The strength of an earthquake is rated on a scale called Richter scale.

Explanation

### Step-by-Step Text Solution:

1. **Understanding the Question**: The question asks about the scale used to rate the strength of an earthquake.

2. **Identifying the Scale**: The scale used for measuring the strength of an earthquake is called the Richter scale.

3. **Function of the Richter Scale**: The Richter scale calculates the magnitude of an earthquake, which represents its size or strength.

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