In seismology, the point on Earth surface that lies directly above the focus or hypocentre of an earthquake is called what?

Introduction / Context:
Earthquakes are caused by sudden release of energy within Earth crust, and seismology uses specific terms to describe locations involved in such events. Two key terms are focus and epicentre. Understanding the difference between them is important for geography and earth science. This question asks you to name the point on the surface of Earth that is located directly above the earthquake focus.

Given Data / Assumptions:

- The focus or hypocentre is the point inside the crust where the earthquake originates.
- The question asks for the name of the surface point directly above that focus.
- Options include Focus, Incentre, Epicentre and Circumcentre.
- We assume standard definitions used in seismology and geography.

Concept / Approach:
The focus, also called hypocentre, is the actual source point within Earth where rocks first slip and seismic waves begin. The epicentre is the point on the surface located vertically above the focus. It is often the place where the earthquake effects are felt strongly and where news reports locate the event. Incentre and circumcentre are geometric terms from mathematics and do not describe earthquake locations. By recalling these definitions, we can easily select the correct option.

Step-by-Step Solution:
Step 1: Identify that the question distinguishes between an internal point and a surface point.Step 2: Recall that the focus or hypocentre is inside the crust at the depth where energy is released.Step 3: Recognise that the surface point exactly above the focus is defined as the epicentre.Step 4: Note that focus is not on the surface and that incentre and circumcentre are mathematical terms for triangle centres.Step 5: Therefore, the correct term for the surface point above the focus is epicentre.

Verification / Alternative check:
To verify, recall news reports that mention the epicentre of an earthquake being near a particular city or region. Maps often show the epicentre as a mark on the surface. Diagrams in textbooks show the focus below ground and the epicentre vertically above it. These visual memories support the definition that epicentre is the surface point directly above the focus.

Why Other Options Are Wrong:
Focus: This is the internal point where the earthquake originates, not the surface point above it.
Incentre: In mathematics, this is the centre of a circle inscribed inside a triangle and has no meaning in seismology in this context.
Circumcentre: This is the centre of a circle that passes through all vertices of a triangle and again is a geometric term, not an earthquake related term.

Common Pitfalls:
Students sometimes confuse focus and epicentre or use the terms interchangeably. Another error is being distracted by purely mathematical terms like incentre and circumcentre because they sound scientific. To prevent such confusion, remember that focus is the internal origin of seismic waves, while epicentre is the surface location that lies directly above it. Linking epicentre with the idea of an epic story on the surface may serve as a simple memory aid.

Final Answer:
The point on the surface directly above the earthquake focus is called the Epicentre.