Chapter 9, Problem 22PT

To determine

To calculate: To find how many times as great was the Santa Maria eruption rate that the Mount St. Helen eruption rate

Answer to Problem 22PT

Santa Maria eruption rate is twice the Mount St. Helen eruption rate

Explanation of Solution

Given information: Table showing the greatest amounts of lava in cubic meters per second that erupted from six volcanoes:

Volcano	Date	Eruption rate
Mount St. Helens	1980	$2\times {10}^4$
Naguruhoe	1975	$2\times {10}^3$
Helka	1970	$4\times {10}^3$
Agung	1963	$3\times {10}^4$
Bezymianny	1956	$2\times {10}^5$
Hekla	1947	$2\times {10}^4$
Santa Maria	1902	$4\times {10}^4$

Calculation:

From the table,

Eruption rate of Santa Maria $=4\times {10}^4$

Eruption rate of Mount St. Helens $=2\times {10}^4$

Expression to find how many times as great was the Santa Maria eruption rate that the Mount St. Helen eruption rate is

  $\frac{4\times {10}^4}{2\times {10}^4}$

On solving the above expression:

  $\begin{array}{l}\Rightarrow \frac{4\times 1}{2\times 1}\\ \Rightarrow \frac{2\times 1}{1\times 1}\\ \Rightarrow 2\end{array}$

Conclusion:

Hence, Santa Maria eruption rate is twice the Mount St. Helen eruption rate