Earthquake of magnitude 2.7 experienced in the New York and New Jersey region
In a surprising turn of events, a 2.7-magnitude earthquake occurred near Hillsdale, New Jersey, on Tuesday at 12:11 p.m. ET. While the quake was relatively weak, the unique characteristics of the rocks in the eastern US played a significant role in allowing seismic waves to travel farther and with less attenuation.
The eastern US is home to old, stable continental interiors with fewer active faults. This age and stability contribute to seismic energy travelling more efficiently, enabling waves to be felt over larger areas. The region's rocks, primarily metamorphic and igneous, are denser and less fractured, providing a more direct and less scattered travel path for seismic waves.
Another key factor is the presence of ancient fault zones. Though many faults are millions of years old and "healed," they can still reactivate during earthquakes, affecting wave paths and seismic intensity distribution. Geologic layering and deep basin structures, such as the upper Mississippi embayment, also influence wave speed and direction due to contrasting rock densities and elastic properties.
In contrast, western US rocks tend to be younger, more fractured, and tectonically active, resulting in greater attenuation of seismic waves. The older and more coherent rock masses in the eastern US provide seismic waves a more direct and less scattered travel path, allowing them to travel in a more potent form over longer distances.
The exact location of the earthquake's epicenter was not specified, but it was reported by dozens of people from Staten Island to southwest Connecticut. The seismic energy released by the earthquake was recorded by the US Geological Survey, although no specific information about the cause of the earthquake was provided.
The US Geological Survey did not provide any information about the frequency of earthquakes in the area, and no explicit detailed data on specific rock velocities or seismic properties were found in the search results. However, the emphasis on the age and healed nature of faults, as well as the stability and type of bedrock, is a key distinctive feature affecting seismic wave propagation in the eastern US.
As we continue to learn more about the Earth's seismic activity, understanding the unique characteristics of different regions' rocks becomes increasingly important. This event serves as a reminder that even seemingly small earthquakes can have significant impacts due to the properties of the rocks they occur within.
CNN's Eric Zerkel contributed to this report.
The peculiar characteristics of the rocks in the eastern US, being older, stable, and less fractured, contribute to seismic energy traveling more efficiently, making seismic waves feel over larger areas. Contrastingly, the western US rocks tend to be younger, more fractured, and tectonically active, resulting in greater attenuation of seismic waves, allowing seismic waves in the eastern US to travel in a more potent form over longer distances.
