What are the world’s riskiest cities when it comes to natural disasters?
For the insurance industry it seems an ever-more urgent question, so
last year one reinsurance company set out to assess 616 cities around
the world for their risk of earthquake, hurricanes and cyclones, storm
surge, river flooding and tsunami. Here are Swiss Re’s overall top 10
most risky cities:
With 37 million inhabitants
living under the threat of earthquakes, monsoons, river floods and
tsunami, the Tokyo-Yokohama region is by far the riskiest in the world:
an estimated 80 per cent of Tokyoites, or 29 million, are potentially
exposed at any one time to a very large earthquake.
Japan is also the
country most exposed to tsunami risk, as the country’s urban centres are
dotted with an almost perverse accuracy along the Ring of Fire, the
active faults of the western Pacific.
The Great Kanto Earthquake of 1923
devastated both Tokyo and Yokohama, killing an estimated 142,800
people.
Built just off the Philippines
trench, Manila is one of the most risk-plagued cities you can possibly
live in. As well as the substantial earthquake risk, high wind speeds
are a severe threat: the powerful typhoon Haiyan that swept the country
last year was one of the strongest ever to make landfall.
It destroyed
several central islands, ruined the coastal city of Tacloban and killed
thousands.
This near-unbroken urban
conglomeration, including Hong Kong, Shenzhen, Dongguan, Macau and
Ghangzhou, is home to more than 42 million people.
One of China’s
economic jewels (estimated GDP: $690bn or Dh2.5 trillion) is spread
across a flood plain threatened by all manner of natural disasters:
it
is the number one metropolitan area for storm surge, with 5.3 million
people affected, the third-highest for cyclonic wind damage (17.2
million), and the fifth riskiest city for river floods.
Osaka-Kobe is home to 14.6 million
people living under the threat of earthquakes such as the one that
killed thousands of people in 1995. It also suffers from brutal storms
and the risk of river flooding.
And then there are the storm surges, in
which heavy winds from typhoons of the kind that hit east Asia whip up
gigantic waves: the metropolitan area’s location on a large coastal
plain means three million people are at risk. It is also the third-most
tsunami-prone city in the world.
Fully 40 per cent of Jakarta is
below sea level; it lies in a flat basin with soft soil near a fault
line. This means earthquakes can be particularly dangerous to its 17.7
million inhabitants, as the soft soil can magnify the intensity of the
tremors.
Quakes can also liquify Jakarta’s poorly drained soil, causing
the ground to lose its structural integrity and react like a liquid. Add
to that Jakarta’s risk of river flood and it becomes one of the most
exposed cities on the planet.
6 Nagoya, Japan: Tsunami risk dominates in the Pacific.
The most exposed cities, dotted along the active faults of the western
ocean, are in Japan – led by Tokyo-Yokohama and Nagoya, each with around
2.4 million people potentially affected.
With 12 million people in
total at great risk, tsunamis affect by far the fewest people of the
great five natural disasters analysed here – but the death tolls can be
enormous.
River floods also affect Kolkata,
with 10.5 million people at risk – but the eastern Indian city is also
fifth in terms of tsunami risk, with more than half a million people
exposed.
It is also threatened by hurricanes, human-made disaster like fire and rampant transportation vehicle accidents.
With so many cities built on
flood plains and river deltas, flooding is the most common risk they
face. India and China face the most significant risks; with 11.7 million
residents directly threatened, Shanghai is a particular hot spot for
flooding, but other such risky cities include Bangkok, Mexico City,
Baghdad, Paris and Doha.
Its location on the San
Andreas Fault makes Los Angeles one of the most earthquake-prone cities –
although not as vulnerable to tsunami as might be expected. Subduction
zones, where oceanic plates dive underneath the continental crust,
generally create much larger tsunamis than so-called “strike-slip”
faults such as the San Andreas and Northern Anatolian faults.
Small
comfort to the 14.7 million inhabitants of the area threatened by
earthquake.
San Andreas
fault or the Pacific Ring of Fire as being the riskiest zones for
earthquakes, but not everyone is immediately aware that the Northern
Anatolian fault is one of the most dangerous in the world.
The entire
13.6 million population of Tehran is exposed, as are the residents of
Bucharest, Tashkent, the capital of Uzbekistan, and much of Turkey.
The
last quake in Tehran was in 1830, and its building regulations are
shakily followed at best – making it a city living on borrowed time.
Source: Agencies
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