The strongest recorded earthquake in the world took place in Chile on May 22 1960. It had a magnitude of 9.5 on the Richter scale. The strongest quake actually recorded in Canada was magnitude 8.1 on August 22 1949 and occurred off the Queen Charlotte Islands. (The strongest quake ever in Canada, estimated to be magnitude 9.0, happened on the west coast on January 26 1700, killing hundreds of First Nations people. We know the date because the resulting tsunami devastated the Japanese coastline.)

1.
How many times more powerful was the Chilean quake than the Queen Charlotte quake? (2 marks)

2. If an earthquake only half as strong as the Queen Charlotte one were to happen today, what would its magnitude be? (3 marks)

1. To determine how many times more powerful the Chilean earthquake was than the Queen Charlotte earthquake, we can compare their magnitudes on the Richter scale. The Richter scale is logarithmic, which means that each whole number increase in magnitude represents a tenfold increase in amplitude or energy release.

The Chilean earthquake had a magnitude of 9.5, while the Queen Charlotte earthquake had a magnitude of 8.1. To find the difference in magnitude, we subtract the magnitude of the Queen Charlotte earthquake from the magnitude of the Chilean earthquake:

9.5 - 8.1 = 1.4

Therefore, the Chilean earthquake was 1.4 times more powerful than the Queen Charlotte earthquake.

2. If an earthquake is only half as strong as the Queen Charlotte earthquake, we need to find half of its magnitude. Since each whole number increase on the Richter scale represents a tenfold increase in strength, we can calculate the magnitude of an earthquake that is half as strong as the Queen Charlotte earthquake by subtracting 0.5 from its magnitude.

Magnitude of Queen Charlotte earthquake: 8.1
Magnitude of earthquake half as strong: 8.1 - 0.5 = 7.6

Therefore, if an earthquake half as strong as the Queen Charlotte earthquake were to happen today, its magnitude would be 7.6.