality and spatial location
Management hampered by uncertainties surrounding frequency and intensity
Limitations – e.g. UK snow and EU floods

Question 26

Moving Seasons - Westerling et al (2006)- wildfire increase

Answer 26

Western US wildfire activity is widely thought to have increased in recent decades

Question 27

Moving Seasons - Westerling et al (2006) - Database

Answer 27

Compiled a comprehensive database of large wildfires in western US forests since 1970 and compared it with hydroclimatic and land surface data

Question 28

Moving Seasons - Westerling et al (2006) - Findings

Answer 28

Wildfire has increased in the mid 1980s - the greatest increase occured in mid elevation Northern Rockies where land use has relatively little effect on fire risks

Question 29

Importance of diurnal factors

Answer 29

Thunderstorms and tornadoes – physical controls in specific areas
Time of day – important , regardless of hazard type

Question 30

Space: the barrier to generalisation

Answer 30

Multiple physical parameters of a single hazard provide a stronger basis for comparison
Characterisation of hazard through characteristics = problematic – variation in properties at different spatial scales

Question 31

Areal extent

Answer 31

• the area affected – hazard type, environmental constraints

Question 32

Spatial distribution

Answer 32

– the space in which hazards occur

Question 33

Berz et al (2001) Munich Re’s Geoscience research group

Answer 33

Published its first world map of natural hazards in 1978

Question 34

Berz et al (2001) Revised map

Answer 34

In 1998 the map was revised with all first time recorded data recorded and analysed using GIS, background info of earthquakes, volcanism, windstorm, floods etc added in and hazard info has been stated as numbers so it can be checked

Question 35

Peduzzi et al (2005) - there is a call for

Answer 35

An improved methodology allowing comparison of natural hazard impacts at a global level

Question 36

Peduzzi et al (2005) - data needed

Answer 36

In order to associate reported impacts with affected elements and socio economic or geophysical contextual parameters, geographical location and extent of hazards is needed.

Question 37

Peduzzi et al (2005) - results

Answer 37

Presents an improved automated procedure for mapping a larger disastrous hazard events using GIS. Up to 82% of the events and 88% of the reported victims were georeferenced.

Question 38

Dixon et al (2011) - study suffers

Answer 38

This study suffers from shortcomings associated with the tornado database. By avoiding separation by F scale and by using local tornado days rather than raw tornado events, major potential problems with the dataset have been avoided

Question 39

Dizon et al (2011) - KDE method

Answer 39

The KDE method provides a robust assessment of tornado threat in a particular area, but the calculations are limited by the quality of the recorded tornado paths. – it is assumed that an employed kernel radius (40.25km) is sufficient to mask any spatial areas, but some events that travelled significant distanced might have been reported as single-point touchdown

Question 40

Dixon et al (2011) - tornado-day density and dixie valley

Answer 40

Statistical analysis shows that regions with similar tornado-day densities are located throughout the Great Plains, the Corn Belt, and the Deep South without areas of statistically significant differences separating them.
It is possible that this line of relatively little tornado activity is partially responsible for the emergence of “Dixie Alley” as a separate region.

Question 41

Brooks et al (2013)

Answer 41

showed that spatial patterns vary dramatically with seasons

Question 42

Dilley et al (2005) - world bank study

Answer 42

Revealed that more than half the world’s population were exposed to one or more natural hazards

Question 43

Bower (2011) trend in hydro met data

Answer 43

22 studies of economic losses data over at least 30 years for hydro met disasters - in 14 cases the normalized data showed no trend.

Question 44

Garner and Huff (1997) reporting

Answer 44

Medium reporting shows an excessive concentration on the emergency phase of a disaster, especially if striking images of distressed victims are available

Question 45

NOAA - reporting time of tornadoes

Answer 45

the average amount of time between a tornado warning and the arrival of a storm is about 13 minutes

Question 46

National Geographic article, March 2015

Answer 46

We don’t understand how tornadoes die. Brooks says tornadoes tend to follow the general movement of the thunderstorm they are associated with, but the route can be erratic.