A technician installs strong motion and high frequency sensors April 11 at a station selected to record aftershock data from the April 5, 2024 Whitehouse Station, N.J. earthquake.
Why do earthquakes occur in the middle of the continent far from plate boundaries?
Most earthquakes occur near tectonic plate boundaries, where the Earth's crust is composed of large fragments that interact with one another. These interactions can involve plates sliding past each other, colliding, or moving apart. However, a map of the U.S. shows that earthquakes also take place in the interior regions of the continent, though less frequently than those along the edges. This raises the question: why do earthquakes occur away from tectonic plate boundaries? Research into this phenomenon is limited, but studies indicate that ancient regional and local variations in the Earth's crust play a significant role. These variations reflect stress conditions that have persisted for millions of years, often stemming from long-ago tectonic activities such as mountain-building and continental rifting. Stress is continuously transmitted from the boundaries throughout the tectonic plates. When this stress encounters a pre-existing weakness in the crust—such as fractures or faults from older geological events—the likelihood of an earthquake occurring in that location increases.
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Related Content
What is an earthquake and what causes them to happen?
An earthquake is caused by a sudden slip on a fault. The tectonic plates are always slowly moving, but they get stuck at their edges due to friction. When the stress on the edge overcomes the friction, there is an earthquake that releases energy in waves that travel through the earth's crust and cause the shaking that we feel. In California there are two plates - the Pacific Plate and the North...
Why should people in the eastern United States be concerned about earthquakes?
1) Severe earthquakes have occurred in the eastern U.S.: In November of 1755, an earthquake with an estimated magnitude of 6.0 and a maximum intensity of VIII occurred about 50 miles northeast of Boston, Massachusetts. Boston was heavily damaged. Other strong earthquakes recorded in the continental US were centered in southeastern Missouri near the border with Arkansas, Kentucky and Tennessee. In...
Where are the faults in the Central and Eastern U.S.?
Faults vs. Fault Lines on a Map In order to answer this question, we first need to explain some basics about faults. Faults are different from fault lines. A fault is a three-dimensional surface within the planet that might extend up to the surface or might be completely buried. In contrast, a fault line is where the fault cuts the Earth's surface… if indeed it does. The most prominent faults in...
What is a fault and what are the different types?
A fault is a fracture or zone of fractures between two blocks of rock. Faults allow the blocks to move relative to each other. This movement may occur rapidly, in the form of an earthquake - or may occur slowly, in the form of creep. Faults may range in length from a few millimeters to thousands of kilometers. Most faults produce repeated displacements over geologic time. During an earthquake, the...
Where can I find a fault map of the United States? Is one available in GIS format?
An online map of United States Quaternary faults (faults active in the last 1.6 million years which places them within the Quaternary Period) is available via the Quaternary Fault and Fold Database . There is an interactive map application to view the faults online and a separate database search function. KML (Google Earth-type) files and GIS shape files are also available for download from the...
USGS deploys “aftershock kits” to study Whitehouse Station earthquakes
A technician installs strong motion and high frequency sensors April 11 at a station selected to record aftershock data from the April 5, 2024 Whitehouse Station, N.J. earthquake.
National Preparedness Month Spotlight on Earthquakes [Part 1]
Earthquakes can affect millions of people across the United States. But do you know what causes them? This video will tell you.
September is National Preparedness Month. Learn more about the natural hazards you may face in our feature story.
Earthquakes can affect millions of people across the United States. But do you know what causes them? This video will tell you.
September is National Preparedness Month. Learn more about the natural hazards you may face in our feature story.
New Madrid Seismic Zone
The New Madrid seismic zone in Central U.S.
A seismic zone is an area of seismicity probably sharing a common cause.
The New Madrid seismic zone in Central U.S.
A seismic zone is an area of seismicity probably sharing a common cause.
Fault Types
Strike-slip, normal, and reverse faults. A reverse fault with a small dip angle is called a thrust fault.
Strike-slip, normal, and reverse faults. A reverse fault with a small dip angle is called a thrust fault.
Faults
When landmasses collide, rock layers can break. Geologists call these breaks "faults." Rock layers are offset in this image in western China, making the faults remarkably clear. The different colors indicate rocks that formed at different times and in different environments.
When landmasses collide, rock layers can break. Geologists call these breaks "faults." Rock layers are offset in this image in western China, making the faults remarkably clear. The different colors indicate rocks that formed at different times and in different environments.
Low-Flying Airplane Maps New Madrid Zone
Starting around July 10, 2013, an airplane operating under contract to the USGS will be making low-level flights over a 1400-square-mile area in the New Madrid Seismic Zone. This airplane is a Cessna-180, specially modified for low-altitude geophysical surveys.
Starting around July 10, 2013, an airplane operating under contract to the USGS will be making low-level flights over a 1400-square-mile area in the New Madrid Seismic Zone. This airplane is a Cessna-180, specially modified for low-altitude geophysical surveys.
Tish Tuttle: Prehistoric New Madrid Earthquakes
Description available soon
Related Content
What is an earthquake and what causes them to happen?
An earthquake is caused by a sudden slip on a fault. The tectonic plates are always slowly moving, but they get stuck at their edges due to friction. When the stress on the edge overcomes the friction, there is an earthquake that releases energy in waves that travel through the earth's crust and cause the shaking that we feel. In California there are two plates - the Pacific Plate and the North...
Why should people in the eastern United States be concerned about earthquakes?
1) Severe earthquakes have occurred in the eastern U.S.: In November of 1755, an earthquake with an estimated magnitude of 6.0 and a maximum intensity of VIII occurred about 50 miles northeast of Boston, Massachusetts. Boston was heavily damaged. Other strong earthquakes recorded in the continental US were centered in southeastern Missouri near the border with Arkansas, Kentucky and Tennessee. In...
Where are the faults in the Central and Eastern U.S.?
Faults vs. Fault Lines on a Map In order to answer this question, we first need to explain some basics about faults. Faults are different from fault lines. A fault is a three-dimensional surface within the planet that might extend up to the surface or might be completely buried. In contrast, a fault line is where the fault cuts the Earth's surface… if indeed it does. The most prominent faults in...
What is a fault and what are the different types?
A fault is a fracture or zone of fractures between two blocks of rock. Faults allow the blocks to move relative to each other. This movement may occur rapidly, in the form of an earthquake - or may occur slowly, in the form of creep. Faults may range in length from a few millimeters to thousands of kilometers. Most faults produce repeated displacements over geologic time. During an earthquake, the...
Where can I find a fault map of the United States? Is one available in GIS format?
An online map of United States Quaternary faults (faults active in the last 1.6 million years which places them within the Quaternary Period) is available via the Quaternary Fault and Fold Database . There is an interactive map application to view the faults online and a separate database search function. KML (Google Earth-type) files and GIS shape files are also available for download from the...
USGS deploys “aftershock kits” to study Whitehouse Station earthquakes
A technician installs strong motion and high frequency sensors April 11 at a station selected to record aftershock data from the April 5, 2024 Whitehouse Station, N.J. earthquake.
A technician installs strong motion and high frequency sensors April 11 at a station selected to record aftershock data from the April 5, 2024 Whitehouse Station, N.J. earthquake.
National Preparedness Month Spotlight on Earthquakes [Part 1]
Earthquakes can affect millions of people across the United States. But do you know what causes them? This video will tell you.
September is National Preparedness Month. Learn more about the natural hazards you may face in our feature story.
Earthquakes can affect millions of people across the United States. But do you know what causes them? This video will tell you.
September is National Preparedness Month. Learn more about the natural hazards you may face in our feature story.
New Madrid Seismic Zone
The New Madrid seismic zone in Central U.S.
A seismic zone is an area of seismicity probably sharing a common cause.
The New Madrid seismic zone in Central U.S.
A seismic zone is an area of seismicity probably sharing a common cause.
Fault Types
Strike-slip, normal, and reverse faults. A reverse fault with a small dip angle is called a thrust fault.
Strike-slip, normal, and reverse faults. A reverse fault with a small dip angle is called a thrust fault.
Faults
When landmasses collide, rock layers can break. Geologists call these breaks "faults." Rock layers are offset in this image in western China, making the faults remarkably clear. The different colors indicate rocks that formed at different times and in different environments.
When landmasses collide, rock layers can break. Geologists call these breaks "faults." Rock layers are offset in this image in western China, making the faults remarkably clear. The different colors indicate rocks that formed at different times and in different environments.
Low-Flying Airplane Maps New Madrid Zone
Starting around July 10, 2013, an airplane operating under contract to the USGS will be making low-level flights over a 1400-square-mile area in the New Madrid Seismic Zone. This airplane is a Cessna-180, specially modified for low-altitude geophysical surveys.
Starting around July 10, 2013, an airplane operating under contract to the USGS will be making low-level flights over a 1400-square-mile area in the New Madrid Seismic Zone. This airplane is a Cessna-180, specially modified for low-altitude geophysical surveys.
Tish Tuttle: Prehistoric New Madrid Earthquakes
Description available soon