Understanding Earthquake Magnitude and Classification

Earthquakes are measured using scales that quantify their size. The Richter scale, developed by Charles F. Richter in 1935, measures the magnitude of an earthquake, which is related to the energy released at the earthquake's source. Different magnitude ranges on the Richter scale are associated with varying levels of impact and damage.

While the Richter scale was historically significant, especially for moderate earthquakes, larger earthquakes are now often measured using the Moment Magnitude Scale (MMS). However, the concept of magnitude classification based on effects remains similar, and the terms in the options are often linked to specific magnitude ranges.

Earthquake Classification by Magnitude

Earthquakes are commonly classified based on their magnitude, which helps describe their potential effects. Although exact terms and magnitude boundaries can vary slightly between different classification systems, a widely used categorization links magnitude ranges to descriptive terms:

Analyzing the Magnitude Range 7 - 7.3

The question asks about an earthquake with a magnitude in the range ${7.0 \text{ to } 7.3}$ on the Richter scale. Looking at the typical classification table above, this magnitude range falls squarely within the ${7.0 \text{ to } 7.9}$ category.

This category is commonly termed as a "Major" earthquake and is known to cause "serious damage over large areas". The descriptive term frequently associated with the effects of such a major earthquake is "Disastrous".

Evaluating the Options

Let's consider how each option relates to the magnitude range ${7.0 \text{ to } 7.3}$ based on the standard classifications:

• Option 1: destructive - This term is typically associated with earthquakes in the ${6.0 \text{ to } 6.9}$ (Strong) magnitude range. While a 7.0-7.3 magnitude earthquake is certainly destructive, this isn't the primary classification term for this range.
• Option 2: ruinous - This term describes the outcome (causing ruin), but it is not a standard classification term used to categorize earthquakes by magnitude in typical scales.
• Option 3: disatrous - This option, despite a likely typo (standard term is "disastrous"), corresponds to the typical classification for earthquakes in the ${7.0 \text{ to } 7.9}$ magnitude range, which includes ${7.0 \text{ to } 7.3}$. A major earthquake is often described as disastrous due to the widespread and severe damage it causes.
• Option 4: catastrophic - This term is usually reserved for the most powerful earthquakes, those with a magnitude of ${8.0}$ or higher (Great earthquakes), which cause widespread, severe destruction over vast areas.

Based on the standard classification of earthquakes by magnitude, an earthquake in the ${7.0 \text{ to } 7.3}$ range is considered a Major earthquake and is commonly described as having disastrous effects.

Conclusion on Earthquake Classification

An earthquake with a magnitude on the Richter scale in the range ${7.0 \text{ to } 7.3}$ is classified as a Major earthquake, and its effects are typically described as disastrous. Therefore, among the given options, the term that best fits this range is "disastrous" (represented by "disatrous" in option 3).

Revision Table: Earthquake Magnitude and Effects

Additional Information on Earthquake Measurement

The Richter scale uses a logarithmic scale, meaning that each whole number increase in magnitude represents a tenfold increase in the amplitude of the seismic waves and approximately 32 times more energy released. Therefore, a magnitude 7.0 earthquake releases significantly more energy than a magnitude 6.0 earthquake.

The intensity of an earthquake, measured by scales like the Modified Mercalli Intensity (MMI) scale, describes the effects of the earthquake at a specific location, based on observations of damage to structures and human perception. While magnitude is a single value for an earthquake, intensity varies depending on distance from the epicenter, local geology, and building construction. Earthquakes in the ${7.0 \text{ to } 7.3}$ magnitude range typically correspond to high intensity levels (e.g., IX or X on the MMI scale) near the epicenter, signifying destructive or disastrous effects.