Nancy R. Martin

8/28/00

Physical Science

Investigating Quarry Blasts

Contributed by Nancy Martin, Bloomington H.S. North

Rationale:

Students apply their skills in identifying patterns (shape, symmetry, etc...) found in wave forms to determine if a seismogram represents a small earthquake or quarry blast.

Objectives:

Students will:

• Categorize wave forms by shape, symmetry, duration, time of day, etc...

• Interpret seismograms to develop a strategy to identify which wave forms represent small earthquakes vs. quarry blasts.

Introduction:

Bloomington Indiana is located in limestone country and many of the small "earthquake like" wave forms registered by our seismometer are quarry blasts. This exercise allows the student to use and develop their skills in pattern recognition, categorization, and interpretation to develop a strategy/hypothesis.

Materials: (for each group of two persons)

• -2 sets of seismographs of small earthquakes/quarry blasts.
• -Tracing paper
• -Ruler
• -Paper and pencil
• -2 sets of quarry blasting schedules.

Procedures:

Part 1:

• Study the first set of seismograph records and trace the outer shape of the wave forms.
• Record the day of the week and time of each seismograph record.
• Categorize the tracings by shape, symmetry and time of day. Record the information in a data table.
• Repeat steps 1 thru 3 for all of the available seismographs.
• Compare the information to the available quarry blasting schedule.
• Separate the small earthquakes from the quarry blasts.

Conclusions: (part 1)

• What are the differences between the shape, symmetry and time of day for small earthquakes and quarry blasts?

• Create a strategy to identify quarry blasts from small earthquakes.

Procedures:

Part 2:

• Repeats steps 1-4 for the second set of seismographs.
• Apply your strategy for determining if this wave form is a quarry blast.
• Verify your results to the second quarry blast schedule.

Conclusions: (part 2)

• Is it possible to identify the quarry blasts without the blasting schedule?

• Describe how well your strategy worked in identifying quarry blasts.

• What are the problems encountered while developing your strategy?

• What adjustments should you make to your strategy or collection of data?

Possible Extension Activities:

• Do a collaborative evaluation of events with another school in southern Indiana and compare seismographs for the same events. Try to determine which quarry is the origin of the blasts and the distance the blasts waves travel.

• Do a study over time (months) of quarry blasts wave forms. This might work as a science fair project. Enlist the help of limestone quarries to provide information.