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Images


AP Photo

Click for before and after photos

P + S Time-Travel Graph from the N.Y.S. Earth Science Reference Tables

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Epicenter Location

Tectonic Map

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Steve's Tsuanami Warning Photo

The Great Sumatra Earthquake and Tsunami of December 2004
A Comprehensive Inquiry Based Classroom Exercise for High School Students
David Robison and Steve Kluge


Introduction

The incredible media coverage of the Sumatra Earthquake and Tsunami of December 26, 2004, provided the world with images provoking both incredible sadness at the tragic loss of life, and awe at the destructive release of energy from one brief convulsion of Earth’s crust. Earth scientists everywhere were eager to study the earthquake that rattled the entire planet and generated the tsunami that destroyed so much on the rim of the Indian Ocean basin. As earth science teachers, we viewed the event as a teachable moment ripe with possibilities.

The relationship between the underlying geologic processes and the day-to-day lives of people was made instantly, obviously, and painfully clear. Here was an opportunity for our students to see firsthand the importance of earth scientists’ efforts to understand and perhaps eventually predict the workings of the earth system. The ignorance of those happy but oblivious beachgoers who followed the receding sea before the arrival of the waves, and the story of the young girl who had learned the significance of such a recession (and saved many lives by warning others to leave the beach) drove home the value of personal understanding and preparedness. The irony of the instantaneous appearance of images and videos of the destruction juxtaposed with the lack of warning to people who might have had hours to prepare, illustrated the fact that technology is limited by how effectively it is employed. Armed with actual data related to a real, familiar event, we would introduce our students to a number of concepts in seismology and plate tectonics, through thoughtful and careful analysis.


Creating the Activity

Shortly after the quake, we downloaded a number of maps and original seismograms using the Global Earthquake Explorer1 (GEE, http://www.seis.sc.edu/gee/) , and found that working out the epicenter location and origin time from the seismograms yielded remarkably accurate results. From there on, we each worked in tandem, developing additional activities and supporting materials (web links, images, and our own web pages) that would introduce or reinforce understandings of the geologic principles involved and the connection between that science, technology and the lives of everyday people. In a steady stream of emails each built upon the other’s ideas, this comprehensive classroom exercise achieved its present form.

The activity consists of the following sections;

  • Part 1 - Students analyze actual seismograms, calculate P and S wave travel time differences, and determine the corresponding epicenter distances. This information is recorded in table form on the exercise. Using the data, students then plot the epicenter distances on a map and determine the epicenter location, and work backwards to determine the origin time of the quake. Students that are careful every step of the way will be rewarded with a very accurate, pinpoint location of the epicenter on their maps, and origin times within a few seconds of the actual time. Questions accompanying Part 1 lead students to examination the nature of the plate boundary east of Indonesia, including the study of maps and cross sections, web resources provided by the USGS, as well as original material developed for this exercise.
  • Part 2 - Skills and concepts developed in Part 1 are reinforced as students look analyze additional seismograms and plot the epicenter location on a larger scale map.
  • Part 3 - Students study the nature of tsunamis, and determine and map the location of the advancing waves over a period of several hours.
  • Part 4 - Students determine the average velocity of seismic waves that have traveled various distances, and are asked to reflect on the reasons for the observed differences. This final activity provides an excellent anticipatory set for teachers wishing to further explore the nature of the earth’s interior and the how that nature is revealed by interpreting the propagation of seismic waves.
  • Part 5 - Contains a number of concluding questions that require students to search for information regarding the human impact of the event. They view several videos and still images, and are asked to review their data and explore ways in which various locations might have been spared some of the enormous loss of life.

Our downloadable exercise includes seismograms, maps, seismic wave travel time charts, and a world tectonic map customized for the Indian Ocean basin.


Download this Tsunami Earthquake lab


Reflecting on the Activity

To date, this lab has been used with hundreds of students. If anecdotal reports form teachers are accurate, the results have been outstanding. Teachers have noted the enthusiasm with which students have approached the lab, and are happy with the concepts the the students retain. The breadth of the lab provided several “kick off” points for additional discussions and study of plate tectonics; the examination of the distance volcanoes are from the surface expression of the plate boundary, the depth to which a plate must dive before magma is generated, and earthquakes produced by the rising magma.

Plotting tsunami travel times, watching associated videos, and discussing who had a chance to get out of the way (and even what "out of the way" means) brought the relationship between day-to-day human activity and the abstract idea of subducting plates into clear focus for our students. Taking it a step farther, we've been able to discuss the similarities and differences in the Pacific Northwest of the US, illustrating it all with EPODS (Earth Science Picture of the Day, http://epod.usra.edu/), recent articles regarding hazards of the Pacific Northwest and personal photos and anecdotes.

For years, high school earth science students have used artificial or doctored seismograms to plot earthquakes that as far as they’re concerned may or may not have ever happened. These ‘quakes’ have no real connection to their lives, and as such the activity often devolves into the mere acquisition of a skill. What has impressed us with our activity is how students who work carefully can so accurately plot the position and calculate the origin time of a very real and current earthquake using real, un-doctored data and a simple travel time graph that has been part of the NYS earth science reference tables for 35 years.


Additional Data: You can have your students double check their results or create a version of the lab yourself by using the information below.
All of the following seismograms were made using the GEE software with the help and special thanks to Michael Hubenthal (Education Specialist, IRIS Consortium). Some of these seismograms do not have the P and S waves flagged in case you would like to test their ability to distinguish the wave types. We would also like to thank Dr. Bryce M. Hand (Emeritus Professor of Geology, Syracuse University) for his assistance with tsunami wave propagation in the Indian Ocean.

We recommend using the GEE (Global Earthquake Explorer) software to download seismograms for yourself or to see real time earthquake data. They also have great interactive tutorials.


Part 1) Finding the epicenter: Pick the stations and maps that you wish.

Intermediate Stations:

Seismograph Stations
(Click for links to the stations)
Unflagged Seismograms
(click to open)
Flagged Seismograms
(click to open)
Map
(click to open)
IC.LSA (Tibet, China)
(29.7 N, 91.2 E)
KMBO (Mbogo, Kenya)
(1.1 S, 37.25 E)
GUMO - Guam, Mariana Is.
(13.59 N, 144.87 E)

Closest stations to the epicenter: It is impossible to differentiate the P and S wave signatures in these stations but being so close to the epicenter there is less map distortion.

Seismograph Stations
(Click for links to the stations)
Unflagged Seismograms
(click to open)
Flagged Seismograms
(click to open)
Map
(click to open)
COCO, Cocos Is., Australia
(12.2° S, 96.8° E)
PALK, Pallekele, Sri Lanka
(7.3° N, 80.7° E)
DGAR, Diego Garcia,
(7.4° S, 72.5° E)

Farthest stations from the epicenter: It is easiest to see the P and S waves at these stations but there is much more map distortion. Print out these seismograms and the map yourself to help students figure out the reason for this distortion.
Using a globe would minimize this distortion.

Seismograph Stations
(Click for links to the stations)
Unflagged Seismograms
(click to open)
Flagged Seismograms
(click to open)
Map
(click to open)
II.ARU - Arti, Russia
(56.4 N, 58.6 E)

Circles on a flat map
(pdf)

IU.LSZ - Lusaka, Zambia
(15.3 S, 28.2 E)
IU.SNZO - Karori, New Zealand
(41.3 S, 174.7 E)

About the authors

Steve and David are earth science teachers employed at opposite ends of New York State. They met ‘electronically’ a few years ago as contributing members of the SUNY College at Oneonta sponsored ESPRIT listserv – an online community of primarily high school level earth science educators and university and private sector earth scientists (http://external.oneonta.edu/mentor/listserv.html) dedicated to sharing and disseminating materials, ideas, and methods among the earth science education community. They both maintain their own extensive websites at their respective schools (Steve’s at http://www.bedford.k12.ny.us/flhs/science/geohome.html and David’s at http://www.regentsearthscience.com. David also maintains a separate site of teaching resources at his “Share-a-thon” site at http://www.regentsearthscience.com/webshare/) and both are trained DLESE ambassadors. They have collaborated on smaller activities in the past, notably on a lunar eclipse viewing activity that was done by several thousand students across New York State last October.


Contact the authors: David Robison and Steve Kluge

3/2005