Locating Regional Seismic Events Using the Indiana

PEPP Seismic Network

 

Greg Small, Harrison High School, Evansville, Indiana.

 

Purpose:        

 

            Implementation of a project developed during the PEPP Summer Workshop at Indiana University to better enable local PEPP participants to quickly and accurately locate the origins of local seismic events.

 

Background:  

 

            Over the past two years we have experienced four earthquakes in the tri-county area ranging from about 2.0 to 4.0 on the Richter Scale.  The most recent quake this past December was within fifteen miles of our school.  It registered 4.0 and was felt throughout the area.  Our local Emergency Management Agency was aware that we had a PEPP seismometer and contacted us almost immediately to find out where they should respond.  With only a single component seismometer and no way to obtain data from other network stations, we were of limited assistance.

 

Project Description:

 

            At the PEPP workshop this summer, certain participants developed a project with Harrison High School, New Harmony High School and Perry Central Jr/Sr High School to use each school’s PEPP instruments to watch for seismic events generated by local surface coal mines when they blast overburden rock.  These events generate a distinctive seismic wave and are easy to spot on our PEPP seismometers. It is our goal to use the collected information regarding such blasts to enable us to quickly locate the origins of other local seismic events.

 

Description of Lesson:

 

1. Each participating school has already received a detailed map of active   surface mines of Southwestern Indiana provided by the Indiana Geological Survey.              Teachers and students will become familiar with the map and practice calculating distance in kilometers from their school to some of the active mine sites.

 

2. After consulting with Black Beauty Coal Company geologists, they have agreed to advise us of the approximate time and location of their blast.

 

3. Each of the participating high schools will set up a “watch time” during   which students will monitor their school’s seismometer for the local blast and record the exact arrival time.

 

4. Following the blast, all of the participating schools will communicate using video conferencing or e-mail in order to compare data gathered during the watch time and to contact the coal company geologist to determine the time the blast was detonated (“the origin time”).

 

5. Students at each school will then use the origin time and arrival time data to determine the distance from the blast and their school.  With the data shared between the participating schools, the students will triangulate the calculated distances to determine the location of origin.

 

6. Each school will compare the results with the other schools to determine how accurately we can pinpoint location.

           

7. At the conclusion of the project, each student will submit a report on how their team was able to use data from the PEPP network to accurately determine the location of origin for a specific seismic event.

 

Indiana State Standards:

 

The Indiana Academic Standards for 2000 include a variety of standards in Earth Science Physics and Physical Science which are addressed in this project.  They are as follows:

           

     P.1.22. Describe waves in terms of their fundamental characteristics of velocity, wavelength, frequency or period, and amplitude.  Know that radio waves, light, and X-rays are different wavelength bands in the spectrum of the electromagnetic waves, whose speed in a vacuum is approximately 3 X 10³  m/s (186,000 miles/second).

 

            P.1.23.  Use the principle of superposition to describe the interference effects arising from propagation of several waves through the same medium.  

 

            P.1.24.  Use the concepts of reflection, refraction, polarization, transmission, and absorption to predict the motion of waves moving through space and matter. 

 

            P.1.25.  Use the concepts of wave motion to predict conceptually and quantitatively the various properties of a simple optical system.

 

            CP.1.21.  Understand and explain that the change in motion of an object (acceleration) is proportional to the net force applied to the object and inversely proportional to the object’s mass. (a=F/m)

 

            CP.1.22.  Recognize and explain that whenever one object exerts a force on another, and equal and opposite force is exerted back on it by the other object.

 

            CP.1.23.  Understand and explain that the motion of an object is described < by its position, velocity, and acceleration.

 

            CP.1.24.  Recognize and explain that waves are described by their velocity, wavelength, frequency or period, and amplitude.

 

            CP.1.25.  Understand and explain that waves can superpose on one another, bend around corners, reflect off surfaces, be absorbed by materials they enter, and change direction when entering a new material.

 

            CP.1.26.  Realize and explain that all motion is relative to whatever frame or reference is chosen, for there is no absolute motionless frame from which to judge all motion.

 

            ES.1.23.  Explain motions, transformations, and locations of materials in the Earth’s lithosphere and interior.  For example, describe the movement of the plates that make up the crust of the earth and the resulting formation of earthquakes, volcanoes, trenches and mountains.

 

            ES.1.24.  Understand and discuss continental drift, sea-floor spreading, and plate tectonics.  Include evidence that supports the movement of the plates such as magnetic stripes on the ocean floor, fossil evidence on separate continents, and the continuity of geological features.

 

            ES.1.29.  Recognize and explain that in geologic change, the present arises from the materials of the past and in ways that can be explained according to the same physical and chemical laws.

 

Conclusion

 

            By participating in this project, the faculty and students will grasp a better understanding of the PEPP instruments and local seismic events.  Moreover, the ability to pinpoint origins of local seismic happenings will be of assistance to the local Emergency Management Agency in the event of a major seismic occurrence.