us vulnerability to natural hazards
TRANSCRIPT
Hurricanes(1899-2000)
Tornadoes(1950-2000)
Population(2000 Census)
Hurricane Landfalls/Century
Earthquake Acceleration
S5S4S3 11 – 30 31 – 728 – 10 11 – 20 21 – 40
Peak Ground Acceleration (%g) with10% Probability of Exceedance in 50 Years
41 – 10030 100,000
Values on Map Correspond to the Percentage of Each
State Within the Floodplain
2.5
2.1
2.53.0
2.1
6.5
7.05.7
6.91.7
4.5
4.9
6.06.8
1.15.2
3.1
3.2
4.47.111.0
1.5
1.0
0.6
0.6
2.5
1.5
4.3
0.8
3.7
1.3
5.3
15.9
4.5
16.6 9.5 6.1
12.2
16.9
0.1
0.9
10.7
26.6
3.3
1.7 3.6
2.3
1.9
12.7
9.7
1899 - 19271928 - 1960
1961 - 19901991 - 2000
Hurricane Tracks at Approximately 30 Year Intervals
1928 - 19601961 - 1990
Percent
0 - 55 - 1010 - 2020 - 30
Percent of Area in Floodplain by State FEMA Cost per Person in Floodplain per Year
Dollars
0 - 100100 - 10004500 - 8000
Tornado Frequency(TX, OK, KS)
0
5 0
100
150
200
250
300
350
400
450
1950 1953 1956 1959 1962 1965 1968 1971 1974 1977 1980 1983 1986 1989 1992 1995
Nu
mb
er o
f T
orn
dad
oes
50-
95
F0F1F2F3F4F5
El Niño Year(Dot proportional to event size)
La Niña
NATURAL DISASTERS result from the coincidence of natural events with the built environment. To reduce natural disasters, we need to increase awareness of natural disasters and the predictable consequences of high-risk land-use. By superimposing population density with predicted ground motion from earthquakes, historical hurricane tracks, historical tornado locations, and areas within the flood plain, we are able to identify locations of high vulnerability within the United States. Although their frequency varies considerably, the annualized losses for disaster relief from hurricanes, earthquakes, and floods are approximately equivalent and represent over 75% of federal emergency assistance. Tornadoes cause less damage, but are responsible for a significant percentage of deaths.
The costs of natural disasters have been increasing exponentially, largely due to increases in population and wealth density in disaster-prone areas. The figure above shows the federal government’s expenditures for natural disasters as a percentage of Gross Domestic Product (GDP). Even when accounting for the exponential rise in GDP over the last four decades, the costs of natural disasters have tripled.
For the purposes of this analysis, population is used not only to represent human exposure to risk, but also vulnerable societal infrastructure. In the figure above, the correlation coefficient of income and population by county is .9919. With the exception of about two dozen counties, where the estimated value is too high, and a few large counties where the estimated value is too low, population density can be used as a proxy for societal infrastructure.
In general, the number of seismic events in a region increases by a factor of 10 for each unit of decrease in magnitude. This empirical observation, known as the Guttenberg-Richter relation, applies to earthquakes in the United States. As the figure above shows, we should expect approximately 2 magnitude 8, and 20 magnitude 7 earthquakes each century.
There are about 1,500 tornadoes in the US each year. The increase, particularly in F0 tornadoes, is probably due to improved detection capabilities. The correlation with El Niño years is not well-defined.
The area of the United States within the 100-year floodplain is approximately that of Texas. At present, more than 3 million households are in floodplains, and each year, the number increases. States that have the greatest percentage of area in the floodplain however, do not necessarily incur the largest number of flood disasters on a per capita basis – perhaps reflecting better land-use policies for those states. According to FEMA, only 2% of the flood insurance policy base is responsible for nearly 40% of the payments made by the National Flood Insurance Fund.
In the last century about 170 hurricanes have struck the United States. Each year in the Atlantic, approximately six hurricanes form, with one or two making landfall. The frequency, strength, and location are affected by wind shear and sea-surface temperatures, both of which are part of the greater El Niño and multi-decadal cycles and patterns. Historical tracks show East-West oscillations in 30-year periods. If this 30-year oscillation continues, hurricanes will become more frequent along the northern part of the Eastern Coast.
Federal Disaster Relief as a Percentage of GDP
FEMA relief + 15%SBA loan activity
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0.001962 1965 1968 1971 1974 1977 1980 1983 1986 1989 1992 1995 1998
%
Fiscal Year
2
1
0
-1
-2
-3
-4
10-1-2-3-4
Aggregate Income versus Population by County
Log (County Population in Millions)
Log
(C
ou
nty
Inco
me
in B
illio
ns)
Gregory van der Vink, Sarah Apgar, Andrew Batchelor, Caroline Carter, David Gail, Andrew Jarrett, Naomi Levine, W. Jason Morgan, Michal Orlikowski, Thomas Pray, Meryl Raymar, Asher Siebert, Tsering Wangyal Shawa, Clinton Wallace
This poster was prepared for the Congressional Natural Hazards Caucus as part of the undergraduate course Geo499: Investigating Natural Disasters, taught by Gregory van der Vink at Princeton University. Support for the course was provided by the Department of Geosciences and Princeton University’s Science and Technology Council. Poster development and design by Jason Mallett, IRIS Consortium. Special thanks to David Applegate, Peter Folger, and Christel Hennet.
Each year, Congress appropriates billions of dollars in emergency assistance to states hit hard by earthquakes, floods, hurricanes, tornadoes and other natural disasters. The Senate Hazards Caucus provides ways the local, state and federal government to better prepare for and help mitigate the costs of natural disasters.
3
4
5
6
7
8
9
10
3
4
5
6
7
8
9
10
10.1 10 100 1,000 10,000 100,000 1e+06
Alaska (1964)
New Madrid, MO (1812)San Francisco, CA (1906)
Charleston, SC (1886)Loma Prieta, CA (1989)
Northridge (1994)
Long Island, NY (1884)
great earthquakenear total destruction
massive loss of life
major earthquakesevere economic impact
large loss of life
strong earthquakedamage ($ billions)
loss of life
moderate earthquakeproperty damage
light earthquakesome property damage
minor earthquakefelt by humans
Number of Events per Century
Earthquake Frequency w/ Selected Events
Mag
nit
ud
e
Total Tornadoes
Tornado Strength
El Niño / La Niña
US Vulnerability to Natural Hazards