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Mt.Pinatubo
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ERT Log

Graph Mt. Pinatubo

This activity will help you practice valuable graphing skills which are necessary to being an Emergency Response Team member.

Beginning in May and throughout June, scientists collected seismic data on Mt. Pinatubo. Use this data to create three line graphs. You will need graph paper, a pencil and a ruler.

  • On the "y" axis create a scale from 0 to 2000 and label this axis, "Total Number of Events."
  • On the "x" axis, create a scale with 32 marks. List the dates upon which the events were recorded and label this axis, "Date." The dates go from May 16 to June 16 (32 days)
  • Above each date place a dot for the number of events recorded on that day. Above 21-May-1991 on the "x" axis, for instance, put a dot across from 144 on the "y" axis. Plot all the data. Connect the dots.

You can download the Excel® version of this data to create a graph in Microsoft® Excel.

Date

Total Number of Events

Observation Log

16-May-91

53

 

17-May-91

49

 

18-May-91

38

 

19-May-91

98

Steam clouds

20-May-91

120

Series of small hydrothermal "burps"

21-May-91

144

Small hydrothermal explosion; steam clouds and small amounts of tephra ejected 300 to 500 meters 

22-May-91

88

 

23-May-91

66

 

24-May-91

78

 

25-May-91

92

 

26-May-91

134

Small amounts of tephra ejected 100-200 meters

27-May-91

34

 

28-May-91

89

 

29-May-91

92

 

30-May-91

101

 

31-May-91

61

 

1-Jun-91

89

 

2-Jun-91

94

 

3-Jun-91

135

Ash ejection lasting for 30 minutes

4-Jun-91

156

Ash ejections

5-Jun-91

167

 

6-Jun-91

178

 

7-Jun-91

1500

Low frequency volcanic quakes; magma nearing the surface

8-Jun-91

1776

Explosion-type earthquake

9-Jun-91

1895

Violent eruption; pyroclastic flows to 5 kilometers

10-Jun-91

685

 

11-Jun-91

1203

Harmonic tremors

12-Jun-91

1565

Intense seismic activity and explosions followed by 3 major explosions, ash, pumice, and ejected fragments

13-Jun-91

1706

Violent eruption triggering heavy ashfalls

14-Jun-91

1905

Fourth major eruption; vertical ash cloud 25 kilometers; pyroclastic flows 15 kilometers from source

15-Jun-91

1843

Two explosions, pyroclastic flows moving between 70 to 80 km/hr; vertical ash cloud 40km high

16-Jun-91

856

Activities decline both in frequency and magnitude

1. Looking at this data over the weeks, pay attention to the peaks and valleys in the line graph. Is there a pattern? What does the pattern or lack of pattern tell you about how hard it is to predict volcanic eruptions?

2. Read the observation log for these times and write notes on your graph about what was observed. On your graph, circle some of the peaks where the seismic activity was followed by observations of volcanic activity.