Earthquakes are classified based on their depth of origin: shallow earthquakes occur within the top 70 kilometers of the Earth's surface, intermediate earthquakes occur between 70 and 300 kilometers deep, and deep earthquakes occur beyond 300 kilometers below the surface. These depths help seismologists understand the seismic activity and associated geological processes occurring in different zones within the Earth.
A shallow earthquake occurs at a shorter depth from the surface of land, which can result in a louder, stronger quake. As an example, in 2011-2012, Ohio had a series of shallow quakes less than 2 miles beneath the surface, related to shale drilling. An intermediate earthquake occurs at a deeper depth than a shallow quake and likely involves natural fault lines.
Shallow earthquakes are typically found in the upper 70 kilometers of the Earth's crust, particularly along tectonic plate boundaries. These earthquakes are responsible for the most damage and are often associated with regions of high seismic activity, such as the Pacific Ring of Fire.
Deep focus earthquakes are seismic events that occur at depths greater than 300 kilometers (approximately 186 miles) within the Earth's crust or upper mantle. They are typically associated with subduction zones, where one tectonic plate is forced beneath another. These earthquakes can release significant amounts of energy and are less common than shallow earthquakes, which occur at shallower depths. Due to their depth, deep focus earthquakes often produce less surface shaking compared to shallow ones, but they can still be felt over large distances.
At divergent and transform boundaries.
The classification scale used to describe the depth of origin of earthquakes is based on three categories: shallow (0-70 km), intermediate (70-300 km), and deep (>300 km) earthquakes. The depth of an earthquake's origin can help determine its potential impact and the type of seismic waves produced.
Earthquakes that occur at depths less than 70 km are classified as shallow-focus earthquakes, while those between 70-300 km are called intermediate-focus earthquakes. Deep-focus earthquakes occur at depths greater than 300 km. The location and distribution of earthquakes are governed by the movement of tectonic plates along fault lines, with seismic activity concentrated at plate boundaries such as subduction zones and transform boundaries.
An intermediate earthquake is a seismic event that falls between shallow and deep earthquakes in terms of depth. These earthquakes typically occur at depths ranging from 70 to 300 kilometers beneath the Earth's surface. Intermediate earthquakes can cause significant damage due to their proximity to the Earth's crust.
Earthquakes are classified based on their depth of origin: shallow earthquakes occur within the top 70 kilometers of the Earth's surface, intermediate earthquakes occur between 70 and 300 kilometers deep, and deep earthquakes occur beyond 300 kilometers below the surface. These depths help seismologists understand the seismic activity and associated geological processes occurring in different zones within the Earth.
A shallow earthquake occurs at a shorter depth from the surface of land, which can result in a louder, stronger quake. As an example, in 2011-2012, Ohio had a series of shallow quakes less than 2 miles beneath the surface, related to shale drilling. An intermediate earthquake occurs at a deeper depth than a shallow quake and likely involves natural fault lines.
Shallow earthquakes are typically found in the upper 70 kilometers of the Earth's crust, particularly along tectonic plate boundaries. These earthquakes are responsible for the most damage and are often associated with regions of high seismic activity, such as the Pacific Ring of Fire.
Earthquakes occurring at a depth of less than 70 km are classified as 'shallow-focus' earthquakes, while those with a focal-depth between 70 and 300 km are commonly termed 'mid-focus' or 'intermediate-depth' earthquake.
Shallow
Shallow earthquakes occur within the top 70 kilometers of the Earth's crust, known as the seismogenic zone. These earthquakes are typically associated with transform plate boundaries, divergent plate boundaries, and some convergent plate boundaries, where tectonic plates interact and generate seismic activity.
Earthquakes with shallow foci are usually more damaging because their seismic energy doesn't have to travel far to reach the Earth's surface, leading to stronger ground shaking. This can result in more destruction of buildings, infrastructure, and landscapes in populated areas near the epicenter. Additionally, shallow earthquakes have a more direct impact on the surface, making them more destructive compared to deeper earthquakes.
All of New Zealand has earthquakes. Have a look for a map of NZ earthquakes 1990 - 99 on the gns.cri.nz website. Shallow earthquakes are spread indifferently throughout NZ. And these are the ones of most importance to buildings etc. Deep earthquakes have a different distribution, and are more closely associated with the descending Pacific Plate. The shallow earthquakes reflect the strains generated by the plate movement and the subsequent redistribution of strains.
Earthquakes with shallow focus, typically located less than 70 km below the Earth's surface, are more likely to cause significant damage because the seismic energy does not have to travel far to reach the surface, resulting in stronger shaking. Additionally, shallow earthquakes occur in the Earth's brittle crust where most people and infrastructure are located, increasing the potential for damage.