EARTHQUAKES
Earthquakes
are sudden rolling or shaking events caused by movement under the earth’s
surface. Earthquakes happen along cracks in the earth's surface, called fault
lines, and can be felt over large areas, although they usually last less than
one minute. Earthquakes still cannot be predicted.
Earthquakes In Chile
Chile
has a long history of massive earthquakes, so it is a high seismic risk zone. Earthquakes can happen at any
time of the year.
Earthquakes
in Chile mainly occurred as the result of thrust faulting on the interface
between the Nazca and South America plates. This subduction zone also
hosted the largest earthquake on record, the 1960 MW = 9.5 earthquake in
southern Chile (Valdivia).
Chile is
characterized by the largest seismicity in the world. This high seismicity allows
calibrating the Chilean Seismic Code with the observed performance of buildings
after each large quake. The last calibration was due to the El Maule earthquake
of February 27, 2010, MW = 8.8 earthquake and it was introduced in Chilean Code
NCh 433 through the Decree 60, December 2011.
After
the El Maule, Chile 2010 MW = 8.8 earthquake only 4 buildings collapsed (only considering reinforced
concrete and masonry buildings). The following table shows the performance of
Residential Buildings permitted from 1985 to 2009.
Building
that collapsed
|
:
|
4
(approximate)
|
Building
to be demolished
|
:
|
50
(estimate)
|
No of
building 3 + stories
|
:
|
9,974
|
No of
buildings 9 + stories
|
:
|
1,939
|
|
|
|
Failures
in 3 + story buildings
|
:
|
0.5%
|
Failures
in 9 + story buildings
|
:
|
2.8%
|
Tsunamis In Chile
Almost
all earthquakes in Chile are produced along the Chilean shore, so always a
Tsunami could be expected after an earthquake.
Earthquake-induced
movement of the ocean floor most often generates tsunamis. If a major
earthquake or landslide occurs close to shore, the first wave in a series could
reach the beach in a few minutes, even before a warning is issued. Areas are at
greater risk if they are less than 10 m.a.s.l. and within 2 km. Drowning is the
most common cause of death associated with a tsunami. Tsunami waves and the
receding water are very destructive to structures in the run-up zone. Other
hazards include flooding, contamination of drinking water, and fires from gas
lines or ruptured tanks.
2015 Illapel Earthquake (MW = 8.3)
On September 16, 2015, a powerful 8.3-magnitude earthquake struck off the
Chilean coast
(Illapel, Coquimbo Region), triggering a tsunami (waves of up to 4.5m, 13
deaths, 6 missing, and 1 million evacuated). The initial quake lasted three
minutes, and was followed by several aftershocks greater than magnitude six.
Tall
buildings swayed and car alarms were set off in Santiago (229 km), Buenos Aires
(1,110 km), and the earthquake was felt in Sao Paulo (more than 2,600 km).
Although
causing damage in the hundreds of millions, mainly due to the tsunami, the
Illapel earthquake's low death toll relative to the 525 casualties of the
significantly more powerful 2010 Chile earthquake was credited, in part, to its
localization in a less-populated region, better coastal preparedness and an
improved tsunami warning system, the longstanding enforcement of seismic
building codes, and an improved emergency response.
Mining Industry
In the
north of Chile are located the biggest copper mines, but workers were safe
and operations were not damaged by the earthquake.
- Codelco
staff and operations were unharmed in the quake that prompted the evacuation of
personnel from facilities in coastal areas, amid a tsunami warning.
- Workers
at AMSA Los Pelambres operation were safe and installations hadn’t suffered any
damage.
- Anglo
American, BHP Billiton and Pan Pacific Copper Co. mines were also unaffected.
SAFETY RULES
Some safety
rules that you have to consider in case of an earthquake in Chile, or any other
seismic country, are the following (based on FEMA
and Chilean authorities recommendations):
Before An Earthquake
- Look
around places where you spend time. Identify safe places such as under a
sturdy piece of furniture or against an interior wall in your home, office or
school so that when the shaking starts, you Drop to the ground, Cover your
head and neck with your arms, and if a safer place is nearby, crawl to it and
Hold On.
- Practice
how to “Drop, Cover, and Hold On!”
- To
react quickly you must practice often. You may only have seconds to protect
yourself in an earthquake.
- Before
an earthquake occurs, secure items that could fall and cause injuries (e.g., bookshelves,
mirrors, light fixtures).
- Store
critical supplies (e.g., water, medication) and documents.
- Plan how you will communicate with family members, including multiple
methods by making a family emergency communication plan.
- When
choosing your home or business, check if the building is earthquake resistant
per local building codes. In Chile, all buildings are earthquake resistance
in accordance with its seismic codes (NCh433 and NCh2369).
During An Earthquake
If you
are inside a building:
- Stay where you are until the shaking stops. Do not run outside. Do not get in a
doorway as this does not provide protection from falling or flying objects, and
you may not be able to remain standing.
- Drop
down onto your hands and knees so the earthquake doesn’t knock you down. Drop
to the ground (before the earthquake drops you!)
- Cover
your head and neck with your arms to protect yourself from falling debris.
- If
you are in danger from falling objects, and you can move safely, crawl for
additional cover under a sturdy desk or table.
- If
there is low furniture or an interior wall or corner nearby, and the path is
clear, these may also provide some additional cover.
- Stay away from glass, windows, outside doors and walls, and anything
that could fall, such as light fixtures or furniture.
- Hold
on to any sturdy covering so you can move with it until the shaking stops. Stay
where you are until the shaking stops.
If
getting safely to the floor to take cover won’t be possible:
- Identify an inside corner of the room away from windows and objects that
could fall on you.
The earthquake safety specialist advises getting as low as possible to the
floor. People who use wheelchairs or other mobility devices should lock their
wheels and remain seated until the shaking stops. Protect your head and neck
with your arms, a pillow, a book, or whatever is available.
If you
are in bed when you feel the shaking:
- If
you are in bed: Stay there and Cover your head and neck with a pillow. At
night, hazards and debris are difficult to see and avoid; attempts to move
in the dark result in more injuries than remaining in bed.
If you
are outside when you feel the shaking:
- If you are outdoors when the shaking starts, move away from buildings,
streetlights, and utility wires. Once in the open, “Drop, Cover, and Hold On.” Stay there until the
shaking stops. This might not be possible in a city, so you may need to duck
inside a building to avoid falling debris.
If you
are in a moving vehicle when you feel the shaking:
- If
you are in a moving vehicle, stop as quickly and safely as possible and stay in
the vehicle. Avoid stopping near or under buildings, trees, overpasses, and
utility wires. Proceed cautiously once the earthquake has stopped. Avoid
roads, bridges, or ramps that the earthquake may have damaged.
If you
are in the coastline (Tsunami hazard risk):
- Follow the evacuation order issued by authorities and evacuate
immediately.
- Move inland to higher ground immediately. Pick areas 30 m.a.s.l. or go as far as 3 km
inland, away from the coastline. If you cannot get this high or far, go as
high or far as you can. Every meter inland or upward may make a difference.
- Stay away from the beach. Never go down to the beach to watch a tsunami
come in. If you can
see the wave you are too close to escape it. CAUTION - If there is noticeable
recession in water away from the shoreline this is nature's tsunami warning and
it should be heeded. You should move away immediately.
- Save
yourself - not your possessions.
- Remember to help your neighbors who may require special assistance -
infants, elderly people, and individuals with access or functional needs.
After an Earthquake
- Follow the instructions of local emergency management officials.
- When
the shaking stops, look around. If there is a clear path to safety, leave the
building and go to an open space away from damaged areas.
- If you are in the coastline, move inland to higher ground immediately.
- If
you are trapped, do not move about or kick up dust.
- If
you have a cell phone with you, use it to call or text for help.
- Tap
on a pipe or wall or use a whistle, if you have one, so that rescuers can
locate you.
- Once
safe, monitor local news reports via battery operated radio, TV, social media,
and cell phone text alerts for emergency information and instructions.
- Be
prepared to “Drop, Cover, and Hold on” in the likely event of aftershocks.
Listen to Local Officials
Learn about
the emergency plans that have been established in your area by your state and
local government. In any emergency, always listen to the instructions given
by local emergency management officials.
“Drop, Cover, and Hold on”
(FE-2015)
