The April 5th, 2024, 4.8 magnitude earthquake that shook New Jersey and the surrounding Northeast region has led to the discovery of a previously unknown fault line. This newly identified fault line may explain the unusual pattern of shaking experienced during the quake, where the strongest tremors were felt miles away from the epicenter in Tewksbury Township, New Jersey.
While the epicenter experienced minimal damage, areas like New York City, 40-50 miles away, reported significant shaking and minor damage. This unusual distribution of seismic activity puzzled researchers, leading to further investigation.
The study, led by Won-Young Kim of Columbia Climate School’s Lamont-Doherty Earth Observatory, revealed that the earthquake’s energy traveled downwards towards the Earth’s crust and mantle boundary, approximately 20 miles underground. Upon reaching this boundary, the energy was redirected upwards, focusing the strongest shaking under the New York City area. This phenomenon explains why areas further from the epicenter experienced more intense shaking than locations closer to the origin of the earthquake.
The newly discovered fault line, running south to north and dipping eastward at a 45-degree angle, is believed to be responsible for this unusual energy redirection. Unlike traditional vertical faults, this angled fault channeled the seismic energy northeastward, leading to the unexpected shaking pattern.
This discovery highlights the difference between earthquakes in the Northeast and those on the West Coast. While West Coast earthquakes are often caused by shifting tectonic plates, Northeast quakes originate from ancient, reactivated fault zones formed millions of years ago during the separation of North America and Europe. These areas continue to adjust, resulting in occasional seismic activity.
Researchers estimate that earthquakes of this magnitude occur in the Northeast approximately every 100 years. However, the region has the potential for significantly larger earthquakes, up to magnitude 7, every few thousand years. Such a large-scale earthquake today in New Jersey would have catastrophic consequences.
Following the April earthquake, scientists deployed a network of seismometers to monitor aftershocks and gather data to map the region’s fault lines more accurately. This information will be crucial in reassessing potential earthquake hazards and updating building codes to mitigate the impact of future seismic events in the densely populated Northeast.
This recent earthquake serves as a reminder of the importance of understanding regional seismic activity and preparing for potential earthquakes, even in areas not traditionally considered high-risk zones. The discovery of the new fault line underscores the need for continued research and preparedness to minimize the impact of future earthquakes in New Jersey and the surrounding areas.
