Risk of Tectonic Hazards (Edexcel A Level Geography)

Study Figure 1 below. This data in Figure 1 was collected to investigate whether there was a significant relationship between the percentage of silica and the percentage of volatile gases in lava samples, found at 12 contrasting volcanic locations.

Volatile gases – gases emitted by volcanoes at high temperature such as water vapour, carbon dioxide and sulphur dioxide.

i)

Complete Figure 1 by calculating ∑d² .

(1)

ii)

The formula for Spearman’s rank correlation coefficient value r_s is given below; in this data set n is equal to 12.

r_s = 1 −

Calculate the value of r_s to two decimal places for the data given. You must show your working.

(2)

iii)

The tables below show the two hypotheses that are being tested and the critical values of Spearman’s rank rs value when n = 12.

Using the Spearman’s rank correlation rs value calculated in (a)(ii), state which hypothesis can be accepted.

(1)

Study Figure 1a in the Resource Booklet and Figure 1b below.

Figure 1a

Tectonic setting of New Zealand

This data in Figure 1b was collected to investigate whether there was a significant difference in earthquake depth at the two plate boundaries shown in Figure 1a.

Figure 1b

Frequency and focal depth of earthquakes in New Zealand, 2016

i)

Calculate the average monthly frequency of earthquakes at the two plate boundaries.

You must show your working.

(2)

ii)

A Student’s t-test was used to determine whether there was a statistical difference in the mean focal depth of the earthquakes at the two plate boundaries.

Two hypotheses were tested:

Using the partially completed Student’s t-test below, calculate the value of t.

t =.....................................

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iii)

Study Figure 1c below.

Figure 1c

Critical values for this Student’s t-test

Using the Student’s t-test value calculated in (a) (ii), state whether there is a significant difference between the mean focal depth of the earthquakes.

(1)

Study Figure 1 in the Resource Booklet.

Figure 1

A graph showing the areal extent of selected volcanic hazards

For each volcanic hazard shown in Figure 1, draw a line from the site of eruption along the dotted line to show the areal extent of the hazard.  An example is shown for Hazard X.

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