Focus vs Epicenter
Focus and epicenter are words that are commonly heard in geology when earthquakes and their causes are being taught. With similarities in between, these two terms cause a lot of confusion for the students. These words are frequently used while reporting incidents of earthquakes in media. This article attempts to highlight the differences between focus and epicenter for the readers.
Focus
Focus is the point below the surface of the earth where an earthquake originates. This is the point where rocks first rupture or break when an earthquake takes place due to movement of bedrock and release of energy in a violent form. This point is also called hypocenter, and this is from where seismic waves travel to all other directions. The waves are extremely forceful at the start but slowly die down. These waves can make earth vibrate like a tuning fork.
Epicenter
As focus cannot be seen by people, the concept of epicenter was introduced to let people visualize the focus from where the earthquake originated. This epicenter is a point directly above the focus and is situated on the surface of the earth. Thus for practical purposes, epicenter is taken to be the center or the origin of earthquake though the point below the surface of the earth remains the spot where it originated.
What is the difference between Focus and Epicenter?
• Focus is the actual point below the surface of the earth where an earthquake originates whereas epicenter is a point directly above it, and it lies on the surface of the earth.
• It is the focus that is the origin of the earthquake and seismic waves travel in all direction like ripples in a pond when a stone is thrown inside.
• Epicenter is also called hypocenter.
• Area around epicenter is the one that is hit the hardest by an earthquake and can be seen by the people.
• When the focus is shallow, the magnitude of the earthquake registered at the epicenter is higher than when the focus is deep.
• The cause of the earthquake is determined by studying focus whereas epicenter gives information about the extent of damage.