Answer: b. 10 times weaker than the Great Chilean.
Step-by-step explanation :
- Richter scale is a numerical scale which is used to express the magnitude of an earthquake based on the seismograph recordings of the amplitude of the highest seismic wave.
- The Richter scale is a base-10 logarithmic scale.
- A base 10 logarithmic scale implies that each order of magnitude is 10 times greater than the previous one.
- Thus, even though 8.5 and 9.5 differ by a value of 1, the fact the scale is logarithmic with base 10 this means that Great Chilean earthquake is 10 times stronger than the earthquake on Kuril islands.
- Thus, the Kuril island earthquake is 10 times weaker than the Chilean earthquake.