A2 Natural Hazards
Earthquakes
Volcanoes
Mass Movements
Cyclones
OCR Synoptic Paper Outline
•Hazards Structure
•Causes, Effects etc.
•Park Model (1991)
•Hazards Modules:
Earthquakes
Volcanoes
Mass Movements
Tropical Cyclones
2 weeks
2 weeks
2 weeks
2 weeks
1. Earthquakes
MEDC - LEDC Earthquake Case Studies
MEDC Case Studies
1. Kobe, Japan, 17 Jan 1995; RS = 7.2; Deaths
= 5,500
2. Los Angeles, USA, 17 Jan 1994; RS = 6.6;
Deaths = 40
3. San Fransisco, USA, 17 Oct 1989, RS = 7.1;
Deaths = 63
4. Alaska, USA, 27 March 1964, RS = 9.2;
Deaths = 131
MEDC - LEDC Earthquake Case Studies
LEDC Case Studies
1. Izmit, Turkey: 17 August 1999; RS = 7.4;
Deaths = 40,000~
2. Khillari, India: 30 Sept 1993; RS = 6.4;
Deaths = 25,000
3. Gujurat, India: 26 Jan 2001; RS = 7.4;
Deaths = 60,000~
4. Armenia: 7 Dec 1988; RS = 7.0; Deaths =
25,000 - 100,000
The seismic gap theory
The part of an active fault that has experienced little or no seismic
activity for a long period, indicating the build up of stresses that are
useful in predicting earthquakes
1969-1989
3 weeks after 1989
Liquefaction
Japan 1963
Golden Gate
Bridge
Port and wharf facilities are often located in areas
susceptible to liquefaction, and many have been
damaged by liquefaction in past earthquakes.
Most ports and wharves have major retaining
structures, or quay walls, to allow large ships to
moor adjacent to flat cargo handling areas. When
the soil behind and/or beneath such a wall
liquefies, the pressure it exerts on the wall can
increase greatly - enough to cause the wall to slide
and/or tilt toward the water.
Liquefaction caused major damage to port facilities
in Kobe, Japan in the 1995 Hyogo-ken Nanbu
earthquake.
Note the
subsidence
in the port
in Kobe due
to
liquefaction
A2 - Alaska Case Study
ALASKA, MARCH 27, 1964 RS= 9.2
Alaska earthquake of 1964
Prince William Sound, Alaska 1964 03:36:14 UTC,
9.2 on the richter scale
Landslides in Anchorage caused heavy
This great earthquake and ensuing tsunami took 125 lives (tsunami
damage.
Huge slides occurred in the
110, earthquake 15), and caused about $311 million in property
downtown
business
section,
atmany
Government
loss. Earthquake
effects were
heavy in
towns, including
Anchorage,
Portage,Heights.
Seward and The
Valdez.
Hill,
and at Kodiak,
Turnagain
largest
about 120 km Northwest
of the
epicentre, at
sustained the
andAnchorage,
most devastating
landslide
occurred
most severe damage to property. About 30 blocks of dwellings and
Turnagain
Andamaged
area ofor about
130
commercial Heights.
buildings were
destroyed
in the downtown
area. The
Penny Company
building was damaged
acres
wasJ.C.
devasted
by displacements
thatbeyond
repair; the Four Seasons apartment building, a new six-story
broke
the ground into many deranged blocks
structure, collapsed; and many other multi-storey buildings were
that
were heavily.
collapsed
and in
tilted
at allwere
angles.
damaged
The schools
Anchorage
almost
devastated.
The Government
Hill Grade
School, sitting astride a
This
slide destroyed
about
75 private
huge landslide, was almost a total loss. Anchorage High School and
houses.
Water
mains
and gas,
sewer,
Denali Grade
School
were damaged
severely.
Duration of the
shock was estimated
at 3 minutes.
telephone,
and electrical
systems were
disrupted throughout the area.
The earthquake was accompanied by vertical displacement
over an area of about 520,00 square km. The major area of
uplift trended Northeast from southern Kodiak Island to
Prince William Sound and trended east-west to the east of
the sound.
Vertical displacements ranged from about 11.5m of uplift to
2.3m of subsidence relative to sea level. Off the Southwest
end of Montague Island, there was absolute vertical
displacement of about 13 - 15m.
This shock generated a tsunami that devastated many towns
along the Gulf of Alaska, and left serious damage at Alberni
and Port Alberni, Canada, along the West Coast of the
United States (15 killed), and in Hawaii. The maximum wave
height recorded was 67m at Valdez Inlet. It was also
recorded on tide gages in Cuba and Puerto Rico.
Close-up of Government Hill elementary school, which was
destroyed by the Government Hill landslide. Anchorage, Alaska.
The waterfront at Seward a few months after the earthquake,
looking north. Note the "scalloped" shoreline left by the
underwater landslides that severed tracks in the railroad yard
which dangle over the landslide scarp and the windrow-like heaps
of railroad cars and other debris thrown up by the tsunami waves.
Alaska.
Uplifted sea floor at Cape Cleare,
Montague Island, Prince William
Sound, in the area of greatest
recorded tectonic uplift on land (33
feet).
Tsunami damage on Kodiak island in Alaska
One span of the "Million Dollar" truss-bridge of the
former Copper River and Northwestern Railroad was
dropped into the Copper River by the earthquake, and
the other truss spans were shifted on their piers.
Close-up of damaged homes at Turnagain
Heights landslide, Anchorage.
The Turnagain Heights landslide in Anchorage. Its
length was about 1.5 miles; its width was about .25 to
.50 miles.
This landslide reduced to rubble many of the finer
homes of the city. Failure here, and in the "L" Street,
Fourth Avenue, and Government Hill landslides in
Anchorage occurred on horizontal or near horizontal
slip surfaces in the Bootlegger Cove Clay, a marine
silt.
A subsidence trough (or graben) formed at the head of the
"L" Street landslide in Anchorage during the earthquake. The
slide block, which is virtually unbroken ground to the left of
the graben, moved to the left. The subsidence trough sank 7
to 10 feet in response to 11 feet of horizontal movement of
the slide block. A number of houses seen in this photograph
were undercut or tilted by subsidence of the graben. Note
also the collapsed Four Seasons apartment building and the
undamaged three story reinforced concrete frame building
beside it, which are on the stable block beyond the graben.
.
This truck at Lowell Point, 2 miles from Seward,
was bent around a tree by the surge waves
generated by the underwater landslides along
the Seward waterfront. The truck was about 32
feet above water level at the time of the
earthquake.
A detail illustrating the
violence of the surge
waves that struck
Whittier: man holds
mounted tire where
wave has driven a
piece of wood through
the tire
The rails in this approach to a railroad bridge near the head of
Turnagain Arm were torn from their ties and buckled laterally by
channelward movement of the river banks during the earthquake
.
Trees up to 24 inches in diameter and between 88
and 101 feet above sea level were broken and
splintered by the surge wave generated by an
underwater landslide in Port Valdez, Prince
William Sound.
On Tuesday, January 17, at 5:46 a.m. local time, an earthquake of magnitude
7.2 (Mj)1 struck the region of Kobe and Osaka in south-central Japan. This
region is Japan’s second-most populated and industrialized area, after Tokyo,
with a total population of about 10 million. The shock occurred at a shallow
depth on a fault running from Awaji Island through the city of Kobe, which in
itself has a population of about 1.5 million. Strong ground shaking lasted for
about 20 seconds and caused severe damage over a large area.
Nearly 5,500 deaths have been confirmed, with the number of injured people
reaching about 35,000. Nearly 180,000 buildings were badly damaged or
destroyed, and officials estimate that more than 300,000 people were
homeless on the night of the earthquake.
The life loss caused by the earthquake was the worst in Japan since the 1923
Great Kanto Earthquake, when about 140,000 people were killed, mostly by
the post-earthquake conflagration. The economic loss from the 1995
earthquake may be the largest ever caused by a natural disaster in modern
times. The direct damage caused by the shaking is estimated at over ¥13
trillion (about U.S.$147 billion). This does not include indirect economic
effects from loss of life, business interruption, and loss of production.
One of the key factors in loss of life and
damage to buildings in the Kobe
earthquake was the extend of the fires
that resulted.
The risks are particularly high in Japan because of
•high population densities;
•very narrow streets and alleys, which cannot act
as fire breaks;
•numerous old wood-frame smaller commercial
and residential buildings mixed in the commercial
zones of towns;
•unanchored or unprotected gas storage tanks or
heaters;
• and a mix of collapse-prone old buildings in all
built-up areas
Nagata ward at
4.30pm on Jan
17th.
KFD
Water
had
forminimal
fire-fighting
staffing
purposes
on dutywas
at the
available
time offor
the2 to 3
earthquake,
hours, including
possibly
the use
because
of underground
the previous
cisterns.
day had
been
Subsequently,
a holiday. water
Initial was
actions
available
included
only
recalling
from tanker
off-duty
personnel
trucks. KFD
and
attempted
responding
to supply
to fire calls.
waterApproximately
with a fireboat
100
and fires
relaybroke
system,
out but
within
thisminutes,
was unsuccessful
primarily indue
densely
to the
built-up,
relativelylow-rise
small hose
areas
used
of the
by central
KFD. An
city,
EQE
which
engineer
comprise
overflew the
mixed
area
residential-commercial
at about 5:00 p.m. onoccupancies,
January 17 and
predominantly
was able to observe
of wood
allconstruction.
of the larger Within
fires (about
1 to 2eight
hours,
in
several
all) fromlarge
an altitude
conflagrations
of less than
had 300
developed.
meters.There
No firewere
astreams
total of were
142 fires
observed,
reported
and
in all
Kobe
firesonwere
January
burning
17. Fire
response
freely—several
was hampered
with flames
by 6extreme
meters traffic
or more
congestion,
in height.
and
No fire
collapsed
apparatus
houses,
werebuildings,
observedand
in the
rubble
vicinity
in the
of the
streets.
large fires,
Because
although
of the
firenumerous
apparatuscollapses,
could be seen
manyat
areas
other were
locations
inaccessible
(their activities
to vehicles.
were unclear from the
air). Some residents formed bucket brigades (with
sewer water) to try to control the flames.
.
A typical street scene in a residential and light
commercial area of Kobe. A house has collapsed,
blocking the very narrow street and preventing
access to the area by the fire department.
Thousands of narrow streets were blocked like this.
In other areas, many of the collapses were
traditional buildings with ground-floor stores or
shops and second-floor residential units.
Aftershock Maps from Kandilli Observatory and
Research Institute
This picture is on the far east end of the rupture. The fault went
directly through the school - the chalkboard read something like:
"We're all happy because school is out".
This is where 6 large apartments buildings all were completely
flattened. Luckily they were uninhabitated. Residents were
supposed to have moved in during June, but were delayed. The
fault is seen in the foreground. Aykut Barka has a photo taken of
this area from a helicopter.
In 1988 an earthquake at a magnitude of
Armenia
6.9 hit the country of
it
destroyed 58 villages and 21 cities. Four
minutes after the earthquake hit an
aftershock of 5.8 hit the country. Nearly
70% of the buildings were destroyed in
the quake.The earthquake hit at 11:41
a.m right in the middle of the school
day.
Conclusion
•Location of earthquake - proximity to local
people groups
•Oil Industry and ports located on the
southern coast - e.g. Valdez, Anchorage
•Large size of the Alaskan State
•Preparedness backed up by US Government
and work of U.S.G.S.
•Finances available for Tsunami early warning
centres
2. Volcanoes
Mount Pinatubo
Mount St Helens
Lava flow from the
north cuts 50 metrewide swathe through
Goma Flow stops as it
reaches Lake Kivu Part
of the airport runway
under lava Earth
tremors continue,
raising fears of further
eruptions
3. Mass Movement Hazards
Mass Movement Types
1. Heave
(Wetting and Drying / Freezing and Thawing)
2. Flow (Material does not retain its form)
1. Soil Creep
2. Solifluction
•Increasing Speed
3. Earthflow / Debris Flow
•Increased Water Content
4. Mudflow
3. Slides
1. Landslide
2. Rotational Slump
3. Debris / Rock Avalanche
4. Rockfall
The Slumgullion earth flow in the San Juan
Mountains of south-western Colorado.
A rockslide in the Front Ranges of the Rocky
Mountains in south-western Alberta.
Slopes - Balance between:
•FORCE (EXOGENETIC)
•RESISTANCE (ENDOGENETIC)
STRESS > STRENGTH = MASS MOVEMENT
Slope Failure is due to:
1.Increase in Stress (i.e. the
forces attempting to pull a
mass downslope)
2.Reduction in Internal
Resistance (Shear Strength)
The Aberfan Disaster
21 October 1966
4. Tropical Cyclones
The
baby
born
in a
tree
Hurricane Gilbert
The Story of Bangladesh