In earthquake terminology, what is the name given to the place of origin inside the earth where an earthquake actually starts?

Introduction / Context:
Earthquake related terms are an important part of physical geography and general science. This question asks about the specific name given to the place inside the earth where an earthquake begins. Understanding the difference between that internal point and the point directly above it on the surface is crucial for scoring full marks on geography based MCQs.

Given Data / Assumptions:

• The subject is the origin of an earthquake.
• The location is inside the earth where seismic waves first start.
• Options include epicentre, seismal, focus, and amphidromic point.
• We must identify the correct technical term for this internal origin point.

Concept / Approach:
In earthquake terminology, the point inside the earth where the rocks first rupture and seismic waves originate is called the focus or hypocentre. The point on the earth surface directly above the focus is known as the epicentre. The approach is to recall this pair of terms and choose focus when the question clearly mentions the place of origin inside the earth, not on the surface. The other terms given either do not apply or are unrelated to earthquakes.

Step-by-Step Solution:
Step 1: Identify whether the question is asking about a point inside the earth or on the surface. It clearly states inside the earth. Step 2: Recall that the internal point where the earthquake starts is called the focus. Step 3: Remember that the point on the surface vertically above the focus is called the epicentre, which is different. Step 4: Check the options and locate focus among them. Step 5: Select focus as the correct answer, since it fits the definition given.

Verification / Alternative check:
You can verify this by recalling standard diagrams in geography textbooks that show the focus at some depth below the surface and the epicentre directly above it. Labels on such diagrams always mark the internal origin as focus or hypocentre. Additional terms like seismic waves and seismograph are related to earthquake measurement but do not change the basic pair focus and epicentre. This visual memory supports the choice of focus for the origin point inside the earth.

Why Other Options Are Wrong:

• Epicentre: This is the point on the earth surface directly above the focus, not the internal origin.
• Seismal: This is not a standard term for the origin point; related words are seismic or seismology.
• Amphidromic Point: This term is used in oceanography for points with zero tidal range, not for earthquakes.

Common Pitfalls:
The most common mistake is confusing focus with epicentre because both are mentioned together in earthquake explanations. Students sometimes pick epicentre because it sounds more familiar or because they do not pay attention to whether the question refers to the interior or the surface. To avoid this, always underline or mentally highlight phrases like inside the earth or at the surface when you read the question. This will guide you to choose focus when the internal origin is meant.

Final Answer:
The place of origin inside the earth where an earthquake starts is called the Focus.