The term for the point on the Earth's surface directly above the earthquake's focus is called the:

The term for the point on the Earth's surface directly above the earthquake's focus is called the:

• A. Focus
• B. Hypocenter
• C. Center
• D. Epicentre

Answer: (D)

Think about how we locate an earthquake. The energy starts at the focus, which is the point inside the Earth where the rock actually ruptures (also called the hypocenter). The point on the Earth’s surface directly above that underground point is the epicentre. In other words, the epicentre is the surface projection of the focus. The other terms describe the internal origin or aren’t used for this surface location, so epicentre is the correct label. Seismologists determine it by comparing how long different seismic waves take to reach stations and triangulating the position.

Think about how we locate an earthquake. The energy starts at the focus, which is the point inside the Earth where the rock actually ruptures (also called the hypocenter). The point on the Earth’s surface directly above that underground point is the epicentre. In other words, the epicentre is the surface projection of the focus. The other terms describe the internal origin or aren’t used for this surface location, so epicentre is the correct label. Seismologists determine it by comparing how long different seismic waves take to reach stations and triangulating the position.