Exercise: 

Could Eldfell Volcano Erupt Soon?

High School Appropriate

Section 1.

    On March 9, 2000 and October 7, 2001, a group of Central Kings students climbed the famous Eldfell volcano. On their ascent, they gathered thermal data at different locations on the volcano. 

    It is not easy to determine the depth of the magma beneath a volcano because “so many factors impact heat flow including the temperature of the magma, size of the magma body, rate of ascent, and the thermal characteristics of the overlying rock. Most of the time we use seismicity to determine the depth to a magma chamber.”

Video Clip: Thermal Readings Location G. Allow 2 minutes to load. (Dial-up internet connection will take 15 minutes to load)

Questions

  1. Using the table below, calculate the average temperature measurements taken by the students in C^o and F^o.  Table 1. 

Table 1.

Thermal Measurements on the Eldfell Volcano, October 7, 2001 and March 9, 2000.

  Date: October 7^th, 2001                                           Date : March 9^th, 2000

Location                      Celsius               Fahrenheit                  Celsius            Fahrenheit

 NA= Not Available

2. As one descends into the earth’s crust, the temperature increases 1 degree Celsius for every 40 meters. In active volcano areas, it can be 10 times greater. Using this theory, for every 40 meters of descent, the temperature increases 10^C.  Estimate the depth on the magma, assuming that most minerals melt at 1000^C. Please show all your math work.

3. Using the air photo of Eldfell, Is there any pattern to the temperature and the location or elevation?

Eldfell Volcano

Location/Elevation

A 75m

B 140m

C 150m

D 155m

E 200m

F 203m

G 204m

Section 2.

  1.  Answer the following questions based on an eyewitness account and the diagram of Heimaey. (Diagram 1.)

  “Great clouds of debris, hot lava, and black ash have been set free and now covers much of the Island of Heimaey. The eruption created a rift nearly two kilometers long across the eastern edge of the island, throwing up a torrent of boiling lava.  Tonight the eruption is growing in intensity and the rift is still developing, northwards now, beneath the sea." The refugees, many of whom were ferried to the mainland by air, say they have given up all hope; they fear they may never be able to return to their homes.  Tonight Eldfell is angrier than ever and geologist are aware that it could be weeks, even months, before they can judge if the island can ever be reinhabited...”

(three months later)  “... For the people of this island, this eruption was totally unexpected.  Though only a tenth of the town was destroyed by lava, the remaining buildings are now collapsing under the weight of the volcanic ash that constantly falls.  The eruption has continued for more than three months and it could be more than three years before it ends, no one knows ...”

(a) What were the main products of this eruption?

(b) Which of these products was the most extensive?

(c) What is the surface area of the lava flow formed by the Eldfell eruption (in sq. kilometers.)?

(d) This eruption was partly from a long fissure in the crust.  How did this affect the distribution or direction of the lava flow?

  2.  Using the map scale and the average thickness of the ash at 1m, estimate the total volume of ash thrown out by the volcano 

Use: (3.14 x (r²) x 30 cm = m³).

  3. What was the chief hazard to the town on the island?

4. At the time of the eruption the wind was blowing in one direction.  What was this direction?  Remember:  Wind readings are given from origin.

5. What would have been the least hazardous direction for the wind to have been blowing from at the time?  Why? Remember:  Wind readings are given from origin.

6. After the eruption the town was actually reinhabited and once again became a major fishing port.  The eruption actually benefited the town in this regard.  Consult the map and indicate how the eruption has helped the harbor.

7.Using the information from section 2, question 1 c., how much volume of lava was expelled by the Eldfell volcano if the average thickness is 10 meters. Please give answer in cubic meters. (use the average length and width measurements from section 2, 1c.)

 Use L X W X H = Volume

8. What were the two (2) main concerns of the advancing lava flow?

9.    BONUS QUESTION

  Assuming your answer is correct for question 7, consider the following.

You and two other students were late for class, so the teacher has assigned the late trio   to replicate and build the lava flow of the Eldfell eruption out of styrofoam meter blocks, each measuring a single cubic meter. The structure would be located in a very large open area by the school. Each student will be required to work eight hours a day ( 9 am to 5 p.m. ), 5 days a week with no summer break.  It takes an average of one minute to move one styrofoam block from the truck, which is dropping off the blocks, to the site where the structure will be located.

Question:  How long will it take the three students to replicate the amount of lava expelled by the Eldfell volcano with styrofoam blocks?

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Last changed: September 02, 2002