The document summarizes information about two recent earthquakes - the 2004 Sumatra earthquake and the 2010 Haiti earthquake. The Sumatra earthquake was one of the deadliest natural disasters, killing over 230,000 people across 14 countries. It had the longest fault rupture in history. The Haiti earthquake killed over 222,000 people and left over 1 million homeless. Both earthquakes caused massive destruction, though the death toll in Haiti was higher due to its much denser population. The document also provides background on measuring earthquakes using the Richter scale.

1. EARTH
QUAKES!
Earthquakes are one of the most destructive forces on
Earth, and have shaped the planet’s surface for billions
of years. In this study we examine two recent earth-
quakes, in Sumatra and Haiti.
SUMATRA
The earthquake that occurred on December 26th, 2004 and
devastated Sumatra, Indonesia, was one of the deadliest natu-
ral disasters in recorded history. It killed nearly 230,000 peo-
ple in fourteen countries and sent hundred-foot-tall waves
across the Indian Ocean, swallowing up countless costal vil-
lages. It had the longest duration of faulting — friction of
tectonic plates — of any earthquake in history, lasting be-
tween 8 and 10 minutes. It caused smaller earthquakes as far
away as Alaska, and caused the entire planet to vibrate as
much as one centimeter1.
The seismic rupture occurred near the middle of the Indian
Ocean, where tectonic plates (fault surfaces) that normally
move at centimeters per year suddenly moved fifteen meters
over the course of several minutes. This caused a sudden ver-
tical rise of the sea floor, which displaced massive amounts
of water and formed the tsunami.
When waves hit the coasts of countries bordering the Indian
Ocean, they were up to 100 feet tall. In some areas the waves
penetrated to two miles inland, displacing about 1.7 million
people. The tsunami was detected as far away as South Af-
rica (almost 5,300 miles away) and even registered in Ant-
arctica, where disturbances in the water level were detected
for several days afterward.
1

2. SUMATRA (continued)
On the Richter Scale, the Sumatra earthquake registered a 9.1,
which means that 109.1 joules of energy were released. The am-
plitude of this intensity is 105.1 centimeters.
Earthquake
Response
In many parts of the
world, it is very diffi-
cult for governments
to get help to areas
affected by earth-
quakes because of lack
of funding. In both
the Indian and Haitian
earthquakes, humani-
tarian aid played a
large part in getting
civilians supplies and
places to live after the
event. After the earth-
Epicenter of the Sumatra earthquake, and other affected areas
quake that devastated (Natural Resources Canada)
India, roughly $7 bil-
lion was donated from
around the world for
the relief efforts, and
HAITI
many generous contri- Another terrible earthquake devastated Haiti early this year.
butions were also The magnitude-7.0 quake hit just west of the national capi-
made to help people
tal, Port-au-Prince, in the late afternoon on January 10,
affected by the Haiti
2010. It was estimated that over three million people were
earthquake.
affected: about 222,000 people were killed and over one mil-
lion left homeless, with countless others injured.
2

3. HAITI (CONTINUED)
1.0x107 joules of energy were released in this earthquake,
and the amplitude of the intensity of the quake was
1.0x103 centimeters.
The region of the Caribbean in which Haiti is located is
known for its seismic activity; in 1770 an earthquake de-
stroyed the entire city of Port-au-Prince, according to eye-
Relief Efforts witnesses, and in 1946 an earthquake in the neighboring
In Haiti
Dominican Republic produced tsunamis that killed over a
Following the earthquake, thousand people. In addition to seismic activity, this part
the entire country of of the world is also prone to extreme weather conditions
Haiti was left without
electricity or land-line such as cyclones and hurricanes.
telephones. This was the
most severe seismic event
that had hit Haiti in over
200 years.
There were several obsta-
cles that prevented relief
agencies from getting aid
to Haiti quickly. The
main ports of Haiti had
been so devastated by the
quake that it was very
difficult to move supplies
into the cities quickly.
The airport also was Epicenter of the 2010 Haiti Earthquake
barely functional, and Sciencebase.com
roads were often blocked
by debris and wandering
people who had lost their
COMPARISON
homes. The weak central Although the Sumatra earthquake was one-and-a-half
government of Haiti re-
mains an issue today.: times as powerful as the Haiti earthquake, the numbers of
many of its departments fatalities and people relocated were quite similar. This is
were not functioning for because the population density is almost four times as
months afterward, and it
was very difficult for the high in Haiti as it is in Sumatra.
officials who remained to
manage the debris re- If the intensities of both earthquakes were increased by
moval and recovery ef-
forts. 20%, the Richter number for the earthquakes would be 7.1
for Haiti and 9.2 for Sumatra.
3

4. SEISMOLOGY:
MEASURING THE WORLD’S EARTHQUAKES
The tools used to measure seismic activity are known generally
as seismographs. Seismographs typically work by using an in-
ternal weight to record the motion of the ground during an
The History of
earthquake, and from this the intensity of the earthquake and
Seismographs the amplitude of the vibration of the crust’s surface can be cal-
culated.
Although the first seis-
mographs were invented
in the first and second
Seismographic devices are extremely sensitive to the slightest
centuries A.D., seismol- vibrations in the earth’s crust, so they are susceptible to
ogy did not mature as a “pollution”: picking up vibrations that are caused by passing
scientific field until al- trains, for example. To prevent this, seismographs are often
most the twentieth cen- connected to bedrock, so that the only vibrations that will reg-
tury. Early seismo- ister are the vibrations of the rock.
graphs, known as
“seismoscopes”, were
devices that were only
capable of registering an
earthquake, not of deter-
mining how powerful it
was. In the late 1800’s
and early 1900’s, how-
ever, several break-
throughs allowed seis-
mology to gain scientific
standing: among other
things, improved seis-
mograph designs and Seismograph-generated illustration of seismic activity vs. time
(University of Sydney)
the work of Charles
Richter were important
The mathematical theory behind seismology was not fully real-
factors that made the
ized until 1935, when Charles Francis Richter developed a
quantifying of seismic
scale for measuring the intensity of earthquakes. It was the
energy into a scientific
process.
first scale to be based on calculations of the amplitude of an
earthquake’s intensity in centimeters; earlier scales had meas-
ured damage in terms of number of people affected.
4

5. SEISMOLOGY (continued)
The Richter number for an earthquake is determined by a loga-
rithmic formula,
I
R = log I0
where I is the intensity of the earthquake and I0 is a standard
earthquake intensity of the amplitude 10-4 centimeters.
Magnitudes Description Effects
Less than 2.0 Micro Not felt
The Richter Scale
2.0-2.9 Minor Felt but not recorded
The Richter magni-
tude scale assigns a 3.0-3.9 Minor Felt but not recorded
single number to
quantify the amount 4.0-4.9 Light Noticeable shaking
of seismic energy re- and rattling
leased by an earth-
5.0-5.9 Moderate Can cause damage to
quake. This table de- poorly-designed
scribes typical effects structures
based on Richter num-
6.0-6.9 Strong Can be destructive in
bers. populated areas
7.0-7.9 Major Can cause serious
damage over large
areas
8.0-8.9 Great Can cause serious
damage over several
hundred miles across
9.0-9.9 Great Devastating thou-
sands of miles across
10+ Epic Never recorded
The amount of energy released by an earthquake is given by the
formula
E = 10 R
where “R” represents the Richter number of the earthquake.
5

6. SOLVING SEISMOLOGY PROBLEMS
To determine what the intensity of an earthquake would be if it
were increased by 20%, given only the Richter number of the
earthquake, a researcher must first find the intensity of the
earthquake (the value “I”, in centimeters), multiply this number
by 120%, then find the Richter number for the more powerful
earthquake.
Charles Richter
(1900 - 1985) In the Sumatra earthquake, for example, the Richter number
was 9.1.
I
9.1 = log
10-4
Finding the intensity of 9.1 = log I - log 10-4
the earthquake by solv-
ing the logarithmic 9.1 = log I - (-4)
equation for I. “I ini- 9.1 = log I + 4
tial” is defined as an
intensity of 10^-4 cen- 5.1 = log I
timeters, the lower limit
Charles Richter, the de- of seismic perception I = 105.1
veloper of the Richter for humans.
scale, was born in Hamil-
Multiply by 1.2 to find
ton, Ohio, in 1900. He 120% of the value
105.1 • 1.2 = 151071.0494
studied at the University
of Southern California
and Stanford University, Use the new earth-
151071.0494
Rnew = log
and he completed his quake’s intensity to 10-4
doctorate at the Califor- calculate its Richter
nia Institute of Technol- number.
ogy, where he later re-
Rnew = 9.1792
turned as a professor of
seismology. Richter de-
veloped his famous seis- When the intensity of the earthquake was increased by 20%, the
mic scale in 1935, the first
scientifically-viable sys-
Richter number increased by only about eight hundredths of a
tem for categorizing unit. This is because of the logarithmic nature of the scale: an
earthquakes. The scale earthquake that registers a 9.0 is ten times as powerful as one
was a breakthrough in
quantifying the amount that registers an 8.0.
of seismic energy that
occurs during quakes.
6

7. WORKS CITED
Sumatra Earthquake
Information:
http://www.tectonics.caltech.edu/outreach/highlights/
sumatra/what.html
Image:
http://atlas.nrcan.gc.ca/site/english/maps/
environment/naturalhazards/tsunami/
fig9_tsunami_sumatra.jpg
Haiti Earthquake
Information:
http://www.nytimes.com/info/haiti-earthquake-2010/
http://www.sciencebase.com/2010-haiti-
earthquake.html
Image:
http://www.sciencebase.com/images/2010-haiti-e
arthquake.png
Seismographs
Information:
http://science.howstuffworks.com/environmental/
earth/geophysics/question142.htm
http://earthquake.usgs.gov/learn/topics/seismology/
history/part01.php
Image:
http://sydney.edu.au/science/uniserve_science/school/
Seismograph/seismogram.jpg
Richter Scale and Table
Table:
http://en.wikipedia.org/wiki/Richter_magnitude_scale
Richter Information
Information:
http://www.cartage.org.lb/en/themes/biographies/
MainBiographies/R/RichterC/1.html
Image:
http://i2.squidoocdn.com/resize/squidoo_images/250/
draft_lens1950170module9167283photo_120852412315
0px-CharlesRichter.jpg
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