Does Earthquake Activity Occur More Frequently At Ocean Trenches or Ocean Ridges?

The tsunami that struck Thailand in 2004 was caused by an earthquake beneath a nearby oceanic trench.
••• Paula Bronstein/Getty Images News/Getty Images

Earthquakes do not occur everywhere throughout the world. Instead, the great majority of quakes take place in or near narrow belts that coincide with the boundaries of the tectonic plates. These plates make up the rocky crust at the Earth's surface and underlie both the continents and the oceans. Oceanic crust is sometimes compared to a conveyor belt: New crust is continually created at midocean ridges and destroyed where it disappears into trenches at the edges, usually where the ocean collides with a continent. Both oceanic ridges and trenches are sites of earthquake activity.

Earthquake Basics

An earthquake consists of the shock waves created when rocks below the surface suddenly slip along a fault plane. Earthquake are classified by their intensity, which is the amount of energy released by the movement and by the depth to the center of the slip zone, or focus.

Ridges Vs. Trenches

Although earthquakes occur along all plate boundaries, they are much more common along collision zones that include an oceanic trench than they are at midocean ridges. This difference in frequency is because at midoceanic ridges, the crust is both thin and hot, which reduces the amount of pressure (called strain) that can build up before slip on a fault happens. The rock at oceanic ridges is also somewhat softer because it is hot. At trenches, the crust is thicker and cooler, which allows more strain to accumulate, leading to more earthquakes.

Related Articles

How Does a GPS Transmitter Work on Studying Plate Movements?
How Does Pressure Affect Plate Tectonics?
How Does Plate Tectonics Affect the Rock Cycle?
The Difference Between an Earthquake & a Volcano
What Happens Underground During an Earthquake?
How Does a Volcano Erupt?
Three Types of Convergent Boundaries
What Is the Primary Force That Causes the Seafloor...
What Are the Features of a Subduction Zone?
Three Types of Stress on the Earth's Crust
The Definition of Tectonic Activity
What Kind of Eruption Would You Expect at a Rift?
Landforms Caused by Plate Tectonics
What Type of Plate Boundary Is the Aleutian Trench?
How Do Earthquake Activities Influence the Formation...
10 Facts About Plate Tectonics
What Are Convergent, Divergent & Transform Boundaries?
Ancient Fault Lines in Pennsylvania
How Does a GPS Transmitter Work on Studying Plate Movements?
Differences Between Extrusive and Intrusive Rocks

Dont Go!

We Have More Great Sciencing Articles!