Earthquakes and GIS
Antoinette Mastropieri
EM SC 100S: Exploring Real and Virtual Environments
Dr. Donna Peuquet
September 21, 2011
In today’s world geographic information systems or GIS have become increasingly
important. They not only have a wide range of uses – such as disease mapping or storm tracking
– but are also accessible to the general public (Couclelis, AccessScience). With the recent
earthquakes in Virginia and Alaska, it is easy to see why tracking tectonic movements have
become essential to seismologists, or those who study earthquakes. They want to and need to see
when and which plates are moving and to warn surrounding areas if an earthquake may occur.
Over the past fifteen years the technology used to track tectonic movements has grown
exponentially, becoming more precise and advanced (Kwan, AccessScience). Because of this,
seismologists can see the different types of fault boundaries, record the energy releases from
underground, and create hazard maps and predictions for earthquakes.
In relation to earthquakes, GIS show the fault lines of plate boundaries, assist in making
hazard maps, and create shake maps showing where the most damage occurred (USGS,
Earthquake Hazards Program). According to Michael Kennedy, a Geographic Information
System is “an organized collection of computer hardware and software, people, money, and
organizational infrastructure that makes possible the acquisition and storage of geographic and
related attribute data, for purposes of retrieval, analysis, synthesis, and display to promote
understanding and assist decision making,” (Kennedy, Introducing Geographic Information
Systems with ArcGIS). GIS can even create prediction maps showing, if there was an earthquake,
which places would be hit the hardest (USGS, Earthquake Hazards Program).
An earthquake is essentially “the sudden movement of the Earth’s plates releasing strain
along the fault line,” (Scholz and Shedlock, AccessScience). The energy dissipated from this
movement varies, but each earthquake sends out seismic waves that travel through the Earth,
causing shakes (Scholz and Shedlock, AccessScience). Earthquakes are measured according to
the what is known as the Richter Scale – in actuality the Moment Magnitude Scale – in which
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each increment is a power of ten (USGS, USGS Magnitude Policy). The higher the earthquake’s
rating, the stronger magnitude the earthquake has. The United States Geological Survey states
that “the magnitude of an earthquake is a measured value of the earthquake size,” whereas “the
intensity of an earthquake is a measure of the shaking created by the earthquake, and this
value…var[ies] with location” (USGS, Earthquake Hazards Program). Although an earthquake
may only last for a few seconds, seismograms – the instruments that measure earthquakes –
“illustrate that…motion is recorded all over the Earth for hours, and even days after an
earthquake,” (Scholz and Shedlock, AccessScience).
The Ring of Fire is where “approximately 90% of all earthquakes occur,” (Scholz and
Shedlock, AccessScience). In general the plates themselves move quite slowly – only a few
centimeters per year – but they are always in motion (Scholz and Shedlock, AccessScience).
Source: Scholz, Christopher H., and Kaye M. Shedlock. "Earthquake." AccessScience.
McGraw-Hill Companies, 2008. Web. 5 Sept. 2011. <http://www.accessscience.com.
ezaccess.libraries.psu.edu/content.aspx?searchStr=earthquake&id=209800>.
There are various sizes of plates along the Earth’s crust, but the largest include the North
American plate, the Pacific plate, and the Indo-European plate (Pitman and Van Huene,
AccessScience). The main plates mostly follow continent boundaries, but there are some
instances when earthquakes occur in the interplate (Pitman and Van Huene, AccessScience).
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Earthquakes occur at a fault line (Scholz and Shedlock, AccessScience), which is why
seismologists would want to look at fault lines to see not only what type of fault
exists but also to understand how quickly the plates that create the fault are moving. One
particular application provided through GIS is a fault map, which shows where the fault lines are
located and how old they are.
Source: EHP Quaternary Faults. Map. Geologic Hazards Science Center. United States
Geological Survey, 20 July 2011. Web. 6 Sept. 2011.<http://geohazards.usgs.gov/
qfaults/map.php>.
The USGS estimates that several million earthquakes occur in the world each year, but
that many go undetected because they hit remote areas or have very small magnitudes (USGS,
Earthquake Facts and Statistics).
Source: "Latest Earthquakes." Map. Earthquake Hazards Program. United States Geological
Survey, 6 Sept. 2011. Web. 6 Sept. 2011. <http://earthquake.usgs.gov/earthquakes/mapping.>
There are several GIS enhanced maps found on the USGS website that show when and where
earthquakes have occurred. In particular one entitled “Latest Earthquakes” is an up-to-date map
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showing where earthquakes have most recently hit. One can even report an earthquake with this
map or on another one entitled “Did You Feel It?” (USGS, Earthquake Hazards Program).
Preventative measures can be taken from the data that seismologists collect through GIS.
The USGS creates hazard maps that show the intensity of an earthquake and the locations where
the earthquake will hit the most (USGS, Earthquake Hazards Program).
Source: "2008 United States National Seismic Hazard Maps." Map. Earthquake Hazards
Program. United States Geological Survey, 9 Mar. 2011. Web. 5 Sept. 2011.
<http://earthquake.usgs.gov/hazards/products/conterminous/2008/>.
Hazard maps are extremely useful because one can insert any magnitude into the program in any
location and see what the damage will be. These maps “display earthquake ground motions for
various probability levels across the United States and are applied in seismic provisions of
building codes, insurance rate structures, risk assessments, and other public policy,” (USGS,
Earthquake Hazard Program).
Additionally, shake maps are produced through GIS after an earthquake to show where
intensity was the highest. The USGS maps “provide near-real-time maps of ground motion and
shaking intensity following significant earthquakes,” (USGS, Earthquake Hazards Program).
These maps have several uses including post-earthquake response and recovery, public and
scientific information, and disaster planning (USGS, Earthquake Hazards Program).
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Source: "Shakemap of Reno, Nevada on August 17, 2011." Map. Earthquake Hazards Program.
United States Geological Survey, 17 Aug. 2011. Web. 6 Sept. 2011. <http://earthquake.usgs.gov/
earthquakes/shakemap/nn/shake/2011229_345424/>.
Furthermore, the USGS has several software creators that have made programs to track
the movement of fault lines and the strength of each particular fault line. One such software
allows the user to pick a fault line and then find how a certain chosen point would be affected by
an earthquake.
Source: "3D Visualization of Earthquake Focal Mechanisms Using ArcScene." Map. Western
Earthquakes Hazard Program. United States Geological Survey, 17 Dec. 2007. Web. 5 Sept.
2011. http://pubs.usgs.gov/ds/2007/241/.
Personally, the use of GIS for earthquake tracking is extremely interesting. I find it
fascinating that seismologists are able to locate a fault and then produce hazard maps. Although
the system is not yet perfected, it is comforting to know that scientists are working hard to
protect us. I would rather be prepared for an earthquake that never occurs than be unprepared for
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an earthquake that strikes without warning. Because of the work seismologists are doing and the
capabilities GIS has given them it is hard to believe that only a few decades ago, technology was
not as advanced.
Clearly, there are numerous positives to the use of GIS in tectonic movements. GIS create
various maps, including hazard and shake maps. In addition, GIS help seismologists to track
fault lines in both 2D and 3D settings. Furthermore, GIS allow anyone to update the United
States Geological Survey as to when and where an earthquake occurred. GIS also give everyday
people the chance to look at various softwares to see different points on a fault line that may
cause the most problems. Finally, GIS allow seismologists to predict the effects of an earthquake
and this can be forwarded to the government to establish safe building codes.
However, there are some negatives to the use of GIS in tectonic movements as well. The
earthquake data that has been collected does not contain all of the earthquakes that have
happened. This means that tracking technology is not available everywhere so seismologists are
not able to record earthquakes in these locations. Another negative is that earthquake prediction
is somewhat risky because sometimes the Earth sends out signals like that before an earthquake
and one does not occur, or there are no signals sent out, but an earthquake does occur. Even
though seismologists are not exactly sure when an earthquake could happen, they can make sure
that people are educated about what to do in an earthquake and ways to make locations safer for
everyone. Finally, so many earthquakes occur that hazard maps and shake maps are more used as
preventative measures before an earthquake rather than during a disaster.
As Jeffrey Kluger wrote after the devastating earthquake in Haiti, “For now, the best the
USGS…can do is use the global web of seismometers and other instruments that are already in
place and always being improved to build the best map possible of the planet's interior,” (Kluger,
Time). Through this data collection, seismologists can somewhat predict how severe the next
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tremor will be and create a multitude of technologies and maps using GIS. GIS in relation to
earthquakes is extremely useful to everyone and it is through GIS that we can learn more about
Earth and the tremors that it makes.
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Works Cited
“3D Visualization of Earthquake Focal Mechanisms Using ArcScene.”Map.Western
Earthquakes Hazard Program. United States Geological Survey, 17 Dec. 2007. Web. 5
Sept. 2011. <http://pubs.usgs.gov/ds/2007/241/>.
Couclelis, Helen. “Geographic Information Systems.”AccessScience. McGraw-Hill Companies,
2008. Web. 5 Sept. 2011. <http://www.accessscience.com.ezaccess.libraries.psu.edu/
content.aspx?searchStr=Geographic+information+systems&id=757430>.
“Did You Feel It?” Map. Earthquake Hazards Program. United States Geological Survey, 6
Sept. 2011. Web. 6 Sept. 2011. <http://earthquake.usgs.gov/earthquakes/dyfi/>.
“Earthquake Density Maps for the United States.” Map. Earthquake Hazards Program. United
States Geological Survey, 29 Oct. 2009. Web. 6 Sept. 2011. <http://earthquake.usgs.gov/
earthquakes/states/us_density.php>.
EHP Quaternary Faults. Map. Geologic Hazards Science Center. United States Geological
Survey, 20 July 2011. Web. 6 Sept. 2011. <http://geohazards.usgs.gov/qfaults/map.php>.
Kennedy, Michael. Introducing Geographic Information Systems with ArcGIS. Hoboken, New
Jersey: John Wiley and Sons, 2006. Print.
Kluger, Jeffrey. “Could the Haiti Earthquake Have Been Predicted?” Time Magazine. N.p., 13
Jan. 2010. Web. 5 Sept. 2011. <http://www.time.com/time/health/article/
0,8599,1953347,00.html>.
Kwan, Mei-Po. “Three-dimensional Geographic Information Systems.”AccessScience. McGrawHill Inc., 2011. Web. 6 Sept. 2011. <http://www.accessscience.com.ezaccess.libraries.
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psu.edu/content.aspx?searchStr=Geographic+information+systems&id=YB110003>.
“Latest Earthquakes.” Map. Earthquake Hazards Program. United States Geological Survey, 6
Sept. 2011. Web. 6 Sept. 2011. <http://earthquake.usgs.gov/earthquakes/mapping/>.
Pitman III, Walter C., and Roland Van Huene.“Plate Tectonics.” AccessScience. McGraw-Hill,
2008.Web. 7 Sept. 2011. <http://www.accessscience.com.ezaccess.libraries.psu.edu/
content.aspx?searchStr=plate+tectonics&id=527000>.
Scholz, Christopher H., and Kaye M. Shedlock. “Earthquake.” AccessScience. McGraw-Hill
Companies, 2008. Web. 5 Sept. 2011. <http://www.accessscience.com.ezaccess.libraries.
psu.edu/content.aspx?searchStr=earthquake&id=209800>.
“Shakemap of Reno, Nevada on August 17, 2011.” Map. Earthquake Hazards Program. United States
Geological Survey, 17 Aug. 2011. Web. 6 Sept. 2011. <http://earthquake.usgs.gov/earthquakes/
shakemap/nn/shake/2011229_345424/>.
“2008 United States National Seismic Hazard Maps.” Map. Earthquake Hazards Program. United States
Geological Survey, 9 Mar. 2011. Web. 5 Sept. 2011. <http://earthquake.usgs.gov/hazards/
products/conterminous/2008/>.
United States Geological Survey. “Earthquake Facts and Statistics.” Earthquake Hazards
Program. United States Geological Survey, 11 July 2011. Web. 5 Sept. 2011.
<http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php>.
- - -. “USGS Magnitude Policy.” Earthquake Hazards Program. United States Geological
Survey, 12 July 2011. Web. 5 Sept. 2011. <http://earthquake.usgs.gov/aboutus/docs/
020204mag_policy.php>.
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