# Activity 1- Past eruptions

To try and prepare for what could be about to happen, geologists on the island have been reviewing the ash volumes from previous eruptions.

Professor Si Smology from the University of FitzRoy is the foremost expert on volcanic activity on Green Island. He's currently mapping where ash fell across the island in the last four eruptions, but with the rumblings becoming more and more frequent, I think he could use a hand filling in the table as quickly as possible! Help him fill in the blanks in the table on your worksheet, there are some tips below in case you get stuck.

Eruption yearArea covered (km2)Area covered (m2)Depth of ash (mm)Depth of ash (m)Volume of ash  (m3)Volume of ash (millions of m3)Eruption height (km)
18101100509.0
165190154.0
1278400306.5
86320258.0
• Hint: convert area from km2 to m2 using 1 km2 = 1,000,000 m2
• Hint: convert depth from mm to m using 1 mm = 0.001 m
• Hint: volume (m3) = area (m2) x depth (m)
• Hint: convert volume in m3 to millions of m3 by dividing by 1,000,000
• Hint: one million = 1,000,000

Using the graph on page 2 of your worksheet, plot volume of ash on the x-axis against eruption height on the y-axis. Draw a smooth line of best fit between the points (you might not hit each of the points exactly). Professor Si Smology has already made a start on this, so carry on from where he left it.

Last updated: 12 December 2013

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